Article: 226114 of rec.radio.amateur.antenna Subject: Re: horiz. loop - triangle shape work? From: Ed G References: <1152245793.947530.36900@m79g2000cwm.googlegroups.com> <12aroqj2chrpu45@corp.supernews.com> Message-ID: Date: 07 Jul 2006 05:14:35 GMT dplatt@radagast.org (Dave Platt) wrote in news:12aroqj2chrpu45 @corp.supernews.com: > >>Triangle will work fine. >> >>160m probably not; it's a bit short. It would help if you included a >>relay opposite the feedpoint to open it on 160m. > > I've read of people using an L/C resonant trap instead of a relay, for > just this purpose. The trap opens the loop on the lowest band, and > appears as a capacitive reactance in series with the loop on the > higher-frequency bands. > > That's interesting, Dave. Thanks. Will look into that as a relay would be tricky given the location and height of my proposed loop. Ed Article: 226115 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: horiz. loop - triangle shape work? Date: 6 Jul 2006 22:44:07 -0700 Message-ID: <1152251047.124924.40880@m73g2000cwd.googlegroups.com> References: Trap seems like a fine idea... If it were not a multiband loop, I think you could use a relay with the coil in parallel with the contacts, so you could run DC on the feedline (if it were a dual bander of some sort) but the high voltages present on the open wire feeder would make it awfully hard to choke off the RF for whatever DC injection scheme you were using. I think you'd basically need a tuner with DC continuity, and the CLC tee that is so common in tuners isn't one. I guess you need a big enough C on the higher bands to look like a short circuit in that trap if you want to have the loop appear to be a closed loop, but maybe that's not very important. 73, Dan Article: 226116 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1152245793.947530.36900@m79g2000cwm.googlegroups.com> <12aroqj2chrpu45@corp.supernews.com> <1152251047.124924.40880@m73g2000cwd.googlegroups.com> Subject: Re: horiz. loop - triangle shape work? Date: Fri, 7 Jul 2006 07:36:59 +0100 Message-ID: A relay inserted in an antenna wire can be operated via a pair of wires (20 gauge twin speaker cable) which, in parallel, form the single antenna wire. At the shack end, DC power is fed into the pair of wires via an RF choke. The choke consists of a pair of wires (more 20 gauge twin speaker cable) wound on a ferrite rod. Been there. Done that! I used a single-contact reed relay. ---- Reg. Article: 226117 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: HFTA-ARRL-Space Date: Thu, 06 Jul 2006 23:56:02 -0700 Message-ID: References: <52ec8$44a69065$453d9423$8142@FUSE.NET> <44A6F80E.6010102@fuse.net> <59kea2tv6pma7sic35eufbijongfaa6cl3@4ax.com> <44ADCA31.2010307@fuse.net> On Thu, 06 Jul 2006 22:42:57 -0400, jawod wrote: >PseudoBrewster's Angle (PBA) is the "angle at which the reflected wave >is 90 degrees out of phase with respect to the direct wave" (p. 3-13 >ARRL Antenna Book). Hi John, That sounds like piss-poor definition. >I see now that Both Brewster and PBA have to do with polarization. And certainly one has very little to do with the other - except for polarization. I'm surprised the author of that article didn't append his own name to the angle. >Not really looking for a QSO. Just trying to imagine SWL from a >different vantage point, I guess. Somewhere near the 15 meter band you can get the noise field from Jupiter. Not exactly sentient, but still an exotic contact. 73's Richard Clark, KB7QHC Article: 226118 of rec.radio.amateur.antenna From: "hamguy1" Subject: looking for 2 metre mobile radio Date: Fri, 7 Jul 2006 17:06:41 +1000 Message-ID: <44ae07f7$1$21440$afc38c87@news.optusnet.com.au> hi there newgroups, i live in australia im looking for either a yaesu kenwood icom or similar 2 metre for my mobile with dtmf mic preferably if anyone in the usa etc has 1 i would pay shipping to australia .thanks in advance david nsw australia . Article: 226119 of rec.radio.amateur.antenna From: "oli" Subject: Antennas in the World, submit your web pages. Date: Fri, 7 Jul 2006 10:27:54 +0200 Message-ID: <44ae1b10$0$1019$ba4acef3@news.orange.fr> This is a free database where you could find some links about antennas. From customers or simple person who use or build antennas on different frequencies. http://www.antenna-street.com/antennas/ Good visite Oli Article: 226120 of rec.radio.amateur.antenna From: KC1DI Subject: Re: horiz. loop - triangle shape work? Date: Fri, 07 Jul 2006 06:37:46 -0400 Message-ID: <44AE397A.9070808@gmail.net> References: Ed G wrote: > Anyone have experience with horizontal loops in a triangle shape? > > I have trees on my property that will allow this configuration. I'll > have about 100' on each of the three sides. It is pretty much an > equilaterl triangle, and the height should be about 60 feet. I'd like > opinions before I go to the effort of getting it up. I'd also like > opinions on whether or not it should tune at all on 160M. I have an MFJ > balanced tuner to feed the 600 ohm ladder line I plan on using. > > Ed K7AAT > Hi Ed, Your Loop is about the same as I'm using here it works great on 80-10m But 160 is a bit of a stretch for it.. and I use an inv. L on that band when I'm active there. But it's been a great loop here on the other bands. You might try it first before adding relays and traps .. how well it tunes will depend upon the range the tuner will handle. It should give a good high angle lob on 160 and be good for local out to say 500 or 1000 miles. 73 Dave KC1DI Article: 226121 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: horiz. loop - triangle shape work? References: <1152245793.947530.36900@m79g2000cwm.googlegroups.com> <12aroqj2chrpu45@corp.supernews.com> <1152251047.124924.40880@m73g2000cwd.googlegroups.com> Message-ID: <9wsrg.205$2v.125@newssvr25.news.prodigy.net> Date: Fri, 07 Jul 2006 12:33:09 GMT Reg Edwards wrote: > A relay inserted in an antenna wire ... > Been there. Done that! I used a single-contact reed relay. No arcing problems? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226122 of rec.radio.amateur.antenna From: Dan Andersson Subject: Re: I really ned help here. Date: Fri, 07 Jul 2006 13:41:58 +0100 References: Message-ID: VE2CJW wrote: > Ok you antenna gurus, I have a funny problem. Whenever I try to reach a > certain repeater on 2 meters, (146.700-), I can't do it. The repeater is > about 25 miles from here. I have an outside antenna with 6 db of gain > similar to a Diamond, a new coax and 50 watts of power. The base of the > antenna is about 15 feet fron the ground and the repeater doesn't need a > tone. What's funny is that I can reach repeaters that are a lot farther > than this one but not on the the same bearing. A friend of mine who lives > about 3 miles from here has no problem whatsoever in reaching the same > repeater. Some hams who live farther from the repeater than me can use it > with no problem. The only difference I can spot is that there are a few > houses around mine that are 4 stories high while mine is a bungalow. Could > this be the reason or am I missing something here? Thanks for any help. > > VE2CJW, Mike. TX Power doesn't solve everything... If you can hear the repeater and it's in the same range of tx power that you use, you can reach it. Your problem is probably an error in the subtone setting... Have you checked if the repeater use a subtone? If the tone settings and frequency shift etc, are correct. Take your rig to your mate and connect it to his antenna. Cheers Dan / M0DFI Article: 226123 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1152245793.947530.36900@m79g2000cwm.googlegroups.com> <12aroqj2chrpu45@corp.supernews.com> <1152251047.124924.40880@m73g2000cwd.googlegroups.com> <9wsrg.205$2v.125@newssvr25.news.prodigy.net> Subject: Re: horiz. loop - triangle shape work? Date: Fri, 7 Jul 2006 14:38:02 +0100 Message-ID: <_pCdnSTtaaZR9DPZRVnyjQ@bt.com> > Reg Edwards wrote: > > A relay inserted in an antenna wire ... > > Been there. Done that! I used a single-contact reed relay. > > No arcing problems? > -- > 73, Cecil ================================== No arcing problem that I ever detected. Transmitter was 100 watts. I think the relay was rated at 750 volts and it may have been a vacuum type. Only used on the 160 and 80m bands. It eventually failed because of intermittent contact on receive when no wetting current flowed. Perhaps it should have been mercury wetted. ---- Reg. Article: 226124 of rec.radio.amateur.antenna From: Tron Subject: Re: Horizontal HF Loop Date: Fri, 07 Jul 2006 14:29:36 -0000 Message-ID: <12asrugmriuk627@corp.supernews.com> References: Newman wrote: > > Anyone here tried an HF horizonal loop built around residence? (either > attached under eaves or to trees very close by)... > Did it work? Affects of antenna on residence electronics and vice versa? > (100 watt TX) > Would plan to use on several bands w/antenna tuner & open wire feed. > Tnx for comments... http://www.google.com/search?q=directional+discontinuity+ring+radiator Article: 226125 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: horiz. loop - triangle shape work? References: <1152245793.947530.36900@m79g2000cwm.googlegroups.com> <12aroqj2chrpu45@corp.supernews.com> <1152251047.124924.40880@m73g2000cwd.googlegroups.com> <9wsrg.205$2v.125@newssvr25.news.prodigy.net> <_pCdnSTtaaZR9DPZRVnyjQ@bt.com> Message-ID: Date: Fri, 07 Jul 2006 14:41:54 GMT Reg Edwards wrote: > No arcing problem that I ever detected. Transmitter was 100 watts. I > think the relay was rated at 750 volts and it may have been a vacuum > type. That's a pretty husky reed relay but you are lucky it didn't arc. Peak-to-peak across that relay was higher than 750 volts if it was installed in a 1/2WL dipole. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226126 of rec.radio.amateur.antenna From: "Noon-Air" References: <44ae07f7$1$21440$afc38c87@news.optusnet.com.au> Subject: Re: looking for 2 metre mobile radio Date: Fri, 7 Jul 2006 10:33:46 -0500 Message-ID: <8bCdnWptE9ZG4zPZnZ2dnUVZ_vCdnZ2d@comcast.com> "Dennis Smith" wrote in message news:Cesrg.127414$dW3.8344@newssvr21.news.prodigy.com... > > "hamguy1" wrote in message > news:44ae07f7$1$21440$afc38c87@news.optusnet.com.au... >> hi there newgroups, i live in Australia im looking for either a yaesu >> kenwood icom or similar 2 meter for my mobile with dtmf mic preferably if >> anyone in the usa etc has 1 I would pay shipping to Australia .thanks in >> advance David nsw Australia . >> >> > Since you are in Australia and you probably do not have a Yaesu repair > facility close by I would stay away from their crap radios. > Their VHF/UHF mobiles are known for poor performance, poor reliability and > just crappy built quality. > I have owned radios from all the major manufactures and Kenwood, along > with > Icom are some of the best for the dollar. > > A "Bullet-Proof" mobile for the money ($269 US) is the Kenwood TM-G707A. > Good performance all around. I personally have never had a problem with *any* Yaesu radio that I currently own, or have owned in the past. I like their VHF, and dual band radios. I do however prefer Kenwood for HF. -n6ojn Article: 226127 of rec.radio.amateur.antenna From: "RST Engineering" References: <1152231331.422720.307440@s16g2000cws.googlegroups.com> <99qdnZchPq-pXjDZnZ2dnUVZ_oydnZ2d@adelphia.com> <1152242996.248159.241200@k73g2000cwa.googlegroups.com> <1152243473.901359.188510@m79g2000cwm.googlegroups.com> Subject: Re: AM-FM broadcast radio/antenna in truck? Message-ID: Date: Fri, 7 Jul 2006 08:36:51 -0700 That used to be true back in the old vacuum tube radio days. I don't believe low-C cable is being used these days ... just plain old 50/75 ohm coax. Jim wrote in message news:1152243473.901359.188510@m79g2000cwm.googlegroups.com... > The cable, btw, is designed to be very low capacitance. It's not > normal coax. > Article: 226128 of rec.radio.amateur.antenna From: Michael Coslo Subject: Re: looking for 2 metre mobile radio Date: Fri, 07 Jul 2006 13:26:05 -0400 Message-ID: References: <44ae07f7$1$21440$afc38c87@news.optusnet.com.au> Dennis Smith wrote: > "hamguy1" wrote in message > news:44ae07f7$1$21440$afc38c87@news.optusnet.com.au... >> hi there newgroups, i live in Australia im looking for either a yaesu >> kenwood icom or similar 2 meter for my mobile with dtmf mic preferably if >> anyone in the usa etc has 1 I would pay shipping to Australia .thanks in >> advance David nsw Australia . >> >> > Since you are in Australia and you probably do not have a Yaesu repair > facility close by I would stay away from their crap radios. > Their VHF/UHF mobiles are known for poor performance, poor reliability and > just crappy built quality. > I have owned radios from all the major manufactures and Kenwood, along with > Icom are some of the best for the dollar. > > A "Bullet-Proof" mobile for the money ($269 US) is the Kenwood TM-G707A. > Good performance all around. While others say the same about Kenwood radios.......... - 73 de Mike KB3EIA - Article: 226129 of rec.radio.amateur.antenna From: paggonzalez@gmail.com Subject: Reradiating RF signals from Satellital Modem Date: 7 Jul 2006 11:57:33 -0700 Message-ID: <1152298653.803900.283720@s13g2000cwa.googlegroups.com> I'm to install a satellital modem (Globalstar GSP-1620) in a place where there's no full direct sky visibility due to some metallic obstacules. To overcome this problem I'm thinking of placing a reradiating antenna or RF repeater over the top of the highest obstacule, facing the real GSP1620 antenna down on the ground. The GSP1620 has two RF frequencies, one for TX (1610-1625 Mhz) and another for RX (2484-2499 Mhz). Does anyone have any ideas on how to build up such reradiating antenna and/or RF repeater ? Is there any commercial product similar to this ? Thanks a lot. Pablo Article: 226130 of rec.radio.amateur.antenna From: Ron Walters Subject: Re: Optibeam References: <44ac9d91_1@news.iprimus.com.au> Message-ID: Date: Fri, 07 Jul 2006 19:31:42 GMT Zen wrote: > Ron Walters wrote: > >> Would appreciate comments relative to the Optibeam Log Periodic >> 14-30MHz antennas, I am also considering the SteppIR antenna but I am >> concerned with the mechanical and electric potential problems with >> that antenna. >> Getting on in age and tower climbing is s chore for me. Any >> suggestions or comments? >> >> Ron W4LDE > > The Only problem with the Optibeam is that their gain figures are > honest! I think if you look at Cebiks web page a at his Log periodic > models you also see how good LPDA's can be. > > What makes both the LPDA and the Optibeam look bad is the exagerated > gain claims from old antennas designs. We see LPDA's get tarred with > this brush daily, yet we know any decent lpda will just about perform > as well as any mutiband tribander. > > Whats amusing is that you see people time and time say that a 5 element > monoband will beat a 32 foot lpda by several S units. Yet we know that > a decent LPDA of this boom length will have a gain of about 8dbi versus > a monoband antennas gain of 10dbi! So you tell me where even 1 s units > gain comes from? > > What does not help the logs case is the dishonest manufacturers who blow > up their gain figures. People like Tennadyne, who seem to mix up dbi > with DBd. > > If it was my money and i wanted a small multiband beam antenna i would > buy the Optibeam, because 2 or 3 dbi does not mount to much on HF. I > would rather go for all band coverage with reliability versus something > like a Steppir which still is unproven. > > Optibeam have a nice model that covers from 40 through to 10 even 30 > meters. Now if you looked at the same size log needed to achieve that > with similar gain you see what a good design it is for ham radio. I dont > buy all the crap spun by Optibeams owner about LPDA;s and harmonics etc. > Harmonic suppression is a transmitter problem should never be the > antennas problem. If you have a receiver that cant handle a log because > of 2nd order IMD issues you have a crap receiver. > > Whats also interesting is that if you model a stack of LPDAs like N08D > has which is six logs on a 200 ft tower you see the gain is just about > equivalent to a monoband stack, and this is from 13 to 30 mhz. There is > some guy in W1 land who runs 2 big logs on a 100ft tower, if you heard > his signal from a distance you would be impressed. > > But dont worry too much about gain in any decent multiband beams like > the steppir and the optibeam. I beat stations with a 4 element steppir's > antennas with a high double extended zepp antenna. I would rather have > a low gain LPDA up at a 100 ft than a Steppir down on a 30ft pole. In > fact a lazy H at a decent height would perform just as well as most > small tribanders or a small 2 element cubical quad. > > You dont have to take mine or anyones word for it, just look at the > reliable models on Cebiks web page. You soon see that most of the gain > claims by optibeam. Force 12 is another company that has decent honest > figures. > > Zenki > Zen, Thank you for the comment and time it took to type it, very informative. Ron W4LDE Article: 226131 of rec.radio.amateur.antenna From: "Brian 2W0BDW" References: <44ae07f7$1$21440$afc38c87@news.optusnet.com.au> <8bCdnWptE9ZG4zPZnZ2dnUVZ_vCdnZ2d@comcast.com> Subject: Re: looking for 2 metre mobile radio Message-ID: Date: Fri, 07 Jul 2006 21:00:35 GMT "Noon-Air" wrote in message news:8bCdnWptE9ZG4zPZnZ2dnUVZ_vCdnZ2d@comcast.com... > > "Dennis Smith" wrote in message > news:Cesrg.127414$dW3.8344@newssvr21.news.prodigy.com... >> >> "hamguy1" wrote in message >> news:44ae07f7$1$21440$afc38c87@news.optusnet.com.au... >>> hi there newgroups, i live in Australia im looking for either a yaesu >>> kenwood icom or similar 2 meter for my mobile with dtmf mic preferably >>> if >>> anyone in the usa etc has 1 I would pay shipping to Australia .thanks in >>> advance David nsw Australia . >>> >>> >> Since you are in Australia and you probably do not have a Yaesu repair >> facility close by I would stay away from their crap radios. >> Their VHF/UHF mobiles are known for poor performance, poor reliability >> and >> just crappy built quality. >> I have owned radios from all the major manufactures and Kenwood, along >> with >> Icom are some of the best for the dollar. >> >> A "Bullet-Proof" mobile for the money ($269 US) is the Kenwood TM-G707A. >> Good performance all around. > > I personally have never had a problem with *any* Yaesu radio that I > currently own, or have owned in the past. I like their VHF, and dual band > radios. I do however prefer Kenwood for HF. > > -n6ojn I've had no problems with MOST of my Yaesu stuff, having sold it on quite soon after getting. However I did buy a NEW Yaesu scanner about 5 years ago. Back to dealer screwed up. NEW replacement supplied. That went back to dealer screwed up. NEW replacement supplied. This one sometimes throws a wobbly and needs a reset but at least it does work (at the moment) Never had a problem with Icom and their support here in UK is superb- email questions answered, copies of manuals supplied FREE for second hand equipment (when its not on their site). Can't fault 'em. Article: 226132 of rec.radio.amateur.antenna From: "amdx" References: <1152231331.422720.307440@s16g2000cws.googlegroups.com> <99qdnZchPq-pXjDZnZ2dnUVZ_oydnZ2d@adelphia.com> <1152242996.248159.241200@k73g2000cwa.googlegroups.com> <1152243473.901359.188510@m79g2000cwm.googlegroups.com> Subject: Re: AM-FM broadcast radio/antenna in truck? Date: Fri, 7 Jul 2006 16:36:43 -0500 Message-ID: wrote in message news:1152243473.901359.188510@m79g2000cwm.googlegroups.com... > The cable, btw, is designed to be very low capacitance. It's not > normal coax. > I measured a piece of auto radio coax, it was 8pf per foot. Article: 226133 of rec.radio.amateur.antenna Subject: E-field probe question From: chuck Date: Sat, 08 Jul 2006 10:38:18 -0400 Message-ID: <1152368991_21275@sp6iad.superfeed.net> A simple E-field probe for measuring near-field radiation (to verify compliance with FCC limits) is described at: http://www.kn4s.com/rf.html RF Safety (about halfway through the document) My question is this: Looking only at the two plates separated by 10 cm, what is the impedance the plates would present to a measuring device in the hf spectrum? Is there a simple way to calculate (estimate) the impedance? Is the charging circuit time constant a simple function of the resistivity of air? Ordinarily, a 10 megohm instrument would load such a probe excessively because the probe's impedance would be much higher than 10 megohms. Many thanks. Chuck NT3G ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 226134 of rec.radio.amateur.antenna From: "serge" Subject: MonstIr Steppir Problem Message-ID: Date: Sat, 8 Jul 2006 10:08:30 -0500 This is a multi-part message in MIME format. ------=_NextPart_000_000C_01C6A276.76BE9540 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable On 40M SWR looks OK, but on 20M and Up I have a high SWR problem, for example if I set 14.100 on the controller and TRCVR is on the same = freq. SWR will be more then 2.5:1 , to get a better swr on 14.100, I = have to go UP to 14.350 on the controller.=20 I can go to setup mode and change the driver lengths for the better SWR = , but not sure if this is a right way to correct this problem ... 73, Serge P.S.Anntena mounted at 110FT tower.=20 ------=_NextPart_000_000C_01C6A276.76BE9540 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

On 40M SWR = looks OK, but=20 on 20M and Up I have a high SWR problem,

for example=20 if I set 14.100 on the controller and TRCVR is on the same=20 freq. SWR will be more then 2.5:1 , to get a better swr on 14.100, = I have=20 to go UP to 14.350 on the controller.

I can go to = setup mode and=20 change the driver lengths for the better SWR , but not sure if this is a = right=20 way to correct this problem ...

73,
Serge

P.S.Anntena = mounted at=20 110FT tower.

------=_NextPart_000_000C_01C6A276.76BE9540-- Article: 226135 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: E-field probe question Date: Sat, 08 Jul 2006 09:09:02 -0700 Message-ID: References: <1152368991_21275@sp6iad.superfeed.net> On Sat, 08 Jul 2006 10:38:18 -0400, chuck wrote: >My question is this: > >Looking only at the two plates separated >by 10 cm, what is the impedance the >plates would present to a measuring >device in the hf spectrum? Hi Chuck, >From their own page: "the capacitance of its plates (1.8 pF)" There are enough dimensional clues to compute this yourself, however. >Is there a >simple way to calculate (estimate) the >impedance? Xc = 1/(2 · pi · f · C) >Is the charging circuit time >constant a simple function of the >resistivity of air? No. >Ordinarily, a 10 megohm instrument would >load such a probe excessively because >the probe's impedance would be much >higher than 10 megohms. The probe's resistance is what that is important, not its impedance (which is to say the reactance is immaterial except as a scaling factor as described). In that regard, the resistance is nearly infinite for all practical purposes. A 10 Meg Ohm meter would take 10 ms to discharge in comparison to 0.1 µs to recharge. The circuit is a clamping circuit (or peak detector) that automatically disconnects any load from the probe. The actual load is the sag in the charge to the capacitor. The ratio of charge/discharge insures that the volt meter is quite transparent to the probe - unless you are after an accuracy that borders on delusion. 73's Richard Clark, KB7QHC Article: 226136 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: E-field probe question Date: Sat, 08 Jul 2006 09:40:33 -0700 Message-ID: <3bmva2p1tl7kdjekjk3cl87bp29antppub@4ax.com> References: <1152368991_21275@sp6iad.superfeed.net> On Sat, 08 Jul 2006 09:09:02 -0700, Richard Clark wrote: >A 10 Meg Ohm meter would take 10 >ms to discharge in comparison to 0.1 µs to recharge. This was rather a hip-shot guesstimate where I put the cap on the wrong side of the isolation line's resistance. Anyway, there's still a significant charge/discharge ratio that isolates the meter. On the other hand, having called it a clamping circuit was a stretch too. It is in fact a rather sloppy design in that regard (it is self discharging) but this is not to say it lacks its intended utility. 73's Richard Clark, KB7QHC Article: 226137 of rec.radio.amateur.antenna Subject: Re: E-field probe question From: chuck Date: Sat, 08 Jul 2006 13:08:18 -0400 Message-ID: <1152377990_22095@sp6iad.superfeed.net> References: <1152368991_21275@sp6iad.superfeed.net> <3bmva2p1tl7kdjekjk3cl87bp29antppub@4ax.com> Richard Clark wrote: > On Sat, 08 Jul 2006 09:09:02 -0700, Richard Clark > wrote: > >> A 10 Meg Ohm meter would take 10 >> ms to discharge in comparison to 0.1 µs to recharge. > > This was rather a hip-shot guesstimate where I put the cap on the > wrong side of the isolation line's resistance. Anyway, there's still > a significant charge/discharge ratio that isolates the meter. > > On the other hand, having called it a clamping circuit was a stretch > too. It is in fact a rather sloppy design in that regard (it is self > discharging) but this is not to say it lacks its intended utility. > > 73's > Richard Clark, KB7QHC Thanks for the info, Richard. What I was looking for was information on the charging part of the circuit. It is not clear to me how or why the 1.8 pF should recharge from the E-field in 0.1 uS. The 0.1 uS time constant suggests a 5.6 megohm resistance in the charging circuit. From where does that resistance arise? Put differently, what limits the rate at which energy can be extracted from an E-field through a capacitance of 1.8 pF? Thanks. Chuck ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 226138 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1152245793.947530.36900@m79g2000cwm.googlegroups.com> <12aroqj2chrpu45@corp.supernews.com> <1152251047.124924.40880@m73g2000cwd.googlegroups.com> <9wsrg.205$2v.125@newssvr25.news.prodigy.net> <_pCdnSTtaaZR9DPZRVnyjQ@bt.com> Subject: Re: horiz. loop - triangle shape work? Date: Sat, 8 Jul 2006 18:13:16 +0100 Message-ID: > Reg Edwards wrote: > > No arcing problem that I ever detected. Transmitter was 100 watts. I > > think the relay was rated at 750 volts and it may have been a vacuum > > type. > > That's a pretty husky reed relay but you are lucky > it didn't arc. Peak-to-peak across that relay was > higher than 750 volts if it was installed in a 1/2WL > dipole. > -- > 73, Cecil ======================================== The voltage between the relay contacts, when open, can be considerably less that the voltage at the end of the live wire relative to ground. The capacitance between the open-circuit contacts of a reed relay is very small. And there is a larger capacitance between the two antenna wires on either side of the relay contacts. There is also capacitance between each of the two wires and ground. If the input impedance of the wire on the remote side of the relay is not low then we have a voltage divider. So the voltage which appears across the relay contacts can be considerably less than the volts between the live wire and ground. If I remember correctly, the relay was located more than 1/4-wavelength along an end-fed wire on the 160m band. There was a random but not very long length of wire on the far side of the relay. The antenna was only about 20 feet above ground, ie., quite lossy. The details of what experiments took place I can't remember. Perhaps something to do with input impedance measurements and treating antenna wires as transmission lines. If the open-circuit relay contacts did not arc over with 100 watts then it was more by design than good luck. ;o) I've just had a search round my junk boxes to see if I stll have the reed relay. It was built into a small plastic box with a few decoupling capacitors and 3 binding posts. But, unhappily, no signs of it. And my suggestion to operate a relay in an antenna wire via Radio Shack speaker wire stll holds good. ---- Regards, Reg, G4FGQ. Article: 226139 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: MonstIr Steppir Problem References: Message-ID: Date: Sat, 08 Jul 2006 18:10:51 GMT serge wrote: > for example if I set 14.100 on the controller and TRCVR is on the same freq. SWR will be more then 2.5:1 , to get a better swr on 14.100, I have to go UP to 14.350 on the controller. Lowest SWR doesn't usually occur at maximum gain or lowest F/B ratio. Have you contacted the manufacturer to see if it's really a problem? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226140 of rec.radio.amateur.antenna From: Me Subject: Re: Reradiating RF signals from Satellital Modem References: <1152298653.803900.283720@s13g2000cwa.googlegroups.com> Message-ID: Date: Sat, 08 Jul 2006 18:26:12 GMT In article <1152298653.803900.283720@s13g2000cwa.googlegroups.com>, paggonzalez@gmail.com wrote: > I'm to install a satellital modem (Globalstar GSP-1620) in a place > where there's no full direct sky visibility due to some metallic > obstacules. > To overcome this problem I'm thinking of placing a reradiating antenna > or RF repeater over the top of the highest obstacule, facing the real > GSP1620 antenna down on the ground. > > The GSP1620 has two RF frequencies, one for TX (1610-1625 Mhz) and > another for RX (2484-2499 Mhz). Does anyone have any ideas on how to > build up such reradiating antenna and/or RF repeater ? Is there any > commercial product similar to this ? > > Thanks a lot. > Pablo > You know just enough about RF to be DANGEROUS... Best leave the RF Engineering to someone who knows what they are doing....... By using any type of InBand Repeater, even if you did get enough signal in each direction, Your system REQUIRES that your Antenna Aiming be within about 500 ArcSeconds. How are you going to ensure that with some kind of thing in between. Best you put the dish out where you can see the appropriate location in the sky, the modem on the back of the dish, and then bring the baseband, or data, to the connected systems after that. Me Article: 226141 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: horiz. loop - triangle shape work? References: <1152245793.947530.36900@m79g2000cwm.googlegroups.com> <12aroqj2chrpu45@corp.supernews.com> <1152251047.124924.40880@m73g2000cwd.googlegroups.com> <9wsrg.205$2v.125@newssvr25.news.prodigy.net> <_pCdnSTtaaZR9DPZRVnyjQ@bt.com> Message-ID: Date: Sat, 08 Jul 2006 18:26:35 GMT Reg Edwards wrote: > If I remember correctly, the relay was located more than > 1/4-wavelength along an end-fed wire on the 160m band. Thanks Reg, that makes sense now. That's quite different >from breaking a 1/2WL loop in the middle using a relay. The voltages at each end of 1/2WL are 180 degrees out of phase so the relay has to handle double the voltage existing at the ends of the wires. A quick estimate of the voltages at the ends of a 1/2WL dipole being driven by 100 watts is 1000 volts RMS. The relay would have to stand off almost 3kV PTP. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226142 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: E-field probe question Date: Sat, 08 Jul 2006 13:29:35 -0700 Message-ID: <0o20b2dn690hqrkv01cblihkshgqrctka3@4ax.com> References: <1152368991_21275@sp6iad.superfeed.net> <3bmva2p1tl7kdjekjk3cl87bp29antppub@4ax.com> <1152377990_22095@sp6iad.superfeed.net> On Sat, 08 Jul 2006 13:08:18 -0400, chuck wrote: >Thanks for the info, Richard. > >What I was looking for was information >on the charging part of the circuit. It >is not clear to me how or why the 1.8 pF >should recharge from the E-field in 0.1 uS. Hi Chuck, As I said, an error with shooting from the hip. Besides, it is not the plates of the probe that are charging when compared to the 0.01µF cap, lead resistors, and meter. Rather, that probe capacitance (according to the author) is part of the reactance that is in series with the reactance of the diode. I'm not entirely convinced of the text's accuracy, but I'm not motivated to read it deeply either. The diode capacitance is a moving target and even its average is unsuitable for the analysis presented by the author. The 0.1 uS number was drawn from a hat for an average over the HF region when the series resistance is low - guaranteed for at least half a cycle when there is no stored charge. This returns us to the interpretation of the clamping circuit, but this interpretation remains tenuous. >Put differently, what limits the rate at >which energy can be extracted from an >E-field through a capacitance of 1.8 pF? The source resistance, which in this case is the field. To describe further embarks us upon the nature of extracting the signal's strength >from the field, and then on to matters of matching load to the source. Beyond that, it becomes an issue of efficiency. However, with respect to the proposed probe, matching and efficiency are not a concern. The point of the 0.01 capacitor (not the plate structure of the probe) is to store sufficient charge (undrained by the meter load) so as to effectively become an open circuit to power demand - for half a cycle at least in the design offered. The point of a probe is to not disturb the field (not take power, and to return as much energy as was extracted). 73's Richard Clark, KB7QHC Article: 226143 of rec.radio.amateur.antenna From: Owen Duffy Subject: Confidence limits for noise measurement Message-ID: Date: Sat, 08 Jul 2006 22:08:20 GMT I am trying to estimate the confidence limits for measurement of white noise passed through a limited band filter. In the first instance, can we consider the filter to be an ideal low pass filter. The noise voltage can be though of as a stream of instantaneous values with Gaussian distribution, mean of zero, and standard deviation equal to the RMS voltage. If I take samples of this waveform, I should be able to calculate the noise power (given the resistance). The noise power is proportional to the variance of these samples, and the constant of proportionality is 1/R. Shannon's Information Theory says to me that I need to sample the waveform at least at double the highest frequency of any component (the break point of the low pass filter). It seems to me that what I am doing in statistical terms is taking a limited set of samples and using it to estimate the population variance (and hence the noise power in a resistor). So, I can never be absolutely certain that my set of samples will give the same variance as the population that I sampled. I should expect that on repeated measurement of the same source, that there will be variation, and that a component of that variation is the chance selection of set of samples on which the estimate was based. It seems reasonable to assume that taking more samples should give me higher confidence that my estimate is closer to the real phenomena, the population variance. So, I am looking for a predictor of the relationship between sample variance (the "measured" power) and population variance (the "actual" power), number of samples, and confidence level. The statistic Chi^2=(N-1)*S^2/sigma^2 (where S^2 is the sample variance and sigma^2 is the population variance) seems a possible solution. The distribution of Chi^2 is well known. So I have plotted values for the confidence limits indicated by that approach, the plot is at http://www.vk1od.net/fsm/RmsConfidenceLimit01.gif . The x axis value of number of samples relates to the minimum number of samples to capture the information in the filtered output (in the sense of Shannon), ie bandwidth*2. It seems to me that this should also apply to a noise source that has been passed through a bandpass filter (with a lower break point >0), so long as the sampling rate is sufficient for the highest frequency, but that the number of samples used for the graph lookup is bandwidth*2. I understand that there are other sources of error, this note is focused on choice of appropriate number of samples (or integration time) to manage the variation in the sampling process due to chance. Am I on the right track? Comments appreciated. Owen PS: This is not entirely off topic, I am measuring ambient noise from a receiving system, and antenna performance assessment is the purpose. -- Article: 226144 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Confidence limits for noise measurement Date: Sat, 08 Jul 2006 17:10:34 -0700 Message-ID: References: On Sat, 08 Jul 2006 22:08:20 GMT, Owen Duffy wrote: > >I am trying to estimate the confidence limits for measurement of white >noise passed through a limited band filter. > >In the first instance, can we consider the filter to be an ideal low >pass filter. Hi Owen, This will possibly be your greatest source of error, the clipping of the spectrum. In Fourier Analysis, the operation is called "windowing" and there are a world of window shapes that offer either excellent frequency resolution at the cost of amplitude accuracy, or the t'other way 'round. Insofar as the window shape, this deviates >from an "ideal" filter response, but then an "ideal" filter response (infinite skirt) does not guarantee accuracy. Blackman and Tukey in their seminal work, "The Measurement of Power Spectra" (1958) assert that "a realistic white noise spectrum must be effectively band-limited by an asymptotic falloff at least as fast as 1/f²." Consider the discussion at: http://www.lds-group.com/docs/site_documents/AN014%20Understanding%20FFT%20Windows.pdf >Shannon's Information Theory says to me that I need to sample the >waveform at least at double the highest frequency of any component >(the break point of the low pass filter). That's Nyquist sampling rate at slightly more than double than Fmax. Shannon predicts the bit error rate for a signal to noise ratio. >It seems to me that what I am doing in statistical terms is taking a >limited set of samples and using it to estimate the population >variance (and hence the noise power in a resistor). Seeing that the RMS voltage is applied fully to the resistance, shouldn't that be signal + noise power in a resistor? The noise in this sense only describes the deviation from the distributions' shape. >So I have plotted values for the confidence limits indicated by that >approach, the plot is at >http://www.vk1od.net/fsm/RmsConfidenceLimit01.gif . The x axis value >of number of samples relates to the minimum number of samples to >capture the information in the filtered output (in the sense of >Shannon), ie bandwidth*2. When I've done brute force noise reduction through ever increasing samples, it always appeared to follow a square law relationship. >Am I on the right track? What are you using as a source of noise? 73's Richard Clark, KB7QHC Article: 226145 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Confidence limits for noise measurement Message-ID: <6ui0b2l0i65e7n49972j1s4i9gctjfp7q4@4ax.com> References: Date: Sun, 09 Jul 2006 00:44:26 GMT On Sat, 08 Jul 2006 17:10:34 -0700, Richard Clark wrote: >On Sat, 08 Jul 2006 22:08:20 GMT, Owen Duffy wrote: > >> >>I am trying to estimate the confidence limits for measurement of white >>noise passed through a limited band filter. >> >>In the first instance, can we consider the filter to be an ideal low >>pass filter. > >Hi Owen, > >This will possibly be your greatest source of error, the clipping of >the spectrum. In Fourier Analysis, the operation is called >"windowing" and there are a world of window shapes that offer either >excellent frequency resolution at the cost of amplitude accuracy, or >the t'other way 'round. Insofar as the window shape, this deviates >from an "ideal" filter response, but then an "ideal" filter response >(infinite skirt) does not guarantee accuracy. > >Blackman and Tukey in their seminal work, "The Measurement of Power >Spectra" (1958) assert that > "a realistic white noise spectrum must be effectively > band-limited by an asymptotic falloff at least as fast as 1/f²." > >Consider the discussion at: >http://www.lds-group.com/docs/site_documents/AN014%20Understanding%20FFT%20Windows.pdf > >>Shannon's Information Theory says to me that I need to sample the >>waveform at least at double the highest frequency of any component >>(the break point of the low pass filter). > >That's Nyquist sampling rate at slightly more than double than Fmax. >Shannon predicts the bit error rate for a signal to noise ratio. Ok. > >>It seems to me that what I am doing in statistical terms is taking a >>limited set of samples and using it to estimate the population >>variance (and hence the noise power in a resistor). > >Seeing that the RMS voltage is applied fully to the resistance, >shouldn't that be signal + noise power in a resistor? The noise in >this sense only describes the deviation from the distributions' shape. In this case, the KTB noise due to the loads own resistance is so small as to be insignificant and not require a correct to be applied. > >>So I have plotted values for the confidence limits indicated by that >>approach, the plot is at >>http://www.vk1od.net/fsm/RmsConfidenceLimit01.gif . The x axis value >>of number of samples relates to the minimum number of samples to >>capture the information in the filtered output (in the sense of >>Shannon), ie bandwidth*2. > >When I've done brute force noise reduction through ever increasing >samples, it always appeared to follow a square law relationship. I expected that, and the radioastronomy folk seem to work on that basis from Dicke's work, if I understand it correctly. > >>Am I on the right track? > >What are you using as a source of noise? Noise from the real world which I understand is not exactly white, but I figure that if I understand the behavior from a white noise point of view, the answer will be very close for noise that resembles white noise. The noise is audio output from an SSB receiver (operating below AGC gain compression threshold) that, if you like, is acting as a linear downconverter with a narrow pass band filter. Typically, the passband is 300-2400Hz. The sampling is done in a PC sound card at a rate of 11kHz. The application here is using these samples to synthesise a "true RMS voltmeter". The question is how many samples, or how long an integration time at a given bandwidth, is required to reduce the likely contribution of chance to the sampling process below, say 0.1dB, at a confidence level of, say 90% (in a two tailed test). Thanks for your response Richard. Owen -- Article: 226146 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Confidence limits for noise measurement Date: Sat, 08 Jul 2006 18:04:00 -0700 Message-ID: <4uk0b2h327ajspleq8e666klmejcqmp3j2@4ax.com> References: <6ui0b2l0i65e7n49972j1s4i9gctjfp7q4@4ax.com> On Sun, 09 Jul 2006 00:44:26 GMT, Owen Duffy wrote: >>>It seems to me that what I am doing in statistical terms is taking a >>>limited set of samples and using it to estimate the population >>>variance (and hence the noise power in a resistor). >> >>Seeing that the RMS voltage is applied fully to the resistance, >>shouldn't that be signal + noise power in a resistor? The noise in >>this sense only describes the deviation from the distributions' shape. > >In this case, the KTB noise due to the loads own resistance is so >small as to be insignificant and not require a correct to be applied. Hi Owen, I was not thinking of thermal noise (actually, I've been quite deeply involved in studying phonon interaction, but not to this purpose). Rather, I was offering that if you integrate under the curve of the gaussian distribution, and compare to the computed/measured noise power, then and only then through that difference would you resolve error. Of course, this may be a description of what you have already offered in previous discussion. >>What are you using as a source of noise? > >Noise from the real world which I understand is not exactly white, but >I figure that if I understand the behavior from a white noise point of >view, the answer will be very close for noise that resembles white >noise. > >The noise is audio output from an SSB receiver (operating below AGC >gain compression threshold) that, if you like, is acting as a linear >downconverter with a narrow pass band filter. Typically, the passband >is 300-2400Hz. The sampling is done in a PC sound card at a rate of >11kHz. The application here is using these samples to synthesise a >"true RMS voltmeter". I've used both biased Zeners and weakly illuminated Photomultiplier Tubes. The PMT doesn't offer much power, but it is flat out to the 100s of MHz. Another precision method is to load each output of a ring counter (as big a ring as possible) with a random selection of resistor values and feed them into a summing junction. This is especially useful in the AF region. 73's Richard Clark, KB7QHC Article: 226147 of rec.radio.amateur.antenna From: "Reg Edwards" References: Subject: Re: Confidence limits for noise measurement Date: Sun, 9 Jul 2006 02:26:44 +0100 Message-ID: Owen, I can't understand your problem. Could you condense it? I would just take every measurement to be correct at the time it was made and stop worrying about it. Have some faith in your measuring instruments. Variation in the presense of noise can be expected. If you want to be more accurate, sit and watch the meter for 30 seconds and make a mental average. If the noise statistics are stable then you will obtain the same answer five minutes later. This will give you confidence in the measurements. Which is what you are looking for. "Statistics" is amongst the most useful of the many branches of mathematics. But it comes to an end when trying to estimate the confidence to be placed in setting confidence limits. If you have a few months to spare, refer to the works of Sir Ronald Arthur Fisher, the greatest of all Statisticians. He was involved with genetics, medicine, agriculture, weather, engineering, etc. (You remind me of Gossett and the "t" distribution. Early in the 20th century Gossett was a chemist/mathematician working in the quality control department of the famous Guinness brewery in Dublin. In his work he derived the distribution of "t" which allowed confidence limits to be set up for the normal distribution based on the measurements on small samples themselves. He realised he had invented and mathematically proved a long-wanted, important, practical procedure. But his powerful employer could not allow chemistry and mathematics to be associated with yeast, hops and all the other natural flavoured ingredients in their beer so they barred him from publishing a learned paper on the subject under his own name. So he used the nom-de-plume "Student". Ever since then the name of his statistical distribution amongst scientists, engineers and everyone involved with statistics has been known as "Student's t". Guinness, untainted by Gossett, is still a popular drink in English and Irish pubs.) Student's "t" will very likely appear in the solution to your problem, whatever it is. ---- Reg. Article: 226148 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Confidence limits for noise measurement Message-ID: References: Date: Sun, 09 Jul 2006 02:32:34 GMT On Sun, 9 Jul 2006 02:26:44 +0100, "Reg Edwards" wrote: >Owen, I can't understand your problem. Could you condense it? I >would just take every measurement to be correct at the time it was >made and stop worrying about it. I am designing the instrument. I am exploring the number of samples required to reduce the effect of chance on the measurement result (in respect of the sampling issue) to an acceptable figure. > >Have some faith in your measuring instruments. Variation in the >presense of noise can be expected. If you want to be more accurate, >sit and watch the meter for 30 seconds and make a mental average. If >the noise statistics are stable then you will obtain the same answer >five minutes later. This will give you confidence in the measurements. >Which is what you are looking for. > >"Statistics" is amongst the most useful of the many branches of >mathematics. But it comes to an end when trying to estimate the >confidence to be placed in setting confidence limits. If you have a >few months to spare, refer to the works of Sir Ronald Arthur Fisher, >the greatest of all Statisticians. He was involved with genetics, >medicine, agriculture, weather, engineering, etc. > Somehow, I guessed this would turn to alcohol! >(You remind me of Gossett and the "t" distribution. Early in the 20th >century Gossett was a chemist/mathematician working in the quality >control department of the famous Guinness brewery in Dublin. In his >work he derived the distribution of "t" which allowed confidence >limits to be set up for the normal distribution based on the >measurements on small samples themselves. He realised he had invented >and mathematically proved a long-wanted, important, practical >procedure. But his powerful employer could not allow chemistry and >mathematics to be associated with yeast, hops and all the other >natural flavoured ingredients in their beer so they barred him from >publishing a learned paper on the subject under his own name. So he >used the nom-de-plume "Student". Ever since then the name of his >statistical distribution amongst scientists, engineers and everyone >involved with statistics has been known as "Student's t". > >Guinness, untainted by Gossett, is still a popular drink in English >and Irish pubs.) Well, despite my name and Irish father, there is not a skerrick of Irish in me, or Guiness for that matter. > >Student's "t" will very likely appear in the solution to your problem, >whatever it is. Student's t distribution is a probability distribution of the mean of a sample of normally distributed random numbers. The mean of noise is 0 (unless it contains DC, which is not noise). The Chi-square distribution (which I proposed in the original post) is the probability distribution of the variance of a sample of normally distributed random numbers. The variance of noise voltage is the RMS^2, or proportional to power, and so is of interest. Owen -- Article: 226149 of rec.radio.amateur.antenna From: ml Subject: cheep sweep? Message-ID: Date: Sun, 09 Jul 2006 02:42:51 GMT hi So if i buy some coax and want to do a 'sweep test to see if the connectors and cable is 'ok' i figured i'd buy a mfj or palastar etc seems most only do hf and mfj while up to 440 kinda ends there so i'd like to test up to at least 1.2g anyone know of any units like the above that are less then the megabucks pro gear? thanks Article: 226150 of rec.radio.amateur.antenna Date: Sun, 09 Jul 2006 02:55:35 +0000 From: Scott Subject: EZNEC Question Message-ID: Is there an upper frequency limit that EZNEC can calculate with? If so, how high can one go? Will it do reasonably well up to say 902 MHz? Scott N0EDV Article: 226151 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: EZNEC Question Date: Sat, 08 Jul 2006 20:07:41 -0700 Message-ID: <12b0snu32ufisd2@corp.supernews.com> References: No, there's no upper or lower frequency limit. However, EZNEC results are only as good as the model. As frequency increases it's increasingly difficult to make a model which adequately imitates the real antenna. Roy Lewallen, W7EL Scott wrote: > Is there an upper frequency limit that EZNEC can calculate with? If so, > how high can one go? Will it do reasonably well up to say 902 MHz? > > Scott > N0EDV Article: 226152 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <52ec8$44a69065$453d9423$8142@FUSE.NET> <44A6F80E.6010102@fuse.net> <59kea2tv6pma7sic35eufbijongfaa6cl3@4ax.com> <44ADCA31.2010307@fuse.net> Subject: Re: HFTA-ARRL-Space Message-ID: Date: Sat, 8 Jul 2006 21:47:41 -0700 "Richard Clark" wrote in message news:q11sa250d4j78318j07qn1ji058731dcmg@4ax.com... > Somewhere near the 15 meter band you can get the noise field from > Jupiter. Not exactly sentient, but still an exotic contact. > > 73's > Richard Clark, KB7QHC http://www.nasm.si.edu/ceps/etp/jupiter/jupimg/JUP_radio.gif Jupiter is a broadband radiator. Be glad it stays far away. Article: 226153 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <1152231331.422720.307440@s16g2000cws.googlegroups.com> <99qdnZchPq-pXjDZnZ2dnUVZ_oydnZ2d@adelphia.com> <1152242996.248159.241200@k73g2000cwa.googlegroups.com> <1152243473.901359.188510@m79g2000cwm.googlegroups.com> Subject: Re: AM-FM broadcast radio/antenna in truck? Message-ID: Date: Sat, 8 Jul 2006 22:18:30 -0700 "amdx" wrote in message news:adb65$44aed3e5$45011502$14278@KNOLOGY.NET... > > wrote in message > news:1152243473.901359.188510@m79g2000cwm.googlegroups.com... > > The cable, btw, is designed to be very low capacitance. It's not > > normal coax. > > > I measured a piece of auto radio coax, it was 8pf per foot. > > FWIW, my Dodge van's installed radio antenna went bad (open shield, way out of reach), so I put a Moto-to-BNC adapter on the back of the radio and dropped a pigtail of RG-58 down by the heater outlet. I connected my MFJ 2m/440 magmount to the radio via the pigtail. Works quite well. If I want to use it for ham radio, a couple of quick connector twists is all it takes. Added bonus: When driving out of town, away from strong signals and low overheads, I unscrew the stock MFJ whip, exchange it for a straight whip several feet long and get outstanding broadcast reception, both AM & FM. Article: 226154 of rec.radio.amateur.antenna From: "Mike, who else?" Subject: Re: looking for 2 metre mobile radio References: <44ae07f7$1$21440$afc38c87@news.optusnet.com.au> Message-ID: Date: Sun, 09 Jul 2006 05:27:55 GMT On Fri, 07 Jul 2006 17:06:41 +1000, hamguy1 wrote: > hi there newgroups, i live in australia im looking for either a yaesu > kenwood icom or similar 2 metre for my mobile with dtmf mic preferably if > anyone in the usa etc has 1 i would pay shipping to australia .thanks in > advance david nsw australia . www.ebay.com Article: 226155 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: cheep sweep? References: Message-ID: Date: Sun, 09 Jul 2006 00:11:43 -0500 Just for interest did you try my last suggestion with measuring power at source end load ends? The problem with cheap gear is of course accuracy. What kind of results are you looking for? You should be able to measure maybe 0.5dB problems using power measuring as previously mentioned. Cheers Bob ml wrote: > hi > > So if i buy some coax and want to do a 'sweep test to see if the > connectors and cable is 'ok' > > i figured i'd buy a mfj or palastar etc seems most only do hf and > mfj while up to 440 kinda ends there > > so i'd like to test up to at least 1.2g > > anyone know of any units like the above that are less then the > megabucks pro gear? > > thanks Article: 226156 of rec.radio.amateur.antenna From: Brian Howie Subject: Re: Voltage feeding a VHF yagi Date: Sun, 9 Jul 2006 09:23:59 +0100 Message-ID: References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> In message <1152164230.300210.322520@m79g2000cwm.googlegroups.com>, "n3ox.dan@gmail.com" writes >Anyone ever get around the VHF FM vertical yagi feedline routing >problem by voltage feeding the bottom of the driven element with a stub >like a J-pole? A quick EZNEC run seems to indicate that it's not a bad >idea. > >So it seems like it might work OK... but I wonder if anyone has >actually done it. Would you expect a coaxial stub to work better than >a parallel wire stub in terms of preserving the pattern of the yagi? > >Any commercial products doing this? There's an example of a 4ele 2m J-fed yagi in the MMANA files. It has a gain of 7dBd. Free space pattern is skewed up by 1 degree, but a real ground will do that anyway. I don't know of any commercial versions. Brian GM4DIJ -- Brian Howie Article: 226157 of rec.radio.amateur.antenna From: "Paul Willie Schleck" Subject: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Date: Sun, 9 Jul 2006 05:12:37 -0500 Message-ID: <4n6ql.jaf.19.1@news.alt.net> Warning. I, Paul W Schreck, blowgut of blowguts, and self-appointed moderator, will be monitoring these newsgroups for inappropriate statements, misuse of the groups, cross-posting and foul language and will be saving and archiving your comments for future use. Any future and wanton misuse of my name or callsign or forgeries thereof will be recorded as well. I will not hesitate to contact aeiou.com, wxyz, CBS, NBC, BBC or Altopia, or any other provider to turn you and your cohorts in for punitive action. While these groups are largely unmoderated, I am here to tell you that there is a new Sheriff in town, and the Sheriff is me. You have been warned. Conduct yourself accordingly or risk losing your ISP. Paul W. Schreck, Self Appointed Moderator Supreme, New Sheriff. Hissyfits@novia.nel www.blowguts.com Article: 226158 of rec.radio.amateur.antenna From: ml Subject: Re: cheep sweep? References: Message-ID: Date: Sun, 09 Jul 2006 11:57:25 GMT In article , Bob Bob wrote: > Just for interest did you try my last suggestion with measuring power at > source end load ends? > > The problem with cheap gear is of course accuracy. What kind of results > are you looking for? You should be able to measure maybe 0.5dB problems > using power measuring as previously mentioned. > > Cheers Bob > > ml wrote: > > hi > > > > So if i buy some coax and want to do a 'sweep test to see if the > > connectors and cable is 'ok' > > > > i figured i'd buy a mfj or palastar etc seems most only do hf and > > mfj while up to 440 kinda ends there > > > > so i'd like to test up to at least 1.2g > > > > anyone know of any units like the above that are less then the > > megabucks pro gear? > > > > thanks see my direct email, hope it's ok thanks Article: 226159 of rec.radio.amateur.antenna From: "H. Adam Stevens, NQ5H" Subject: Re: MonstIr Steppir Problem Date: Sun, 9 Jul 2006 08:51:06 -0500 Message-ID: <12b22ec1odi5v83@corp.supernews.com> References: This is a multi-part message in MIME format. ------=_NextPart_000_000D_01C6A334.D29EFEE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Serge Get in touch with SteppIR. They are very aggressive about customer service. SWR should be damn near 1:1 everywhere. My 4-el SteppiIR is 1:1 across all the bands. 73 H. NQ5H "serge" wrote in message = news:OTPrg.25701$8q.7015@dukeread08... On 40M SWR looks OK, but on 20M and Up I have a high SWR problem, for example if I set 14.100 on the controller and TRCVR is on the same = freq. SWR will be more then 2.5:1 , to get a better swr on 14.100, I = have to go UP to 14.350 on the controller.=20 I can go to setup mode and change the driver lengths for the better = SWR , but not sure if this is a right way to correct this problem ... 73, Serge P.S.Anntena mounted at 110FT tower.=20 ------=_NextPart_000_000D_01C6A334.D29EFEE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Serge
Get in touch with SteppIR.
They are very aggressive about customer = service.
SWR should be damn near 1:1=20 everywhere.
My 4-el SteppiIR is 1:1 across all the=20 bands.
73
H.
NQ5H
 
"serge" <aa8oo@cox.net> wrote in=20 message news:OTPrg.25701$8q.7015@duk= eread08...

On 40M SWR = looks OK, but=20 on 20M and Up I have a high SWR problem,

for example=20 if I set 14.100 on the controller and TRCVR is on the same=20 freq. SWR will be more then 2.5:1 , to get a better swr on = 14.100, I have=20 to go UP to 14.350 on the controller.

I can go to = setup mode=20 and change the driver lengths for the better SWR , but not sure if = this is a=20 right way to correct this problem ...

73,
Serge

P.S.Anntena = mounted at=20 110FT tower.

------=_NextPart_000_000D_01C6A334.D29EFEE0-- Article: 226160 of rec.radio.amateur.antenna Message-ID: <44B11051.5070708@w2agn.net> Date: Sun, 09 Jul 2006 10:18:57 -0400 From: "John L. Sielke" Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. References: <4n6ql.jaf.19.1@news.alt.net> Paul Willie Schleck wrote: > Warning. I, Paul W Schreck, blowgut of blowguts, and self-appointed > moderator, will be monitoring these newsgroups for inappropriate statements, > misuse of the groups, cross-posting and foul language and will be saving and > archiving your comments for future use. > > Any future and wanton misuse of my name or callsign or forgeries thereof > will be recorded as well. > > I will not hesitate to contact aeiou.com, wxyz, CBS, NBC, BBC or Altopia, or > any other provider to turn you and your cohorts in for punitive action. > > While these groups are largely unmoderated, I am here to tell you that there > is a new Sheriff in town, and the Sheriff is me. > > > > You have been warned. Conduct yourself accordingly or risk losing your ISP. > > > > Paul W. Schreck, Self Appointed Moderator Supreme, New Sheriff. > > Hissyfits@novia.nel > > www.blowguts.com > > > > > > Saving this post for a paper on "Mental Illness and Internet Usenet Groups." Classic paranoid schizophrenia with delusions of grandeur. Article: 226161 of rec.radio.amateur.antenna Date: Sun, 09 Jul 2006 10:19:43 -0400 From: "John L. Sielke" Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. References: <4n6ql.jaf.19.1@news.alt.net> Message-ID: Paul Willie Schleck wrote: > Warning. I, Paul W Schreck, blowgut of blowguts, and self-appointed > moderator, will be monitoring these newsgroups for inappropriate statements, > misuse of the groups, cross-posting and foul language and will be saving and > archiving your comments for future use. > > Any future and wanton misuse of my name or callsign or forgeries thereof > will be recorded as well. > > I will not hesitate to contact aeiou.com, wxyz, CBS, NBC, BBC or Altopia, or > any other provider to turn you and your cohorts in for punitive action. > > While these groups are largely unmoderated, I am here to tell you that there > is a new Sheriff in town, and the Sheriff is me. > > > > You have been warned. Conduct yourself accordingly or risk losing your ISP. > > > > Paul W. Schreck, Self Appointed Moderator Supreme, New Sheriff. > > Hissyfits@novia.nel > > www.blowguts.com > > > > > > Saving this post for a paper on "Mental Illness and Internet Usenet Groups." Classic paranoid schizophrenia with delusions of grandeur. Article: 226162 of rec.radio.amateur.antenna Message-ID: <44B11F25.1010108@fuse.net> Date: Sun, 09 Jul 2006 11:22:13 -0400 From: jawod Subject: Re: EZNEC Question References: <12b0snu32ufisd2@corp.supernews.com> Roy Lewallen wrote: > No, there's no upper or lower frequency limit. > > However, EZNEC results are only as good as the model. As frequency > increases it's increasingly difficult to make a model which adequately > imitates the real antenna. > > Roy Lewallen, W7EL > > Scott wrote: > >> Is there an upper frequency limit that EZNEC can calculate with? If >> so, how high can one go? Will it do reasonably well up to say 902 MHz? >> >> Scott >> N0EDV Roy, I just wanted to butt in to say that your EZNEC is a fine program. Just started playing with it (ARRL version). Very user friendly...and your "test drive" is phenomenal. I must say, since I left ham radio back in the late 70's, I am very surprised that antenna modeling is within the reach of someone of limited technical background like me. Great job! You've done a lot for my "new" favorite hobby. Thanks! John AB8WH PS, I will be purchasing the full program. Article: 226163 of rec.radio.amateur.antenna From: Win Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Date: Sun, 09 Jul 2006 11:04:51 -0500 Message-ID: References: <4n6ql.jaf.19.1@news.alt.net> >Warning. I, Paul W Schreck, blowgut of blowguts, This has to be a troll. It is cross posted to the world. And, short of "delete power," no one has ever moderated a group. Win, w0lz Article: 226164 of rec.radio.amateur.antenna From: Straydog Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Date: Sun, 9 Jul 2006 12:18:22 -0400 Message-ID: References: <4n6ql.jaf.19.1@news.alt.net> <44B11051.5070708@w2agn.net> On Sun, 9 Jul 2006, John L. Sielke wrote: > Paul Willie Schleck wrote: >> Warning. I, Paul W Schreck, blowgut of blowguts, and self-appointed >> moderator, will be monitoring these newsgroups for inappropriate statements, >> misuse of the groups, cross-posting and foul language and will be saving and >> archiving your comments for future use. >> >> Any future and wanton misuse of my name or callsign or forgeries thereof >> will be recorded as well. >> >> I will not hesitate to contact aeiou.com, wxyz, CBS, NBC, BBC or Altopia, or >> any other provider to turn you and your cohorts in for punitive action. >> >> While these groups are largely unmoderated, I am here to tell you that there >> is a new Sheriff in town, and the Sheriff is me. >> >> >> >> You have been warned. Conduct yourself accordingly or risk losing your ISP. >> >> >> >> Paul W. Schreck, Self Appointed Moderator Supreme, New Sheriff. >> >> Hissyfits@novia.nel >> >> www.blowguts.com >> >> >> >> >> >> > Saving this post for a paper on "Mental Illness and Internet Usenet Groups." > Classic paranoid schizophrenia with delusions of grandeur. > You forgot "Obsessive-Compulsive" Article: 226165 of rec.radio.amateur.antenna From: Mike Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Date: Sun, 09 Jul 2006 12:38:14 -0400 Message-ID: References: <4n6ql.jaf.19.1@news.alt.net> In article <4n6ql.jaf.19.1@news.alt.net>, "Paul Willie Schleck" wrote: > Warning. I, Paul W Schreck, blowgut of blowguts, and self-appointed > moderator, will be monitoring these newsgroups for inappropriate statements, > misuse of the groups, cross-posting and foul language and will be saving and > archiving your comments for future use. Hey Paul - go fuck yourself! > Any future and wanton misuse of my name or callsign or forgeries thereof > will be recorded as well. Hey Paul - go fuck yourself. > I will not hesitate to contact aeiou.com, wxyz, CBS, NBC, BBC or Altopia, or > any other provider to turn you and your cohorts in for punitive action. > > While these groups are largely unmoderated, I am here to tell you that there > is a new Sheriff in town, and the Sheriff is me. And the new sheriff is a dipshit. > You have been warned. Conduct yourself accordingly or risk losing your ISP. Hey Paul - go fuck yourself! Mike -- regarding Snit: "You are not flamed because you speak the truth, you are flamed because you are a hideous troll and keep disrupting the newsgroup." Andrew J. Brehm Article: 226166 of rec.radio.amateur.antenna From: "DrDeath" Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Date: Sun, 9 Jul 2006 12:02:33 -0500 Message-ID: <12b2dlbqp789c40@corp.supernews.com> References: <4n6ql.jaf.19.1@news.alt.net> "Mike" wrote in message news:no-24C013.12381409072006@news.supernews.com... (snipped) > regarding Snit: "You are not flamed because you speak the truth, > you are flamed because you are a hideous troll and keep disrupting > the newsgroup." Andrew J. Brehm How about snipping rec.radio.cb as we have troll problems of our own. Article: 226167 of rec.radio.amateur.antenna From: "Paladin" Subject: using a mobile mag mount in Living room.... Date: 9 Jul 2006 10:19:54 -0700 Message-ID: <1152465594.048986.16400@s13g2000cwa.googlegroups.com> Well.....this isn't my usual 2m set-up,BUT it is an extra set-up for the commute. I use the home/base set up in my living room at times for convience. I have been using a 2m hustler 5/8 wave,mag mount on my radiator cover with five watts to reach a local repeater. I can reach this repeater with my handie-talkie. For some UNKNOWN reason this mobile radio set up has been having a "squeal" on TRANSMIT. I can't figure out WHAT is causing this noise! It's starting to drive me crazy. Handie-talkie......no problems. My 2m shack radio...with an outdoor antenna,no problem. The SWR 's are fine. I've tried turning off and on the computor or the cable TV to see if those were the sources....no luck. I've moved the antenna around to different places on the rad. cover...?? Tried ferrite on the power leads.....used a battery,it dimished a little bit with the battery,but it is STILL THERE!!!!!! Am I doomed to either the Handie-talkie OR go uyp stairs to the shack to use the 2m's??? Sometimes I find a "signal"?,on the recieve meter,a small one, that CAN'T be squalched out either! darn crazy V-8000 I'm picking up something somewhere. It's ONLY on transmit. damn....I have to find out "WHY" maybe my radio needs a ground?........antenna AND RADIO. I feel lost with this one. paladin (feelin' old) Article: 226168 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. References: <4n6ql.jaf.19.1@news.alt.net> Message-ID: Date: Sun, 09 Jul 2006 17:49:41 GMT John L. Sielke wrote: > Saving this post for a paper on "Mental Illness and Internet Usenet Groups." > Classic paranoid schizophrenia with delusions of grandeur. Or a sick joke that is a forgery. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226169 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: EZNEC Question References: <12b0snu32ufisd2@corp.supernews.com> <44B11F25.1010108@fuse.net> Message-ID: Date: Sun, 09 Jul 2006 17:51:24 GMT jawod wrote: > I just wanted to butt in to say that your EZNEC is a fine program. ELNEC and EZNEC are two of my Elmers. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 226170 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: using a mobile mag mount in Living room.... Date: Sun, 09 Jul 2006 10:53:08 -0700 Message-ID: References: <1152465594.048986.16400@s13g2000cwa.googlegroups.com> ORIGINAL MESSAGE: On 9 Jul 2006 10:19:54 -0700, "Paladin" wrote: > It's ONLY on transmit. damn....I have to find out "WHY" maybe my >radio needs a ground?........antenna AND RADIO. I feel lost with >this one. ------------ REPLY SEPARATOR ------------ There are several possibilities on this kind of problem. Some things to try: 1. Put one or more snap-on ferrites on the coax. You may have an "RF in the shack" problem which is feeding back into the mike circuit. If this fixes it, you have an antenna problem, most likely a poor, i.e. non-resonant ground. 2. Add some more coax and get the TX farther away from the antenna. 3. Try it on a dummy load. Is the squeal still there? If so, a possible power supply problem. Good luck. 73, Bill W6WRT Article: 226171 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: using a mobile mag mount in Living room.... Message-ID: References: <1152465594.048986.16400@s13g2000cwa.googlegroups.com> Date: Sun, 09 Jul 2006 18:29:22 GMT On 9 Jul 2006 10:19:54 -0700, "Paladin" wrote: > Well.....this isn't my usual 2m set-up,BUT it is an extra set-up >for the commute. I use the >home/base set up in my living room at times for convience. I have been >using a 2m hustler 5/8 wave,mag mount on my radiator cover with five >watts to reach a local repeater. I can reach >this repeater with my handie-talkie. For some UNKNOWN reason this >mobile radio set up >has been having a "squeal" on TRANSMIT. I can't figure out WHAT is >causing this noise! >It's starting to drive me crazy. Handie-talkie......no problems. My 2m >shack radio...with an outdoor antenna,no problem. The SWR 's are fine. >I've tried turning off and on the computor or the cable TV to see if >those were the sources....no luck. I've moved the antenna around to >different places on the rad. cover...?? Tried ferrite on the power >leads.....used a battery,it >dimished a little bit with the battery,but it is STILL THERE!!!!!! > Am I doomed to either the Handie-talkie OR go uyp stairs to the >shack to use the 2m's??? Sometimes I find a "signal"?,on the recieve >meter,a small one, >that CAN'T be squalched out either! darn crazy V-8000 I'm >picking up something somewhere. > > It's ONLY on transmit. damn....I have to find out "WHY" maybe my >radio needs a ground?........antenna AND RADIO. I feel lost with >this one. > > paladin (feelin' old) Instead of the radiator, try one of the cooking pans/platters you might have in the kitchen. bob k5qwg Article: 226172 of rec.radio.amateur.antenna From: "Wayne" References: Subject: Re: DDRR antenna Message-ID: Date: Sun, 09 Jul 2006 18:33:09 GMT "JSF" wrote in message news:ypednZxCdphO3zjZnZ2dnUVZ_q2dnZ2d@comcast.com... > Anyone used one and if so how did it compare to a 1/4 wave. I build one for 2 meters some years ago. The element was 1/4 copper tubing with an air spaced variable at the end, and fed with a modified gamma match. The antenna was about 3 inches tall, and it fit on top of my van without hitting the garage on the way in. I did one set of rough comparisons between it and a 1/4 wave mag mount vertical. (A buddy gave readings from his S-meter) The vertical was better, but by less than 3 dB. This was not really a good test, but probably provided a valid assesment of which was better. However, the DDRR provided quite acceptable service into the local repeater, and I used the antenna until I sold the van. --Wayne Article: 226173 of rec.radio.amateur.antenna From: "David" Subject: Quarterwave vertical with radials Date: Sun, 9 Jul 2006 20:57:18 +0100 Message-ID: Can someone provide a full description of how a quarterwave vertical antenna with radials works? Length of radials is also a quarterwave. I find that many books give a good description of antennas like the Yagi, and then suddenly become very vague when describing the quarterwave vertical. Books refer to image theory where an image of the radiating element is produced by the radials, and show a spear shape going into the ground. Some say the radials are the other half of a dipole. What difference does it make if the radials are in free space or in the ground? Some articles claim that the radials tend not radiate because they cancel out, while other other articles claim that the radials simulate a ground plane and reflect the radio wave. Can you explain this contradiction? The vertical element is usually called the radiating element. How well do the radials radiate? The same magnitude of current flows into the vertical element as the radials, although the current into the radials is split. A normal ground plane is a large sheet of metal that reflects the radio wave emitted by the radiating element. If there are four radials, each a quarterwave long, do the radials form a ground plane? Or is there too much of a gap for them to form a ground plane? If the radials are disconnected and taken away, with the vertical quarterwave element still connected to centre conductor, do I still have a radiating element? What happens to the SWR? Article: 226174 of rec.radio.amateur.antenna From: Paul W. Schleck Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Date: 9 Jul 2006 15:13:03 -0500 Message-ID: <44b162e6$0$12378$540ea2cf@novia.net> References: <4n6ql.jaf.19.1@news.alt.net> In Cecil Moore writes: >John L. Sielke wrote: >> Saving this post for a paper on "Mental Illness and Internet Usenet Groups." >> Classic paranoid schizophrenia with delusions of grandeur. >Or a sick joke that is a forgery. >-- >73, Cecil http://www.qsl.net/w5dxp Yup, points to Cecil for realizing this. Based on similar turns of phrase in a private E-mail message sent to me recently (of the usual, unhinged, "I didn't ask to be welcomed to this newsgroup!" variety), I can say with great likelihood that the perpetrator of this forgery is the individual who posts on rec.radio.amateur.policy with the E-mail address "wussyroger@yahoo.com." I sent a complaint to alt.net and altopia.com in case they caught the poster in their logs. It seems that we've really, really hit a raw nerve here among the unbalanced trolls who populate rec.radio.amateur.policy. They very much seem to fear the prospect that a new, moderated discussion newsgroup for amateur radio stands a good chance of getting created, one that will leave them behind. I suspect that there will continue to be a storm of retaliatory forgeries for some time to come, at least through the fall. As I said previously, check the headers. If something appears to be from me, and is not from Novia/Newscene, then it's a forgery. Check also for misspellings, poor grammar, and obscene language. -- 73, Paul W. Schleck, K3FU pschleck@novia.net http://www.novia.net/~pschleck/ Finger pschleck@novia.net for PGP Public Key Article: 226175 of rec.radio.amateur.antenna From: "an_old_friend" Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Date: 9 Jul 2006 13:18:10 -0700 Message-ID: <1152476290.653398.214630@b28g2000cwb.googlegroups.com> References: <4n6ql.jaf.19.1@news.alt.net> Paul W. Schleck wrote: > In Cecil Moore writes: > > >John L. Sielke wrote: > >> Saving this post for a paper on "Mental Illness and Internet Usenet Groups." > >> Classic paranoid schizophrenia with delusions of grandeur. > > >Or a sick joke that is a forgery. > >-- > >73, Cecil http://www.qsl.net/w5dxp > > Yup, points to Cecil for realizing this. I realized it as well but the post (without regard to it's authorship is a good example of insane behavoir > > Based on similar turns of phrase in a private E-mail message sent to me > recently (of the usual, unhinged, "I didn't ask to be welcomed to this > newsgroup!" variety), I can say with great likelihood that the > perpetrator of this forgery is the individual who posts on > rec.radio.amateur.policy with the E-mail address "wussyroger@yahoo.com." as well winslutslit and various that that prclaim I a one or another type of nefarious felon > I sent a complaint to alt.net and altopia.com in case they caught the > poster in their logs. > > It seems that we've really, really hit a raw nerve here among the > unbalanced trolls who populate rec.radio.amateur.policy. They very much > seem to fear the prospect that a new, moderated discussion newsgroup for > amateur radio stands a good chance of getting created, one that will > leave them behind. I do hope it works out although I am and remain deeply dubious at the likely result being that much better than what the are a reaction to > > I suspect that there will continue to be a storm of retaliatory > forgeries for some time to come, at least through the fall. As I said > previously, check the headers. If something appears to be from me, and > is not from Novia/Newscene, then it's a forgery. Check also for > misspellings, poor grammar, and obscene language. the forgeries will conitinue likely forever (or until the net dies for some reason > > -- > 73, Paul W. Schleck, K3FU > pschleck@novia.net > http://www.novia.net/~pschleck/ > Finger pschleck@novia.net for PGP Public Key Article: 226176 of rec.radio.amateur.antenna From: "Reg Edwards" References: Subject: Re: Confidence limits for noise measurement Date: Sun, 9 Jul 2006 21:33:27 +0100 Message-ID: > I am designing the instrument. I am exploring the number of samples > required to reduce the effect of chance on the measurement result (in > respect of the sampling issue) to an acceptable figure. > ======================================== The first thing to do is calibrate the instrument against a standard noise source. Immediately, the uncertainty in the standard is transferred to the instrument - plus some more uncertainty due to the manner in which the standard and instrument are associated. Does the instrument read in watts, decibels, or what? The second thing to do is to be verbally and numerically more precise about "to reduce the effect of chance on the measurement result to an acceptable figure." At the outset you should define the acceptable figure. What effects? In what units is the acceptable figure? It is then not a difficult matter to decide the number of measurements, by taking samples, to give a predetermined level of confidence in the average or mean. But I have the feeling you are over-flogging the issue. You don't really have a problem. ---- Reg. Article: 226177 of rec.radio.amateur.antenna Date: Sun, 09 Jul 2006 16:46:47 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: Message-ID: David wrote: > Can someone provide a full description of how a quarterwave vertical antenna > with radials works? Length of radials is also a quarterwave. > > I find that many books give a good description of antennas like the Yagi, > and then suddenly become very vague when describing the quarterwave > vertical. Books > refer to image theory where an image of the radiating element is produced by > the radials, and show a spear shape going into the ground. Some say the > radials are the other half of a dipole. > > What difference does it make if the radials are in free space or in the > ground? Some articles claim that the radials tend not radiate because they > cancel out, while other other articles claim that the radials simulate a > ground plane and reflect the radio wave. Can you explain this contradiction? > > The vertical element is usually called the radiating element. How well do > the radials radiate? The same magnitude of current flows into the vertical > element as the radials, although the current into the radials is split. > > A normal ground plane is a large sheet of metal that reflects the radio wave > emitted by the radiating element. If there are four radials, each a > quarterwave long, do the radials form a ground plane? Or is there too much > of a gap for them to form a ground plane? > > If the radials are disconnected and taken away, with the vertical > quarterwave element still connected to centre conductor, do I still have a > radiating element? What happens to the SWR? Picture a half wave dipole, with a balanced feed. Two elements perform the radiation and there is zero voltage swing at the exact center of the dipole (though there is peak resonant current passing through the center). Now, cut that dipole exactly in half, and place a mirror at the half way point. Half of the balanced feed line can be replaced by an unbalanced (coaxial) feed line of half the impedance, since two of those, with their shields connected and the center conductors out of phase, would make a balanced feed line. The radiation from the quarter wave half of the dipole is reflected by the mirror to produce an an image of the missing half of the dipole. The radials at the end of the quarter wave dipole act as the mirror. This effect is pretty efficient as long as the radials are at least 1/4 wavelength long. Article: 226178 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Quarterwave vertical with radials Date: Sun, 09 Jul 2006 13:50:52 -0700 Message-ID: References: On Sun, 9 Jul 2006 20:57:18 +0100, "David" wrote: >Can someone provide a full description of how a quarterwave vertical antenna >with radials works? Length of radials is also a quarterwave. Hi David, Someone can, and someone already has, but that hasn't helped you has it? The following statements suggest so: >I find that many books give a good description of antennas like the Yagi, >and then suddenly become very vague when describing the quarterwave >vertical. It isn't vague, unless you've been saddled with poor references. On the other hand there is not much to say when you are working with elementary monopoles and dipoles. Yagis, in this sense, have much to be discussed. >Books >refer to image theory where an image of the radiating element is produced by >the radials, and show a spear shape going into the ground. Some say the >radials are the other half of a dipole. Radials being the "other half" simply reveals that the monopole (especially when elevated) is a vertical dipole. > >What difference does it make if the radials are in free space or in the >ground? About 3dB. >Some articles claim that the radials tend not radiate because they >cancel out, All parts of an antenna radiates, the radials' contributions cancel - at a distance. >while other other articles claim that the radials simulate a >ground plane and reflect the radio wave. Can you explain this contradiction? Poor references. The radials simply serve for drivepoint Z consideration (we already agree that their contribution to radiation cancel). For all practical purposes, the "ground plane" would have to extend out 5 to more wavelengths to affect the lobe characteristics of radiation. >The vertical element is usually called the radiating element. How well do >the radials radiate? Perfectly, or as well as the "radiator" presuming they all exhibit similar construction. >The same magnitude of current flows into the vertical >element as the radials, although the current into the radials is split. > >A normal ground plane is a large sheet of metal that reflects the radio wave >emitted by the radiating element. If there are four radials, each a >quarterwave long, do the radials form a ground plane? Or is there too much >of a gap for them to form a ground plane? They are simply not long enough, and certainly don't exhibit near the coverage (the gap you describe) as does a plane of metal (or seawater). >If the radials are disconnected and taken away, with the vertical >quarterwave element still connected to centre conductor, do I still have a >radiating element? A poor one, but given the wheel of fortune, the feedline could make up the difference. >What happens to the SWR? It usually goes ballistic, but again, with ground nearby, you could be heating worms and find the SWR at a comfortable value. 73's Richard Clark, KB7QHC Article: 226179 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: Message-ID: Date: Sun, 09 Jul 2006 21:20:17 GMT David wrote: > Can someone provide a full description of how a quarterwave vertical antenna > with radials works? Try the ARRL Antenna Book. In general, symetrical elevated radials don't radiate. In general, ground mounted radials are lossy. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226180 of rec.radio.amateur.antenna From: Woger Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Date: Sun, 09 Jul 2006 17:23:56 -0500 Message-ID: <4ohlq.hu3.19.1@news.alt.net> References: <4n6ql.jaf.19.1@news.alt.net> <44b162e6$0$12378$540ea2cf@novia.net> <1152476290.653398.214630@b28g2000cwb.googlegroups.com> It seems that we've really, really hit a raw nerve here among the > unbalanced trolls who populate rec.radio.amateur.policy. They very much > seem to fear the prospect that a new, moderated discussion newsgroup for > amateur radio stands a good chance of getting created, one that will > leave them behind. The raw nerve struck was yours, Paul. An ego is a terrible thing to offend, no? Article: 226181 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <4n6ql.jaf.19.1@news.alt.net> Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Message-ID: Date: Sun, 9 Jul 2006 15:07:48 -0700 "Paul Willie Schleck" wrote in message news:4n6ql.jaf.19.1@news.alt.net... > Warning. I, Paul W Schreck, blowgut of blowguts, and self-appointed > moderator, will be monitoring these newsgroups for inappropriate statements, < SNIP > > You have been warned. Conduct yourself accordingly or risk losing your ISP. Well, I'm safe. I don't have an ISP. (Several of my emptyheaded neighbors have them, so why do I need one?) Article: 226182 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <1152465594.048986.16400@s13g2000cwa.googlegroups.com> Subject: Re: using a mobile mag mount in Living room.... Message-ID: <8dfsg.1510$lv.267@fed1read12> Date: Sun, 9 Jul 2006 15:14:28 -0700 "Bob Miller" wrote in message news:cmi2b2lbel8i7q0511in0fjetk80sv50gt@4ax.com... > On 9 Jul 2006 10:19:54 -0700, "Paladin" wrote: > > > Well.....this isn't my usual 2m set-up,BUT it is an extra set-up > >for the commute. I use the > >home/base set up in my living room at times for convience. I have been > >using a 2m hustler 5/8 wave,mag mount on my radiator cover with five > >watts to reach a local repeater. I can reach > >this repeater with my handie-talkie. For some UNKNOWN reason this > >mobile radio set up > >has been having a "squeal" on TRANSMIT. I can't figure out WHAT is > >causing this noise! > >It's starting to drive me crazy. Handie-talkie......no problems. My 2m > >shack radio...with an outdoor antenna,no problem. The SWR 's are fine. > >I've tried turning off and on the computor or the cable TV to see if > >those were the sources....no luck. I've moved the antenna around to > >different places on the rad. cover...?? Tried ferrite on the power > >leads.....used a battery,it > >dimished a little bit with the battery,but it is STILL THERE!!!!!! > > Am I doomed to either the Handie-talkie OR go uyp stairs to the > >shack to use the 2m's??? Sometimes I find a "signal"?,on the recieve > >meter,a small one, > >that CAN'T be squalched out either! darn crazy V-8000 I'm > >picking up something somewhere. > > > > It's ONLY on transmit. damn....I have to find out "WHY" maybe my > >radio needs a ground?........antenna AND RADIO. I feel lost with > >this one. > > > > paladin (feelin' old) > > Instead of the radiator, try one of the cooking pans/platters you > might have in the kitchen. > > bob > k5qwg Yes, absolutely. You should get several square feet of conductive surface for a counterpoise -- sort of like the car roof the magmount is expecting. (I had good luck with a metal TV-tray.) Article: 226183 of rec.radio.amateur.antenna From: "Sal M. Onella" References: Subject: Re: Quarterwave vertical with radials Message-ID: Date: Sun, 9 Jul 2006 15:21:38 -0700 "John Popelish" wrote in message news:qsudnWCDYenB9CzZnZ2dnUVZ_vadnZ2d@adelphia.com... > David wrote: > > Can someone provide a full description of how a quarterwave vertical antenna > > with radials works? Length of radials is also a quarterwave. > > > > I find that many books give a good description of antennas like the Yagi, > > and then suddenly become very vague when describing the quarterwave > > vertical. Books > > refer to image theory where an image of the radiating element is produced by > > the radials, and show a spear shape going into the ground. Some say the > > radials are the other half of a dipole. > > > > What difference does it make if the radials are in free space or in the > > ground? Some articles claim that the radials tend not radiate because they > > cancel out, while other other articles claim that the radials simulate a > > ground plane and reflect the radio wave. Can you explain this contradiction? > > > > The vertical element is usually called the radiating element. How well do > > the radials radiate? The same magnitude of current flows into the vertical > > element as the radials, although the current into the radials is split. > > > > A normal ground plane is a large sheet of metal that reflects the radio wave > > emitted by the radiating element. If there are four radials, each a > > quarterwave long, do the radials form a ground plane? Or is there too much > > of a gap for them to form a ground plane? > > > > If the radials are disconnected and taken away, with the vertical > > quarterwave element still connected to centre conductor, do I still have a > > radiating element? What happens to the SWR? > > Picture a half wave dipole, with a balanced feed. Two elements > perform the radiation and there is zero voltage swing at the exact > center of the dipole (though there is peak resonant current passing > through the center). > > Now, cut that dipole exactly in half, and place a mirror at the half > way point. Half of the balanced feed line can be replaced by an > unbalanced (coaxial) feed line of half the impedance, since two of > those, with their shields connected and the center conductors out of > phase, would make a balanced feed line. > > The radiation from the quarter wave half of the dipole is reflected by > the mirror to produce an an image of the missing half of the dipole. > The radials at the end of the quarter wave dipole act as the mirror. > This effect is pretty efficient as long as the radials are at least > 1/4 wavelength long. Article: 226184 of rec.radio.amateur.antenna From: "Bob D." Subject: Computer alternative to Smith Chart? Date: Sun, 9 Jul 2006 17:25:02 -0500 Message-ID: I haven't used a Smith Chart in over 30 years, and to say the least, I'm a bit rusty. I'm thinking there must be computer programs that can do the calculations with values you just plugs in. Any recommendations? I'm specifically interested in finding the impedances of antenna whips much shorter than 1/4 wave. -- Bob D. ND9B Article: 226185 of rec.radio.amateur.antenna Date: Sun, 09 Jul 2006 17:35:28 -0500 From: Tom Ring Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. References: <4n6ql.jaf.19.1@news.alt.net> Message-ID: <44b184b0$0$1015$39cecf19@news.twtelecom.net> Cecil Moore wrote: > John L. Sielke wrote: > >> Saving this post for a paper on "Mental Illness and Internet Usenet >> Groups." >> Classic paranoid schizophrenia with delusions of grandeur. > > > Or a sick joke that is a forgery. Oh, it's a forgery alright, unless he doesn't know how to spell his own name. He spelled it correctly once, mispelled it twice, and none of the domains resolve. And the sender was not using his ISP, which is easy to find. A little attention to details, checking of headers, plus google goes a long way folks. tom K0TAR Article: 226186 of rec.radio.amateur.antenna Date: Sun, 09 Jul 2006 17:38:21 -0500 From: Tom Ring Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. References: <4n6ql.jaf.19.1@news.alt.net> Message-ID: <44b1855d$0$1015$39cecf19@news.twtelecom.net> Mike wrote: > In article <4n6ql.jaf.19.1@news.alt.net>, > > Hey Paul - go > > Mike > And coincidently, this post came from the same place as the forgery. Time to contact an ISP. And since I work at one.... tom K0TAR Article: 226187 of rec.radio.amateur.antenna From: "Sal M. Onella" References: Subject: Re: Quarterwave vertical with radials Message-ID: Date: Sun, 9 Jul 2006 15:38:45 -0700 "John Popelish" wrote in message news:qsudnWCDYenB9CzZnZ2dnUVZ_vadnZ2d@adelphia.com... \ > > Picture a half wave dipole, with a balanced feed. Two elements > perform the radiation and there is zero voltage swing at the exact > center of the dipole (though there is peak resonant current passing > through the center). > > Now, cut that dipole exactly in half, and place a mirror at the half > way point. Half of the balanced feed line can be replaced by an > unbalanced (coaxial) feed line of half the impedance, since two of > those, with their shields connected and the center conductors out of > phase, would make a balanced feed line. > > The radiation from the quarter wave half of the dipole is reflected by > the mirror to produce an an image of the missing half of the dipole. > The radials at the end of the quarter wave dipole act as the mirror. > This effect is pretty efficient as long as the radials are at least > 1/4 wavelength long. My experience with Navy UHF (225 - 400 MHz) antennas bears this out. There are two vertically polarized omni antennas that appear in great numbers: AT-150, which is a true dipole, fed with coax through an internal balun, and the AS-390, which is a quarter-wave whip with eight "spider-leg" radials. It is fed directly. They perform equally well and the system designer's choice is generally based on mounting considerations. There are over a dozen UHF antennas, some in stacked combinations called "stovepipes", but of the single-unit antennas, the AT-150 and the AS-390 are among the most common. Article: 226188 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Quarterwave vertical with radials Date: Sun, 09 Jul 2006 15:54:01 -0700 Message-ID: <12b328b1f0jgsd9@corp.supernews.com> References: David wrote: > Can someone provide a full description of how a quarterwave vertical antenna > with radials works? Length of radials is also a quarterwave. When you connect a source or feedline to this antenna, the same amount of current which flows into the vertical flows into the radials. First consider one which is well above the ground. The current in each pair of radials flows in physically opposite directions. So the radiation from the radials cancels completely at right angles to the radials, and nearly completely in other directions. The vertical acts like a dipole except with half the length and twice the current, resulting in the same pattern and field strength as a dipole. If the radials are buried, the current into the radials spreads into the ground. Current through the ground results in loss due to the ground's resistance. Therefore many radials are required to force the majority of current to flow in the wires rather than the ground. This is particularly important close to the vertical where the current density is high. > I find that many books give a good description of antennas like the Yagi, > and then suddenly become very vague when describing the quarterwave > vertical. Books > refer to image theory where an image of the radiating element is produced by > the radials, and show a spear shape going into the ground. Some say the > radials are the other half of a dipole. That's probably because the authors don't understand some fundamental principles, or else they oversimplify to the point where the explanation isn't correct. Radials are nothing more nor less than conductors carrying current, and radiate accordingly. But they're placed and fed so the radiation nearly cancels. > What difference does it make if the radials are in free space or in the > ground? Some articles claim that the radials tend not radiate because they > cancel out, while other other articles claim that the radials simulate a > ground plane and reflect the radio wave. Can you explain this contradiction? It's a lousy explanation of what's going on, written by someone who doesn't really understand. When the radiation from the vertical strikes the ground, it's reflected. If the ground were perfectly conductive, flat, and infinite in extent, it would be like a mirror. But real ground isn't any of these things, so a mirror is a very poor representation. The reflection from the ground causes the formation of a vertical radiation pattern which looks very different from what you'd get from a perfect, mirror-like ground, with the exception that salt water does approximate a mirror reasonably well. Except at high radiation angles, this reflection takes place well beyond any radials, so the radials don't contribute at all except at high angles. > The vertical element is usually called the radiating element. How well do > the radials radiate? The same magnitude of current flows into the vertical > element as the radials, although the current into the radials is split. Correct. See above. > A normal ground plane is a large sheet of metal that reflects the radio wave > emitted by the radiating element. "Normal"? Where have you seen an antenna mounted over a metal ground plane many wavelengths in diameter? Perhaps a UHF antenna in the middle of the top of a car, but that's about it. > If there are four radials, each a > quarterwave long, do the radials form a ground plane? Radials do not form a flat metal conductor many wavelengths in diameter, if that's what you're asking. And they don't reflect the radiation from the vertical, either. > Or is there too much > of a gap for them to form a ground plane? They're much too short to reflect the radiation. Or are there other properties you require for something to qualify as a "ground plane"? > If the radials are disconnected and taken away, with the vertical > quarterwave element still connected to centre conductor, do I still have a > radiating element? Yes. Whatever current you put into the element, an equal current flows elsewhere. If the element is connected to a coax transmission line, it flows down the outside of the coax, so the coax radiates just like the element. If you just plug it into a coax connector on a transmitter, the current flows out of the connector onto the outside of the transmitter, so it and the path to the Earth radiate just like the element. Current on a conductor creates radiation. It doesn't matter one bit whether you declare the conductor to be "ground", a "ground plane", or a "transmitter". What happens to the SWR? You now have an asymmetrical antenna. One "half" is the vertical and the other is whatever conductor the return current flows on. The SWR will almost certainly be different than it was for a typical ground plane antenna. Roy Lewallen, W7EL Article: 226189 of rec.radio.amateur.antenna From: "David" References: Subject: Re: Quarterwave vertical with radials Date: Sun, 9 Jul 2006 23:53:40 +0100 Message-ID: Image theory is for a perfect groundplane e.g. large area metal sheet. The wave emitted by the vertical radiating element is reflected by the ground plane. Image theory as I see it follows. Wave emitted by vertical element is the incident wave that hits ground plane, inducing currents in the ground plane. Currents flowing in skin depth of ground plane emit a wave of opposite polarity to cancel out the wave at the boundary of the ground plane, thus making the electric field in the ground plane zero. The wave of opposite polarity is the reflected wave. The reflected wave appears to be coming from an image antenna. Image theory is a mathematical model for solving antenna simulations where there is a monopole over a ground plane. How do the radials reflect the wave? If they are not a good enough ground plane because of the gap, how do they reflect? I cannot see the transition >from ground plane to radials, when looking at image theory. Article: 226190 of rec.radio.amateur.antenna Date: Sun, 09 Jul 2006 18:01:13 -0500 From: Tom Ring Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. References: <4n6ql.jaf.19.1@news.alt.net> Message-ID: <44b18ab9$0$1008$39cecf19@news.twtelecom.net> Mike wrote: > > Hey Paul - go fuck > > Mike > Actually, it's not the same source, but it's fun to mess with morons. So I'll have 2 separate people to call about tomorrow. Note that I said call. If you really want to get action from an ISP, email everything you can dig up to abuse@whatever_isp.com. Be sure to include full headers from the incident; if you don't, they will have nothing to work from. Then give a call to tech support and tell them what's going on, and where you sent the information. If they don't give you satisfaction, ask to speak to a manager or to engineering support. They will usually get you the person you need to resolve the problem. It's also a good idea to call during regular business hours for the time zone they are located in. tom K0TAR Article: 226191 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Confidence limits for noise measurement Message-ID: <2l03b2hffoicfkfmuvg1asin6fm55rvspp@4ax.com> References: Date: Sun, 09 Jul 2006 23:20:39 GMT On Sun, 9 Jul 2006 21:33:27 +0100, "Reg Edwards" wrote: > >> I am designing the instrument. I am exploring the number of samples >> required to reduce the effect of chance on the measurement result >(in >> respect of the sampling issue) to an acceptable figure. >> >======================================== >The first thing to do is calibrate the instrument against a standard >noise source. Immediately, the uncertainty in the standard is >transferred to the instrument - plus some more uncertainty due to the >manner in which the standard and instrument are associated. Reg, I think you have missed my point. Because of the random nature of white noise, an attempt to measure the noise source by sampling the noise for a short period introduces an error due to the sampling process. That sampling error is related to the quantity of "information" gathered by the sampling process, ie the length of "integration" or number of samples. The issue is not about absolute calibration, it is about one source of error in measuring a white noise source, and quantification of bounds on that error to a level of confidence. > >Does the instrument read in watts, decibels, or what? > >The second thing to do is to be verbally and numerically more precise >about "to reduce the effect of chance on the measurement result to an >acceptable figure." I am sorry if that is wordy, but I think it is precise in expressing the problem. To give a specific application, suppose that I want to do an receiver system performance test by comparing noise from one cosmic noise source with quiet sky, and I expect the variation with my G/T to be 0.5dB. > >At the outset you should define the acceptable figure. What effects? >In what units is the acceptable figure? The acceptable figure will depend on the application, I am trying to understand the principle. >It is then not a difficult matter to decide the number of >measurements, by taking samples, to give a predetermined level of >confidence in the average or mean. But I have the feeling you are >over-flogging the issue. You don't really have a problem. So, coming back to the application above, I note that successive measurements of the same white noise source passed through a limited bandwidth filter have variation from measurement to measurement, and that variation is related to the length of time that length of "integration" time or number of samples used for each measurement. In trying to understand this relationship, I explored the use of the Chi-square distribution as discussed in my initial posting. In looking for more information on that relationship, I found Dicke being quoted with an estimate of the sensitivity of a radiometer as the minimum detectable signal being the one in which the mean deflection of the output indicator is equal to the standard deviation of the fluctuations about the mean deflection of the indicator. He is quoted as saying: mean(delta-T)= (Beta * Tn) /( delta-v * t)^0.5 where delta-T is the minimum detectable signal; Beta is a constant of proportionality that depends on the receiver and is usually in the range 1 to 2; Tn is the receiving system noise temperature; delta-v is the pre-detection receiver bandwidth; and t is the post detection integration time constant. (I do not have a derivation of Dicke's formula.) This suggests that an estimate of the error (in dB) due to the sampling process is 10*log(1+Beta /( delta-v * t)^0.5). I have plotted the above expression at Beta=2 over the plots that I did based on the Chi-square distribution, they are at http://www.vk1od.net/fsm/RmsConfidenceLimit03.gif . You will see that the Dicke (Beta=2) line follows (ie it pretty much obscures by overwriting) my Chi-square based 95% confidence line. It appears that the two methods arrive at similar answers. Dicke's Beta seems to be determined empiracally. Varying Beta has the same effect as changing the confidence level in my Chi-square based estimator. Owen PS: Still remains relevant to antennas, I am measuring the performance of a receiver system, which includes the antenna and alll noise sources. -- Article: 226192 of rec.radio.amateur.antenna From: "David" References: Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 00:11:25 +0100 Message-ID: The contradiction over antenna radials continues. One posting says that the radials acts as a mirror and reflect the wave, another post says the radials do not reflect - that the radials are simply positioned so that the radiation from them cancels out. Article: 226193 of rec.radio.amateur.antenna From: Lloyd Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Date: Sun, 9 Jul 2006 23:24:26 +0000 (UTC) Message-ID: <3091217833.2458F8789@tarrnews.net> References: <4n6ql.jaf.19.1@news.alt.net> <44b1855d$0$1015$39cecf19@news.twtelecom.net> On Sun, 09 Jul 2006 17:38:21 -0500, Tom Ring wrote: > Mike wrote: > > > In article <4n6ql.jaf.19.1@news.alt.net>, > > > > Hey Paul - go > > > > Mike > > > > And coincidently, this post came from the same place as the forgery. > Time to contact an ISP. And since I work at one.... > > tom > K0TAR They're not getting their money's worth if that's the best you can do with headers. The post by "Mike" came from supernews.com, and that's not where the forgery originated. Maybe you can get a job at Burger King. Article: 226194 of rec.radio.amateur.antenna Subject: Re: E-field probe question From: chuck Date: Sun, 09 Jul 2006 19:46:53 -0400 Message-ID: <1152488297_32535@sp6iad.superfeed.net> References: <1152368991_21275@sp6iad.superfeed.net> <3bmva2p1tl7kdjekjk3cl87bp29antppub@4ax.com> <1152377990_22095@sp6iad.superfeed.net> <0o20b2dn690hqrkv01cblihkshgqrctka3@4ax.com> Thanks for the additional comments, Richard. The probe seems remarkable in being able to utilize a 10 megohm DMM to measure an RF field given that a DMM would not work at all to measure a static electric field. Static field measurements are almost always done with extremely high input resistance electrometers, fieldmeters, and field mills. All of these usually incorporate voltage follower op amps or something similar to keep the input resistance above 10 exp(13) ohms. Hooking up a DMM would quickly discharge any electrodes in the field. Thanks again. Chuck ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 226195 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Confidence limits for noise measurement Message-ID: References: <2l03b2hffoicfkfmuvg1asin6fm55rvspp@4ax.com> Date: Sun, 09 Jul 2006 23:56:00 GMT On Sun, 09 Jul 2006 23:20:39 GMT, Owen Duffy wrote: >mean(delta-T)= (Beta * Tn) /( delta-v * t)^0.5 > >where delta-T is the minimum detectable signal; Beta is a constant of >proportionality that depends on the receiver and is usually in the >range 1 to 2; Tn is the receiving system noise temperature; delta-v is >the pre-detection receiver bandwidth; and t is the post detection >integration time constant. > I should have mentioned that I don't understand why the Beta factor would vary from receiver to receiver. It seems that it was determined empirically. If the indicating instrument was a meter pointer observed by a person, perhaps Beta might have captured the observer effects more than the equipment. Owen -- Article: 226196 of rec.radio.amateur.antenna From: "Lloyd" Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Date: Sun, 9 Jul 2006 20:12:11 -0400 Message-ID: <4orcp.np0.19.1@news.alt.net> References: <4n6ql.jaf.19.1@news.alt.net> <44b162e6$0$12378$540ea2cf@novia.net> "Pompous Asshole Paul W. Schleck" whined & cried in a message news:44b162e6$0$12378$540ea2cf@novia.net... > > Based on similar turns of phrase ///drivel flushed/// Schleck + Moderated Group = HAHAHAHAHAHAHAHAH HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHA HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA............ Article: 226197 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Quarterwave vertical with radials Date: Sun, 09 Jul 2006 17:17:44 -0700 Message-ID: <9e63b25id6aaha8ipp7sih1p9qk34udl7o@4ax.com> References: On Mon, 10 Jul 2006 00:11:25 +0100, "David" wrote: >The contradiction over antenna radials continues. One posting says that the >radials acts as a mirror and reflect the wave, another post says the radials >do not reflect - that the radials are simply positioned so that the >radiation from them cancels out. Hi David, Well, this is not an opinion based outcome, and interpretation is even less forgiving. Radials that "act as a mirror" are fantasy for radial lengths less than 5 wavelengths at less than several hundred in count. Simple geometry and trig are suitable to observe this. Radials that "are simply positioned" certainly outnumber those that are not. A vertical with two radials is sufficient to do the job, and simply positioning them at 180° to one another is enough to insure their radiation from canceling at a distance. Now, when we regard the first claim in light of the second, it is amazing how much mirror-like quality those two radials have (which sort of puts the bronx cheer to the mirror claim). 73's Richard Clark, KB7QHC Article: 226198 of rec.radio.amateur.antenna From: Lloyd Subject: Novia Internetworking ToS? Date: Mon, 10 Jul 2006 00:25:57 +0000 (UTC) Message-ID: <881097833.2458F8789@tarrnews.net> References: <4n6ql.jaf.19.1@news.alt.net> <44b162e6$0$12378$540ea2cf@novia.net> On 9 Jul 2006 15:13:03 -0500, Paul W. Schleck wrote: [flushed] Your unsolicited email to new news group users seems to be in danger of violating novia.net's terms of service. To quote from http://www.novia.net/acceptable/ --(begin quote)-- 2. Sending any unsolicited electronic mail message: (i) to 25 or more electronic mail users, or (ii) to multiple electronic mail users in a manner which generates one or more complaints from such users. --(end quote)-- It's (ii) above which piques my interest. If it only takes ONE complaint from a mail recipient, aren't you in effect living in a glass house? If you're going to contact others' ISPs, perhaps you'd better take care that they don't become angry enough to contact your own ISP, at least until you clear up that possible problem with item 2(ii). You know what they say about people who live in glass houses. Article: 226199 of rec.radio.amateur.antenna From: kb9rqz_fruit@yahoo.com Subject: when this group was cool--Mon, Dec 1 2003 5:18 am Date: 9 Jul 2006 17:26:23 -0700 Message-ID: <1152491183.190332.58520@h48g2000cwc.googlegroups.com> Mon, Dec 1 2003 5:18 am Email: N...@dickmysuck.com (AntiKeyclown) Groups: rec.radio.cb Not yet ratedRating: show options Reply | Reply to Author | Forward | Print | Individual Message | Show original | Report Abuse | Find messages by this author shane_d_maud...@yahoo.com (Shane D. Maudiss) wrote in message ... > If my penis is erected, it=B4s a perfect antenna and I=B4ll receive > everything arounf hundreds of miles ! > My balls have perfect audio quality! > So use your balls for something useful, too !!! Yeah, like twathed does... Who can take a hard dick Suck out all the goo Stuff his nose up a butt crack And rim it real good too Twistedhed Oh Twistedhed does Twistedhed does cuz he mixes jizz with spit And thinks it tastes real good Who can bend it over And beg for throbbing dick And when he's finished gettin' pumped Turn around and lick a prick Twistedhed Oh Twistedhed does Twistedhed does cuz he mixes jizz with spit And thinks it tastes real good Twistedhed thinks Faggot keyclown twinks Are satisfiyng and delicious Talk about his childhood wishes He really blows those faggot bitches Who can hit a truckstop Announce that he'll be reamed Collect ten bucks a trucker And then suck up all the cream Twistedhed Twistedhed does Twistedhed does cuz he mixes jizz with spit And thinks it tastes real good Twistedhed thinks Faggot keyclown twinks Are satisfiyng and delicious Talk about his childhood wishes He really blows those faggot bitches Sorry Sammy...we could not resist... Article: 226200 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Quarterwave vertical with radials Date: Sun, 09 Jul 2006 17:50:37 -0700 Message-ID: References: On Sun, 9 Jul 2006 23:53:40 +0100, "David" wrote: >Image theory as I see it follows. Wave emitted by vertical element is the >incident wave that hits ground plane, inducing currents in the ground plane. Hi David, Well, given your repetition of "ground plane," be cautioned that is not one-and-the-same meaning for radials (even if they are called part of a ground plane antenna). 73's Richard Clark, KB7QHC Article: 226201 of rec.radio.amateur.antenna From: Paul W. Schleck Subject: Re: Novia Internetworking ToS? Date: 9 Jul 2006 20:19:02 -0500 Message-ID: <44b1aab0$0$12380$540ea2cf@novia.net> References: <4n6ql.jaf.19.1@news.alt.net> <44b162e6$0$12378$540ea2cf@novia.net> <881097833.2458F8789@tarrnews.net> In <881097833.2458F8789@tarrnews.net> Lloyd writes: >On 9 Jul 2006 15:13:03 -0500, Paul W. Schleck wrote: >[flushed] >Your unsolicited email to new news group users seems to be in danger >of violating novia.net's terms of service. To quote from >http://www.novia.net/acceptable/ >--(begin quote)-- >2. Sending any unsolicited electronic mail message: > (i) to 25 or more electronic mail users, or > (ii) to multiple electronic mail users in a manner which generates >one or more complaints from such users. >--(end quote)-- >It's (ii) above which piques my interest. If it only takes ONE >complaint from a mail recipient, aren't you in effect living in a >glass house? >If you're going to contact others' ISPs, perhaps you'd better take >care that they don't become angry enough to contact your own ISP, at >least until you clear up that possible problem with item 2(ii). >You know what they say about people who live in glass houses. I addressed this subject back in 1999: http://groups.google.com/group/rec.radio.amateur.misc/msg/26609a36708c7c5a I believe that you'll find the windows stronger than you think. -- Paul W. Schleck, K3FU pschleck@novia.net http://www.novia.net/~pschleck/ Finger pschleck@novia.net for PGP Public Key Article: 226202 of rec.radio.amateur.antenna Date: Sun, 09 Jul 2006 20:26:26 -0500 From: Tom Ring Subject: Re: Novia Internetworking ToS? References: <4n6ql.jaf.19.1@news.alt.net> <44b162e6$0$12378$540ea2cf@novia.net> <881097833.2458F8789@tarrnews.net> <44b1aab0$0$12380$540ea2cf@novia.net> Message-ID: <44b1acc2$0$6151$39cecf19@news.twtelecom.net> Paul W. Schleck wrote: > >>You know what they say about people who live in glass houses. > > > I addressed this subject back in 1999: > > http://groups.google.com/group/rec.radio.amateur.misc/msg/26609a36708c7c5a > > I believe that you'll find the windows stronger than you think. > > -- > Paul W. Schleck, K3FU > pschleck@novia.net > http://www.novia.net/~pschleck/ > Finger pschleck@novia.net for PGP Public Key Lloyd is a well known problem child. Emphasis on child. tom K0TAR Article: 226203 of rec.radio.amateur.antenna Message-ID: <44B1B316.5000406@fuse.net> Date: Sun, 09 Jul 2006 21:53:26 -0400 From: jawod Subject: Re: Quarterwave vertical with radials References: Cecil Moore wrote: > David wrote: > >> Can someone provide a full description of how a quarterwave vertical >> antenna >> with radials works? > > > Try the ARRL Antenna Book. In general, symetrical elevated > radials don't radiate. In general, ground mounted radials > are lossy. I second this. ARRL Antenna Book: Check pages 2-16 to 2-18 and "The Effects of Ground' which is Chapter 3. All the answers you need are there. Newsgroups can be helpful but sometimes only partly. A good text is your best friend. Learning this stuff can be a lot of fun. It can be frustrating, too. Good Luck, John AB8WH Article: 226204 of rec.radio.amateur.antenna From: pierred1@sympatico.ca Subject: Reflexion on ground and radials Date: 9 Jul 2006 19:17:01 -0700 Message-ID: <1152497821.479757.203660@75g2000cwc.googlegroups.com> Hi to all, >From the help file of EZNEC, I copy this sentence: ''The ground reflections which cause the low-angle pattern reflections take place farther from the antenna than most common radial ground systems extend, so ground radial systems have little or no effect on the ground reflection phenomenon.'' My question: Is this phenomenon dependent of the frequency? In other words, will the first reflexion point be farther away with lowering of the frequency or about at the same distance, independently of the wavelength**? **In that case, the ''long'' radials of AM broadcasting verticals 'may' also become reflectors... Thanks and 73 de Pierre VE2PID Article: 226205 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Computer alternative to Smith Chart? References: Message-ID: Date: Mon, 10 Jul 2006 02:21:37 GMT Bob D. wrote: > I haven't used a Smith Chart in over 30 years, and to say the least, I'm a > bit rusty. I'm thinking there must be computer programs that can do the > calculations with values you just plugs in. Any recommendations? I'm > specifically interested in finding the impedances of antenna whips much > shorter than 1/4 wave. The free demo version of EZNEC will probably do that. Available at: http://www.eznec.com -- 73, Cecil http://www.qsl.net/w5dxp Article: 226206 of rec.radio.amateur.antenna From: "David Thompson" References: Subject: Re: Horizontal HF Loop Message-ID: Date: Mon, 10 Jul 2006 02:36:15 GMT I put up a shielded link loop several years ago laying on the roof near the gutters with part goint to close trees in the front yard as a receiving antenna several years ago. It was something on the order of 180 feet long as written up by AB0X in a 1989 CQ. I had just gotten my Amp Supply LK 500NTC and was listening to a CX on 75. I thought I set it to RX on the antenna and transmit on my half square but I worked him on the shielded loop. He was only a few DB stronger on the half square. Did'nt burn the roof off but made sure I did not do that again HI. Dave K4JRB "Newman" wrote in message news:e8jti001t5p@enews2.newsguy.com... > Anyone here tried an HF horizonal loop built around residence? (either > attached under eaves or to trees very close by)... > Did it work? Affects of antenna on residence electronics and vice versa? > (100 watt TX) > Would plan to use on several bands w/antenna tuner & open wire feed. > Tnx for comments... > > Article: 226207 of rec.radio.amateur.antenna From: Butch Magee Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Date: Sun, 09 Jul 2006 22:53:09 -0500 Message-ID: <12b3jp78t2jsh84@corp.supernews.com> References: <4n6ql.jaf.19.1@news.alt.net> Outstanding my friend, shoulda done this sooner. Good show, I'm proud of you. This is a good thing for all of us. KF5DE Article: 226208 of rec.radio.amateur.antenna From: "Sal M. Onella" References: Subject: Re: Quarterwave vertical with radials Message-ID: Date: Sun, 9 Jul 2006 21:24:21 -0700 "David" wrote in message news:UNOdnZVbXoTO_CzZRVnyvg@bt.com... > A normal ground plane is a large sheet of metal that reflects the radio wave > emitted by the radiating element. If there are four radials, each a > quarterwave long, do the radials form a ground plane? Or is there too much > of a gap for them to form a ground plane? Effectively, yes. A metallic surface (your "sheet of metal") can be replaced by a partially metallic surface -- within limits. If you keep the size of any gap under 1/10 wavelength, the surface will appear solid. This I know from satellite reflector work. The use of four radials appears to be a compromise for using a solid surface, but it obviously works. The RF sees these radial wires and behaves like we want. I think adding more radials will always make a better counterpoise, but I also think you reach the point of diminishing returns pretty quickly. (We aren't the first ones to speculate about this, after all :-) Article: 226209 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Reflexion on ground and radials Date: Sun, 09 Jul 2006 21:54:15 -0700 Message-ID: <12b3nbnh82su223@corp.supernews.com> References: <1152497821.479757.203660@75g2000cwc.googlegroups.com> pierred1@sympatico.ca wrote: > Hi to all, > >>From the help file of EZNEC, I copy this sentence: > > ''The ground reflections which cause the low-angle pattern reflections > take place farther from the antenna than most common radial ground > systems extend, so ground radial systems have little or no effect on > the ground reflection phenomenon.'' > > My question: Is this phenomenon dependent of the frequency? In other > words, will the first reflexion point be farther away with lowering of > the frequency or about at the same distance, independently of the > wavelength**? > >**In that case, the ''long'' radials of AM broadcasting verticals 'may' > also become reflectors... > For a given antenna height and elevation angle, it's the same distance >from the antenna. Imagine yourself at some point on the antenna, say at the middle of a vertical antenna. Direct your gaze at an angle of 10 degrees below horizontal. Radiation traveling from the antenna at that angle will strike the ground at the point where your gaze does, and after reflection it will be going upward at an angle of 10 degrees above horizontal. The overall elevation pattern at 10 degrees elevation angle is formed by the sum of a direct ray going upward at 10 degrees and one going downward 10 degrees below horizontal, reflecting off the ground, and adding to it at a distant point. The lower the angle or the higher on the antenna you are, the farther the reflection point. Antenna programs repeat this process for every "segment", that is, points all along the antenna, to get the total field. So where does that reflection take place? Let's use your example of an AM broadcast antenna. Some broadcasters, I believe, use verticals which are around a half wavelength high. Suppose the frequency is 1 MHz, so the wavelength is 300 meters, and a half wave antenna would be about 150 meters high. Broadcast radials are, I think, around a half wavelength long. So the field from half way up the antenna would just strike the end of the radial field, using this simplified model, at a downward angle of arctan(75/150) ~ 26 degrees. Any radiation from the center of the vertical at an angle below 26 degrees would reflect beyond the radial field, so the elevation pattern for all angles below 26 degrees would be independent of the radial field. Likewise, radiation at 26 degrees from any portion of the antenna above half way up would strike the ground even farther away. Ironically, vertically polarized reflection at angles above this aren't too bad off plain dirt, so the radials don't help as much as you might think even at high angles. It's low angle reflections that really suffer when polarization is vertical, and those are the ones missing the radial field. This model is oversimplified, not taking into account the fact that the wavelength is large relative to some of the dimensions being considered or the considerable skin depth of the ground. The "NEC radial" option of NEC and EZNEC uses just this kind of analysis with the ground in the region of the radial field being assumed uniformly conductive, and I discourage its use. It's more accurate to model very slightly elevated radial wires where the fields from the wire currents make their true contribution. But when you do, you'll find that the radials still don't have much impact on the lower angle portion of the pattern. Roy Lewallen, W7EL Article: 226210 of rec.radio.amateur.antenna From: "an old friend" Subject: get help sicko Date: 9 Jul 2006 22:21:27 -0700 Message-ID: <1152508887.346753.236490@m79g2000cwm.googlegroups.com> References: <1152491183.190332.58520@h48g2000cwc.googlegroups.com> kb9rqz_fruit@yahoo.com wrote: get help sicko Article: 226211 of rec.radio.amateur.antenna From: "an old freind" Subject: Re: Novia Internetworking ToS? Date: 9 Jul 2006 22:27:38 -0700 Message-ID: <1152509258.138582.26210@s13g2000cwa.googlegroups.com> References: <4n6ql.jaf.19.1@news.alt.net> Lloyd wrote: > On 9 Jul 2006 15:13:03 -0500, Paul W. Schleck wrote: > > It's (ii) above which piques my interest. If it only takes ONE > complaint from a mail recipient, aren't you in effect living in a > glass house? you over look the notion that the materail involved has an impact it s the same mistake you make with my postings "lloyd" while you are that if I just went around posting "get help" for no reason I would likely lose my ISP access I don't do that and when you forward one of my posts the header contain links to the posts I am repling to, when I type get help in response to one of wismene diatribes accusing of all sorts of incest and other sex crimes with "get help" > > If you're going to contact others' ISPs, perhaps you'd better take > care that they don't become angry enough to contact your own ISP, at > least until you clear up that possible problem with item 2(ii). I also suspect that the fact he would complaining to the abuse and/or fraud depatments has something to do with response of his own provider > > You know what they say about people who live in glass houses. you look at the wrold in childish isolation Article: 226212 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1152497821.479757.203660@75g2000cwc.googlegroups.com> <12b3nbnh82su223@corp.supernews.com> Subject: Re: Reflexion on ground and radials Date: Mon, 10 Jul 2006 07:39:29 +0100 Message-ID: In daylight, with vertical LF and MF antennas, all radiation at an angle above 0 dgrees and that reflected from the ground, whuch is most of it, is wasted and generally unwanted. Only the groundwave is useful. At night a virtue is sometimes made out of a vice. "Roy Lewallen" wrote in message news:12b3nbnh82su223@corp.supernews.com... > pierred1@sympatico.ca wrote: > > Hi to all, > > > >>From the help file of EZNEC, I copy this sentence: > > > > ''The ground reflections which cause the low-angle pattern reflections > > take place farther from the antenna than most common radial ground > > systems extend, so ground radial systems have little or no effect on > > the ground reflection phenomenon.'' > > > > My question: Is this phenomenon dependent of the frequency? In other > > words, will the first reflexion point be farther away with lowering of > > the frequency or about at the same distance, independently of the > > wavelength**? > > > >**In that case, the ''long'' radials of AM broadcasting verticals 'may' > > also become reflectors... > > > > For a given antenna height and elevation angle, it's the same distance > from the antenna. > > Imagine yourself at some point on the antenna, say at the middle of a > vertical antenna. Direct your gaze at an angle of 10 degrees below > horizontal. Radiation traveling from the antenna at that angle will > strike the ground at the point where your gaze does, and after > reflection it will be going upward at an angle of 10 degrees above > horizontal. The overall elevation pattern at 10 degrees elevation angle > is formed by the sum of a direct ray going upward at 10 degrees and one > going downward 10 degrees below horizontal, reflecting off the ground, > and adding to it at a distant point. The lower the angle or the higher > on the antenna you are, the farther the reflection point. Antenna > programs repeat this process for every "segment", that is, points all > along the antenna, to get the total field. > > So where does that reflection take place? Let's use your example of an > AM broadcast antenna. Some broadcasters, I believe, use verticals which > are around a half wavelength high. Suppose the frequency is 1 MHz, so > the wavelength is 300 meters, and a half wave antenna would be about 150 > meters high. Broadcast radials are, I think, around a half wavelength > long. So the field from half way up the antenna would just strike the > end of the radial field, using this simplified model, at a downward > angle of arctan(75/150) ~ 26 degrees. Any radiation from the center of > the vertical at an angle below 26 degrees would reflect beyond the > radial field, so the elevation pattern for all angles below 26 degrees > would be independent of the radial field. Likewise, radiation at 26 > degrees from any portion of the antenna above half way up would strike > the ground even farther away. Ironically, vertically polarized > reflection at angles above this aren't too bad off plain dirt, so the > radials don't help as much as you might think even at high angles. It's > low angle reflections that really suffer when polarization is vertical, > and those are the ones missing the radial field. > > This model is oversimplified, not taking into account the fact that the > wavelength is large relative to some of the dimensions being considered > or the considerable skin depth of the ground. The "NEC radial" option of > NEC and EZNEC uses just this kind of analysis with the ground in the > region of the radial field being assumed uniformly conductive, and I > discourage its use. It's more accurate to model very slightly elevated > radial wires where the fields from the wire currents make their true > contribution. But when you do, you'll find that the radials still don't > have much impact on the lower angle portion of the pattern. > > Roy Lewallen, W7EL Article: 226213 of rec.radio.amateur.antenna From: "Reg Edwards" References: Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 07:53:25 +0100 Message-ID: "Cecil Moore" wrote > Try the ARRL Antenna Book. In general, symetrical elevated > radials don't radiate. In general, ground mounted radials > are lossy. ========================================== What everybody forgets about is that the velocity factor along ground-mounted radial wires is about half of the free-space value. Consequently, the 1/4-wave resonant length is crudely only half of the elevated value. On the other hand, the resonant length is very non-critical because Q is very small - Q is only 2 or 3 and is even smaller at the high end of the HF band. ---- Reg, G4FGQ Article: 226214 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 00:35:44 -0700 Message-ID: <12b40qh6jbg14b2@corp.supernews.com> References: Reg Edwards wrote: > > What everybody forgets about is that the velocity factor along > ground-mounted radial wires is about half of the free-space value. > > Consequently, the 1/4-wave resonant length is crudely only half of the > elevated value. > > On the other hand, the resonant length is very non-critical because Q > is very small - Q is only 2 or 3 and is even smaller at the high end > of the HF band. Actually, at HF and average ground, the velocity factor below the ground is about 1/4 to 1/5 the free space value. And no resonance at all is usually apparent because of the high loss. EZNEC isn't among the "everybody" who's forgotten it. Choose any real ground, open the Utilities menu and click Ground Info, and you'll see the velocity factor along with other information. But it's seldom of any practical use. Roy Lewallen, W7EL Article: 226216 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Quarterwave vertical with radials Date: 10 Jul 2006 04:01:01 -0700 Message-ID: <1152529261.147797.63180@b28g2000cwb.googlegroups.com> References: > Cecil Moore wrote: > > Try the ARRL Antenna Book. In general, symetrical elevated > > radials don't radiate. In general, ground mounted radials > > are lossy. >jawod wrote: > I second this. ARRL Antenna Book: > Check pages 2-16 to 2-18 and "The Effects of Ground' which is Chapter 3. > All the answers you need are there. > Newsgroups can be helpful but sometimes only partly. A good text is > your best friend. > Learning this stuff can be a lot of fun. It can be frustrating, too. Just last month, with four elevated 40 meter radials 6 feet high, the antenna was about 5 dB weaker than the very same antenna with 16 radials laid directly against soil. This basic result repeated at three different soil locations on three different bands, 160, 80, and 40, so it is not a fluke. In my last quick measurement on 7MHz: 16 long radials directly on the earth (no attempt to make resonant since they have very low Q) 0dB reference 8 long radials on the ground -1.3dB reference 4 long radials on the ground -3dB reference 4 resonant elevated radials at six feet -5.6dB reference 73 Tom Article: 226217 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Reflexion on ground and radials Date: 10 Jul 2006 04:20:32 -0700 Message-ID: <1152530432.290233.224280@s13g2000cwa.googlegroups.com> References: <1152497821.479757.203660@75g2000cwc.googlegroups.com> Reg Edwards wrote: > In daylight, with vertical LF and MF antennas, all radiation at an > angle above 0 dgrees and that reflected from the ground, whuch is most > of it, is wasted and generally unwanted. > > Only the groundwave is useful. > > At night a virtue is sometimes made out of a vice. While the above is generally true for broadcasting... I, like hundreds of others, can work 1000 miles or more during mid-day in winter on 160 meters. I, like many others, can work thousands of miles in mid morning or late afternoon. It isn't unusual to hear and work west coast stations that are 2000 miles away at 10 or 11 AM local time, and that sure isn't zero degree takeoff stuff. By the way the vast majority of AM BC stations use tower somewhere around 1/4 wl tall. There is nothing to be gained by going taller compared to the extra installation and upkeep expenses. AM BC stations used to use 5/8th wave verticals in early years of broadcasting, but they quickly learned that was actually a disadvantage because the earth around the antenna wasn't good enough to allow the full gain. All the extra height did was increase fading at modest distances. 73 Tom Article: 226218 of rec.radio.amateur.antenna From: Lloyd Subject: Re: Novia Internetworking ToS? Date: Mon, 10 Jul 2006 11:33:24 +0000 (UTC) Message-ID: <4491017833.2458F8789@tarrnews.net> References: <44b1aab0$0$12380$540ea2cf@novia.net> On 9 Jul 2006 20:19:02 -0500, Paul W. Schleck wrote: > > I addressed this subject back in 1999: > So you've been receiving complaints since 1999, yet have kept on sending unsolicited email (UE) anyway. What a stellar track record. Your "logic" for continuing your UE ("My ISP lets me do it.") is very similar to Mark Morgan's logic for continuing his ongoing flood of rrap. Will you stop the UE once you have created your own moderated group in which to play? Somehow I doubt it. Article: 226219 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: DDRR antenna Date: 10 Jul 2006 04:35:09 -0700 Message-ID: <1152531309.846243.230500@h48g2000cwc.googlegroups.com> References: Wayne wrote: > "JSF" wrote in message > news:ypednZxCdphO3zjZnZ2dnUVZ_q2dnZ2d@comcast.com... > > Anyone used one and if so how did it compare to a 1/4 wave. > > I build one for 2 meters some years ago. The element was 1/4 copper tubing > with an air spaced variable at the end, and fed with a modified gamma match. > The antenna was about 3 inches tall, and it fit on top of my van without > hitting the garage on the way in. That makes sense. For 80 meters we'd have an antenna 40 times taller and thicker, or a 10 inch diameter copper pipe element 10 feet above a metal plate a wavelength in radius as a groundplane, and only be about 3dB down from a 1/4 wl vertical. I'll run right out and build one. :-) 73 Tom Article: 226220 of rec.radio.amateur.antenna From: John Ferrell Subject: Re: Quarterwave vertical with radials Message-ID: References: <44B1B316.5000406@fuse.net> <1152529261.147797.63180@b28g2000cwb.googlegroups.com> Date: Mon, 10 Jul 2006 12:24:05 GMT Sometimes the more I learn the less I know. I have dabbled a lot along these lines in the last few months. I have determined my methods are faulty. When I compare two or more antennas for gain I have no means to measure the actual gain because I really don't know what the radiation pattern is in real life. However, comparing measured gains with calculated gains has given me more confidence in the EZNEC calculations. I have limited my test antenna to a 30 foot vertical with radials consisting of electrical extent ion cords connected in parallel stretched out on the ground. I seem to be manipulating the take off angle and the impedance of the feed by adding and subtracting these radials. The vertical seems to be more quiet (fewer signals) than a dipole but pretty much the same strength on those it hears. The reference dipole is the 40M section of my CushCraft A3S Beam at about 40 feet. The only certain conclusions I have made are that getting high confidence numbers about radials is a lot of work and probably beyond my resources. The ARRL Antenna Handbook and EZNEC are usually right. re: Usually right... If you lie to EZNEC it will lie right back to you with an even bigger lie. Be very careful with assumptions! The Antenna Handbook... There is still the unresolved issue of conjugate matching. I noted last week or so that a copy of Walter Maxwell's book that retailed for $19.95 went for about $75 on EBAY. John W8CCW On 10 Jul 2006 04:01:01 -0700, w8ji@akorn.net wrote: > > >> Cecil Moore wrote: >> > Try the ARRL Antenna Book. In general, symetrical elevated >> > radials don't radiate. In general, ground mounted radials >> > are lossy. >>jawod wrote: >> I second this. ARRL Antenna Book: >> Check pages 2-16 to 2-18 and "The Effects of Ground' which is Chapter 3. >> All the answers you need are there. >> Newsgroups can be helpful but sometimes only partly. A good text is >> your best friend. >> Learning this stuff can be a lot of fun. It can be frustrating, too. > >Just last month, with four elevated 40 meter radials 6 feet high, the >antenna was about 5 dB weaker than the very same antenna with 16 >radials laid directly against soil. > >This basic result repeated at three different soil locations on three >different bands, 160, 80, and 40, so it is not a fluke. > >In my last quick measurement on 7MHz: > >16 long radials directly on the earth (no attempt to make resonant >since they have very low Q) 0dB reference > >8 long radials on the ground -1.3dB reference > >4 long radials on the ground -3dB reference > >4 resonant elevated radials at six feet -5.6dB reference > >73 Tom John Ferrell W8CCW Article: 226221 of rec.radio.amateur.antenna From: Greg Rozelle Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. References: <4n6ql.jaf.19.1@news.alt.net> <44b1855d$0$1015$39cecf19@news.twtelecom.net> Message-ID: Date: Mon, 10 Jul 2006 12:32:35 GMT On Sun, 09 Jul 2006 17:38:21 -0500, Tom Ring wrote: >And coincidently, this post came from the same place as the forgery. >Time to contact an ISP. And since I work at one.... Pardon this reply and posting to six groups. To Paul W Schreck, Tom is right. Most isp care about $$ not what you say in a newsgroups. In the windows computer group, I was accused of being a troll because I didn't agree with others view point. My old isp never disconnected me. (My old isp did go out of Business) They will only do something if they get complaints from a lot of people not just one. Then sometimes it just a warning. No, I have never got a warning. Paul, no offensive is meant by this comment, You need to get a life. Just for the record. I never use cuss words. I don't intentionally make derogatory and/or rude comments. Greg Rozelle Disclaimer I have grammar problems. This post is not meant to be rude or derogatory to anyone or any company. Article: 226222 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <44B1B316.5000406@fuse.net> <1152529261.147797.63180@b28g2000cwb.googlegroups.com> Message-ID: Date: Mon, 10 Jul 2006 12:53:27 GMT w8ji@akorn.net wrote: > Just last month, with four elevated 40 meter radials 6 feet high, the > antenna was about 5 dB weaker than the very same antenna with 16 > radials laid directly against soil. Apples and oranges. The antennas to be compared should be identical except for height. 0.04WL on 40m can hardly be considered to be "elevated". To be considered to be truly elevated, the radials should be at least 1/2WL in the air. Please compare a ground mounted vertical with 4 radials to the same truly elevated-radial 40m vertical whose 4 radials are 70 feet in the air. Here's what EZNEC says about a 4 radial vertical on 40m. Radials one foot above ground: max gain is -0.34 dBi Radials 70 feet above ground: max gain is 2.51 dBi -- 73, Cecil http://www.qsl.net/w5dxp Article: 226223 of rec.radio.amateur.antenna From: Cecil Moore Subject: Induced signal? Message-ID: Date: Mon, 10 Jul 2006 13:17:39 GMT Here's a question overflowing from eHam.net and it's not a trick question. Assume that the radiating portion of a 40m vertical is made out of 33 feet of RG-213 and the braid is the radiator. The center conductor of the coax is left floating at both ends. How much RF voltage and/or current will be induced in that center wire when using the outside braid as the radiator for 100 watt operation? How much of an EM field can exist inside the coax braid? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226224 of rec.radio.amateur.antenna From: M.M. Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. Message-ID: References: <4n6ql.jaf.19.1@news.alt.net> <44B11051.5070708@w2agn.net> Date: Mon, 10 Jul 2006 13:55:46 GMT Since this OP is the new sheriff he will need to get some spy software for his computer to spy on the newsgroups. So he need to find and load SPY SHERIFF on his computer to control all of us offenders...M.M. On Sun, 09 Jul 2006 10:18:57 -0400, "John L. Sielke" wrote: >Paul Willie Schleck wrote: >> Warning. I, Paul W Schreck, blowgut of blowguts, and self-appointed >> moderator, will be monitoring these newsgroups for inappropriate statements, >> misuse of the groups, cross-posting and foul language and will be saving and >> archiving your comments for future use. >> >> Any future and wanton misuse of my name or callsign or forgeries thereof >> will be recorded as well. >> >> I will not hesitate to contact aeiou.com, wxyz, CBS, NBC, BBC or Altopia, or >> any other provider to turn you and your cohorts in for punitive action. >> >> While these groups are largely unmoderated, I am here to tell you that there >> is a new Sheriff in town, and the Sheriff is me. >> >> >> >> You have been warned. Conduct yourself accordingly or risk losing your ISP. >> >> >> >> Paul W. Schreck, Self Appointed Moderator Supreme, New Sheriff. >> >> Hissyfits@novia.nel >> >> www.blowguts.com >> >> >> >> >> >> >Saving this post for a paper on "Mental Illness and Internet Usenet Groups." >Classic paranoid schizophrenia with delusions of grandeur. Article: 226225 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 10:31:43 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: Message-ID: David wrote: > Image theory is for a perfect groundplane e.g. large area metal sheet. The > wave emitted by the vertical radiating element is reflected by the ground > plane. > > Image theory as I see it follows. Wave emitted by vertical element is the > incident wave that hits ground plane, inducing currents in the ground plane. > Currents flowing in skin depth of ground plane emit a wave of opposite > polarity to cancel out the wave at the boundary of the ground plane, thus > making the electric field in the ground plane zero. The wave of opposite > polarity is the reflected wave. The reflected wave appears to be coming from > an image antenna. Image theory is a mathematical model for solving antenna > simulations where there is a monopole over a ground plane. > > How do the radials reflect the wave? If they are not a good enough ground > plane because of the gap, how do they reflect? I cannot see the transition > from ground plane to radials, when looking at image theory. Picture a half wave disk of metal as the ground plane, producing the inverted image of the vertical. Then imagine thin radial slots spread around the vertical. Since these slots do not cross any current path that is needed to produce the image, they have little effect on the image. Widen those slots, and decrease the number of them, and eventually you get to a ground radial system with only a few radials. There has to be a transition point, where the radials are only a poor approximation of the original disk. The question is, how well must you approximate the disk to get a reasonable approximation of the far field radiation pattern it would have helped produce? Article: 226226 of rec.radio.amateur.antenna From: John - KD5YI Subject: Re: Quarterwave vertical with radials References: Message-ID: Date: Mon, 10 Jul 2006 14:37:41 GMT Sal M. Onella wrote: > "David" wrote in message > news:UNOdnZVbXoTO_CzZRVnyvg@bt.com... > >>A normal ground plane is a large sheet of metal that reflects the radio > > wave > >>emitted by the radiating element. If there are four radials, each a >>quarterwave long, do the radials form a ground plane? Or is there too much >>of a gap for them to form a ground plane? > > > Effectively, yes. > > A metallic surface (your "sheet of metal") can be replaced by a partially > metallic surface -- within limits. If you keep the size of any gap under > 1/10 wavelength, the surface will appear solid. This I know from satellite > reflector work. > > The use of four radials appears to be a compromise for using a solid > surface, but it obviously works. The RF sees these radial wires and behaves > like we want. I think adding more radials will always make a better > counterpoise, but I also think you reach the point of diminishing returns > pretty quickly. (We aren't the first ones to speculate about this, after > all :-) > > Actually, on elevated antennas (as in the usual VHF setup), just two quarter-wave radials 180 degrees apart is almost indistinguishable from 4 or more radials. EZNEC shows very little change in terminal impedance and pattern by removing two radials from a 4 radial ground plane. I once used copper tape on a window to make a ground plane vertical like that for 70cm. It worked very well. Cheers, John Article: 226227 of rec.radio.amateur.antenna From: paggonzalez@gmail.com Subject: Re: Reradiating RF signals from Satellital Modem Date: 10 Jul 2006 08:03:55 -0700 Message-ID: <1152543835.522559.53450@75g2000cwc.googlegroups.com> References: <1152298653.803900.283720@s13g2000cwa.googlegroups.com> Me ha escrito: > In article <1152298653.803900.283720@s13g2000cwa.googlegroups.com>, > paggonzalez@gmail.com wrote: > > > I'm to install a satellital modem (Globalstar GSP-1620) in a place > > where there's no full direct sky visibility due to some metallic > > obstacules. > > To overcome this problem I'm thinking of placing a reradiating antenna > > or RF repeater over the top of the highest obstacule, facing the real > > GSP1620 antenna down on the ground. > > > > The GSP1620 has two RF frequencies, one for TX (1610-1625 Mhz) and > > another for RX (2484-2499 Mhz). Does anyone have any ideas on how to > > build up such reradiating antenna and/or RF repeater ? Is there any > > commercial product similar to this ? > > > > Thanks a lot. > > Pablo > > > > You know just enough about RF to be DANGEROUS... Best leave the RF > Engineering to someone who knows what they are doing....... > By using any type of InBand Repeater, even if you did get enough signal > in each direction, Your system REQUIRES that your Antenna Aiming be > within about 500 ArcSeconds. How are you going to ensure that with > some kind of thing in between. Best you put the dish out where you can > see the appropriate location in the sky, the modem on the back of the > dish, and then bring the baseband, or data, to the connected systems > after that. > > Me Me, First of all, thanks a lot for your reply. Secondly, Globalstar constelation is NOT geostationary, thus the antenna is an omnidirectional one. Also, I do have the means to point the reradiating antenna and/or RF repeater towards the real omnidirectional one. Regards, Pablo Article: 226228 of rec.radio.amateur.antenna From: "an old freind" Subject: Re: Novia Internetworking ToS? Date: 10 Jul 2006 08:27:03 -0700 Message-ID: <1152545223.083088.260730@m79g2000cwm.googlegroups.com> References: <44b1aab0$0$12380$540ea2cf@novia.net> Lloyd wrote: > On 9 Jul 2006 20:19:02 -0500, Paul W. Schleck wrote: > > > > I addressed this subject back in 1999: > > > > So you've been receiving complaints since 1999, yet have kept on > sending unsolicited email (UE) anyway. > > What a stellar track record. > > Your "logic" for continuing your UE ("My ISP lets me do it.")........ stil have not learned much about the world have you? like reading >....... is very > similar to Mark Morgan's logic for continuing his ongoing flood of > rrap. Will you stop the UE once you have created your own moderated > group in which to play? he has offered a fact that may cuase to over come my misgiving'd aout moderation when the time come > > Somehow I doubt it. Article: 226229 of rec.radio.amateur.antenna From: "Newman" Subject: Re: Horizontal HF Loop Date: Mon, 10 Jul 2006 11:46:23 -0500 Message-ID: References: Tnx all who replied. Kevin, have decided to try to stay away from "looping" the house since it's guttered and other electronics inside. Now planning to try a triangular "loop" between 2 sides of house and a single support about 75' away - would make the total about 220' of wire, fed at one corner, about 30' AGL. (When it gets below 100 outside....) "Newman" wrote in message news:e8jti001t5p@enews2.newsguy.com... > Anyone here tried an HF horizonal loop built around residence? (either > attached under eaves or to trees very close by)... > Did it work? Affects of antenna on residence electronics and vice versa? > (100 watt TX) > Would plan to use on several bands w/antenna tuner & open wire feed. > Tnx for comments... > Article: 226230 of rec.radio.amateur.antenna From: nm5k@wt.net Subject: Re: Quarterwave vertical with radials Date: 10 Jul 2006 10:54:00 -0700 Message-ID: <1152554040.549559.53070@75g2000cwc.googlegroups.com> References: John - KD5YI wrote: > Actually, on elevated antennas (as in the usual VHF setup), just two > quarter-wave radials 180 degrees apart is almost indistinguishable from 4 or > more radials. Well, in theory yes, but in the real world , usually no. The reason being the decoupling. Four or more radials will decouple the line quite a bit better than two. I did tests adding radials to a VHF ground plane, and I saw improvement with each addition of radials I tried. Eight radials was a noticable improvement over four. But I always put it down to the improved decoupling of the feedline, rather than any big decrease in ground losses. I imagine if you used separate decoupling sections to avoid feeder radiation, the number of radials would matter little if any. As far as elevated ground planes vs ground mount...Cecil does have a point. It's common knowledge that a real low ground plane generally sucks. You need many, many, more radials to equal the ground loss of one at 1/2 wave up. While I don't doubt that the low ground plane was beaten by the ground mount in Tom's test, very few people actually run ground planes that low. If they do, they can count on me to berate them for it.. IE: I often jumped on Cecil for using one at appx 1/8 wave, and wondering why it didn't work too well. Thats too low, unless you have a lot of radials. In my observations comparing ground planes, you really need to be at least 1/4 wave in the air if you are going to use only four radials. Even then, thats not optimum. At 1/4 wave up, 8-12 radials is closer to optimum. Four radials at 1/4 wave is appx equal to about 60 on the ground. By "optimum", I mean equals 120 radials on the ground... Myself, I had a full length monopole on 40 m, with 32 ground radials. It was rarely much better than my dipole on medium long paths of say 1500 miles. When I elevated the antenna to 1/4 wave, and used only four radials, the performance was much better. Like day and night really. So I agree, if you run an elevated GP, it needs to be up in the air, or else you will need many radials. At 1/8 wave up, you need appx 60 radials to equal the 4 radials of the same antenna at 1/2 wave up. I've heard many a tale of people running low band ground planes, real low to the ground, and having bad results. But you won't hear those bad stories from the ones that run them at 1/4, 1/2 WL up. MK Article: 226231 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 11:01:50 -0700 Message-ID: <12b55ges6lfod74@corp.supernews.com> References: John Popelish wrote: > > Picture a half wave disk of metal as the ground plane, producing the > inverted image of the vertical. . . It appears that what I've been writing the past few days either isn't being read or isn't being believed. Among it is an explanation of why a "ground plane" doesn't produce an "image" of the vertical. Since you appear to continue to believe this, please explain the mechanism by which you think a half wave disk produces an "image" of the vertical. Roy Lewallen, W7EL Article: 226232 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: Reradiating RF signals from Satellital Modem References: <1152298653.803900.283720@s13g2000cwa.googlegroups.com> <1152543835.522559.53450@75g2000cwc.googlegroups.com> Message-ID: Date: Mon, 10 Jul 2006 12:23:10 -0500 Hi Pablo I was going to comment on this but didnt get around to it. I am surpised by your comment about the satellite system being LEO's rather than geostationary. Shows how much I have kept up with such systems! I see now it is the Globalstar/Iridium phone network, narrowband... I immediately discarded the idea of a passive repeater. The link budget that the system works on probably makes this a non starter. You can calculate it if you like using two LOS paths joined to each other. (ie take the RX level of the first link and feed it into the 2nd and subtract about another 3dB) I assume you have looked into and discarded running coax from the modem to antennas located at height. There will be major cable loss to consider at that frequency. You could of course use waveguide. You are thus constrained to a same frequency repeater unless you can modify how your box works. Same freq repeaters work provided you can get good isolation between the antenna systems. I havent done the link budget maths, but (for the downlink) placing an omni at height, connecting it to the input of a wideband preamp/amp design, running some cable length (say 20ft) to a directive (dish/gridpack) pointed down to your modem might do the trick. You only need enough total system gain to arrive at a similar signal level to what you'd get on your modem when it had an unobstructed sky view. It would be a good idea to use directive antenna(s) on your modem as well. You would do the same in reverse for the uplink (with a separate system) but keep in mind your amplifier has to handle a higher (input) signal level (but needs no difference in gain). There are probably brick amplifiers available from various manufacturers to do this, just having to pick the right frequency. I cant comment on the legality of this because I dont know. All the gain etc requirements should be pretty easy to calculate. What is most important is that the isolation "loss" of antenna placement must exceed that of the system gain, otherwise the amplifiers will take off (oscillate) and maybe cause major interference to not only your serverice but others as well. I was involved in mine comms on 400MHz some time ago. The system we put together had two back to back yagis maybe 20ft apart, a cavity and a wideband amp arranged on both sides of the tunnel. (One was tuned to the handheld TX freq, the other to the RX). We didnt have legality problems because it didnt radiate outside the tunnel. The only real issue we had was heat as the amplifier ran class A! I dont know whether all of this is worth the work. In fact I think that given Iridium/Globalstar uses a constellation of satellites the sky obstruction may not be a huge issue for you. I dont know enough about the density to make a judgement on this. I also noted (making a few web searches) that repeating system seems to be already available from Globalstar/Qualcomm themselves. I didnt look too deeply at it all... Good luck! Cheers Bob paggonzalez@gmail.com wrote: > > > Me ha escrito: > > >>In article <1152298653.803900.283720@s13g2000cwa.googlegroups.com>, >> paggonzalez@gmail.com wrote: >> >> >>>I'm to install a satellital modem (Globalstar GSP-1620) in a place >>>where there's no full direct sky visibility due to some metallic >>>obstacules. >>>To overcome this problem I'm thinking of placing a reradiating antenna >>>or RF repeater over the top of the highest obstacule, facing the real >>>GSP1620 antenna down on the ground. >>> >>>The GSP1620 has two RF frequencies, one for TX (1610-1625 Mhz) and >>>another for RX (2484-2499 Mhz). Does anyone have any ideas on how to >>>build up such reradiating antenna and/or RF repeater ? Is there any >>>commercial product similar to this ? >>> >>>Thanks a lot. >>>Pablo Article: 226233 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 11:10:37 -0700 Message-ID: <12b560umsqr7033@corp.supernews.com> References: John - KD5YI wrote: > > Actually, on elevated antennas (as in the usual VHF setup), just two > quarter-wave radials 180 degrees apart is almost indistinguishable from > 4 or more radials. EZNEC shows very little change in terminal impedance > and pattern by removing two radials from a 4 radial ground plane. > > I once used copper tape on a window to make a ground plane vertical like > that for 70cm. It worked very well. George Brown, the inventor of the ground plane antenna, found that only two radials were necessary. But when his company went to sell it, the marketing department decided that no one would buy a two-radial ground plane antenna in the belief that it would be omnidirectional. So they added two more to make it "look" more omnidirectional. The four-radial ground plane persists to this day. Just a few weeks ago, I designed what amounted to a two-radial ground plane antenna as part of a consulting job. It was made from copper tape on a Duroid dielectric material, a lot like the window antenna John described. An omnidirectional pattern was a requirement, and I was concerned that either the flatness of the tape or the presence of the dielectric might have some impact on the circularity of the pattern. So I had it tested at a local lab. It was the most circular pattern they'd ever seen, having about 1 dB maximum difference between any two directions. Roy Lewallen, W7EL Article: 226234 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: DDRR antenna Date: Mon, 10 Jul 2006 11:15:39 -0700 Message-ID: <12b56ab6bs0dn21@corp.supernews.com> References: <1152531309.846243.230500@h48g2000cwc.googlegroups.com> w8ji@akorn.net wrote: > Wayne wrote: >> "JSF" wrote in message >> news:ypednZxCdphO3zjZnZ2dnUVZ_q2dnZ2d@comcast.com... >>> Anyone used one and if so how did it compare to a 1/4 wave. >> I build one for 2 meters some years ago. The element was 1/4 copper tubing >> with an air spaced variable at the end, and fed with a modified gamma match. >> The antenna was about 3 inches tall, and it fit on top of my van without >> hitting the garage on the way in. > > That makes sense. > > For 80 meters we'd have an antenna 40 times taller and thicker, or a 10 > inch diameter copper pipe element 10 feet above a metal plate a > wavelength in radius as a groundplane, and only be about 3dB down from > a 1/4 wl vertical. > > I'll run right out and build one. :-) And wait'll you see the bandwidth! You'll be a busy guy running out and tweaking the capacitor every time you QSY. Roy Lewallen, W7EL Article: 226235 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 14:27:05 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> Message-ID: Roy Lewallen wrote: > John Popelish wrote: > >> >> Picture a half wave disk of metal as the ground plane, producing the >> inverted image of the vertical. . . > > > It appears that what I've been writing the past few days either isn't > being read or isn't being believed. Among it is an explanation of why a > "ground plane" doesn't produce an "image" of the vertical. > > Since you appear to continue to believe this, please explain the > mechanism by which you think a half wave disk produces an "image" of the > vertical. The disk forms an image by allowing the electric field lines to terminate perpendicular to the "mirror" surface on exactly the same lines as if they were heading toward a lower half of a dipole, while the radial currents in the "mirror" allow the magnetic field lines to encircle the monopole in the same pattern they would form if the missing half of the dipole were in position. This same pattern of electric and magnetic fields above the "mirror" produces (half of the) photons that the full dipole would have produced. A half wave diameter disk is about the minimum size "mirror" that will keep the field patterns close enough to those of the dipole to launch those photons. A larger disk would do better, but not a lot better. Article: 226236 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 14:29:56 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> Message-ID: Roy Lewallen wrote: > Just a few weeks ago, I designed what amounted to a two-radial ground > plane antenna as part of a consulting job. It was made from copper tape > on a Duroid dielectric material, a lot like the window antenna John > described. An omnidirectional pattern was a requirement, and I was > concerned that either the flatness of the tape or the presence of the > dielectric might have some impact on the circularity of the pattern. So > I had it tested at a local lab. It was the most circular pattern they'd > ever seen, having about 1 dB maximum difference between any two directions. Did this antenna include any provision to prevent current on the outside of the feed line? Which direction did the feed line exit the antenna? Article: 226237 of rec.radio.amateur.antenna From: "Lloyd" Subject: Re: Novia Internetworking ToS? Date: Mon, 10 Jul 2006 14:40:15 -0400 Message-ID: <4qsaa.fdu.19.1@news.alt.net> References: <4n6ql.jaf.19.1@news.alt.net> <44b162e6$0$12378$540ea2cf@novia.net> <881097833.2458F8789@tarrnews.net> <44b1aab0$0$12380$540ea2cf@novia.net> "Paul W. Schleck" wrote in message news:44b1aab0$0$12380$540ea2cf@novia.net... > In <881097833.2458F8789@tarrnews.net> Lloyd writes: > >>On 9 Jul 2006 15:13:03 -0500, Paul W. Schleck wrote: >>[flushed] Hey Schleck, wurt in the hood is you will receive support for your modurated group, if you write a 500 word essay on *humility* Deal? Article: 226238 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 11:39:03 -0700 Message-ID: <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> References: <12b55ges6lfod74@corp.supernews.com> On Mon, 10 Jul 2006 14:27:05 -0400, John Popelish wrote: > A larger disk would do better, but not a lot better. Hi John, In fact a larger disk will actually raise the launch angle - hardly a satisfactory mirror analogy. >the "mirror" produces (half of the) photons that the >full dipole would have produced. Photons? This is CecilBabble. Mirrors as "productive" sources of photons demonstrates the failure of analogies. 73's Richard Clark, KB7QHC Article: 226239 of rec.radio.amateur.antenna From: "an_old_friend" Subject: Re: Novia Internetworking ToS? Date: 10 Jul 2006 11:42:39 -0700 Message-ID: <1152556959.041800.74430@m79g2000cwm.googlegroups.com> References: <4n6ql.jaf.19.1@news.alt.net> Lloyd wrote: > "Paul W. Schleck" wrote in message > news:44b1aab0$0$12380$540ea2cf@novia.net... > > In <881097833.2458F8789@tarrnews.net> Lloyd writes: > > > >>On 9 Jul 2006 15:13:03 -0500, Paul W. Schleck wrote: > >>[flushed] > > > > Hey Schleck, > > wurt in the hood is you will receive support for your modurated > group, if you write a 500 word essay on *humility* Poor "lloyd" can't face his words > > Deal? Article: 226240 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: DDRR antenna Date: 10 Jul 2006 11:42:55 -0700 Message-ID: <1152556975.371988.111330@35g2000cwc.googlegroups.com> References: That's not high enough Q Roy. C'mon, I can only pass CW and PSK31 signals through mine without appreciable distortion. Who needs to use SSB? ... I did build one for 440MHz once though. Just a gap where the cap goes. It was one of the 2 ring types; about 1/2 inch spacing. and I could hit some repeaters with it... I could also hit some repeaters with one of those mini duckies too... not much to recommend the DDRR. I think if you're raring to build a vertically polarized, fairly low profile antenna and you have a big supply of fat copper pipe and a high voltage, high current, all welded split stator cap, you could build yourself a fierce magloop. Still have to retune every time you QSY... and I dunno... for similar construction quality and materials, how's the efficiency of the DDRR vs. the magloop? How low is the low radiation resistance of the DDRR? 73,Dan Article: 226241 of rec.radio.amateur.antenna From: You Subject: Re: Induced signal? References: Message-ID: Date: Mon, 10 Jul 2006 19:17:27 GMT In article , Cecil Moore wrote: > Here's a question overflowing from eHam.net and it's > not a trick question. > > Assume that the radiating portion of a 40m vertical > is made out of 33 feet of RG-213 and the braid is > the radiator. The center conductor of the coax is > left floating at both ends. How much RF voltage > and/or current will be induced in that center wire > when using the outside braid as the radiator for > 100 watt operation? How much of an EM field can > exist inside the coax braid? No RF Current, as the cenbter conductor is "Floating"...... There maybe some voltage buildup , but it will not have current flow untill the center conductor makes a circuit with something...... Article: 226242 of rec.radio.amateur.antenna From: "kb9rqz" Subject: Re: get help sicko Date: 10 Jul 2006 13:01:02 -0700 Message-ID: <1152561662.525517.201320@35g2000cwc.googlegroups.com> References: <1152491183.190332.58520@h48g2000cwc.googlegroups.com> I JACKING YOU an old friend wrote: > kb9rqz_fruit@yahoo.com wrote: > get help sicko Article: 226243 of rec.radio.amateur.antenna From: "an old friend" Subject: Re: get help sicko Date: 10 Jul 2006 13:05:38 -0700 Message-ID: <1152561938.675983.149330@m73g2000cwd.googlegroups.com> References: <1152491183.190332.58520@h48g2000cwc.googlegroups.com> kb9rqz wrote: get help sicko Article: 226244 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Induced signal? References: Message-ID: Date: Mon, 10 Jul 2006 21:12:19 GMT You wrote: > No RF Current, as the cenbter conductor is "Floating"...... > There maybe some voltage buildup , but it will not have current flow > untill the center conductor makes a circuit with something...... Well, that's essentially what I assumed. But W8JI disagrees so now I am not sure my assumption was correct. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226245 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> Message-ID: Date: Mon, 10 Jul 2006 21:16:22 GMT Tom Donaly wrote: > If you can bring yourself to think in terms of > current directions and far field superposition of waves, this > behavior shouldn't be that hard to understand. It's pretty easy to understand. Any two radials, 180 degrees apart and high enough, should theoretically cancel each other's radiation in the far field. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226246 of rec.radio.amateur.antenna From: "David" Subject: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 22:01:31 +0100 Message-ID: <8tudne3OaKF-Xi_ZRVny2w@bt.com> The theory behind the quarterwave vertical is the monopole above a ground plane, where the ground plane reflects the wave emitted by the vertical. The monopole is explained using image theory. In practice, the ground plane is replaced by radials. Do the radials reflect the wave then? The reflecting element on a Yagi manages to reflect most of the wave. The reflecting element on a Yagi is a parasitic element that has an impedance to cause the wave emitted by the driven element to flow in a particular direction. A Yagi normally has only one reflector. Although the reflector is in the near field of the Yagi, can a comparison be made with the radials of a quarterwave vertical antenna? The reflector on a Yagi is usually a thin tube with lots of air (gap) around it. Even though it occupies a small area, it still manages to reflect most of the wave. Yagi has a Front to Back ratio in dB. Radials can be tuned. Some antennas have loading coils in the radials. I notice that RF experts cannot agree on whether the radials reflect the wave or not. Antenna theory is often about wires and metallic items reflecting waves, and the phase of the reflected wave. The phase of the reflected wave can be constructive or destructive, affecting the impedance of the antenna. If an antenna is mounted too close to the ground, the reflected wave cancels out the emitted wave. Because a ground plane reflects the wave, the impedance of an antenna can vary with height. Parastic elements on a Yagi have a mutual impedance to each other. Would you regard the radials on a quarterwave vertical as having a mutual impedance? The radials increase the conductivity below the radiating element, decreasing ground losses. The radials are regarded as a finite or imperfect ground plane. References: "Antenna Theory and Design" by Warren Stutzman and Gary Thiele. pages 66 to 68. Practical monopole with radial wires to simulate a ground plane. "Antenna Engineering Handbook" by Richard C. Johnson. Radials suppress currents from flowing on outside of coax. p 28. If the ground is imperfect, the perfect reflected image is mutiplied by a complex ground reflection coefficient. The ground has a mutual impedance. "Antenna Theory" by Professor Constantine Balanis. Second Edition p 165. A ground plane formed by a perfect conductor completely reflects the wave. If the ground is finite i.e. not as conductive, it still reflects the wave but not as well. The conductivity determines the quality of the reflection. Article: 226247 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Induced signal? Date: 10 Jul 2006 14:39:38 -0700 Message-ID: <1152567578.553972.73090@p79g2000cwp.googlegroups.com> References: The center conductor isn't entirely floating. If the shield were closed at both ends, there would be no fields in the coax, but the coax center conductor at each end can have current induced on it from the outside world. I think you'd go about describing the coupling as being via "fringing fields" at the ends if you were to think of a free end of coax with fields in it radiating into space, I'm thinking of the reciprocal behavior... But this is a behavior where I'm imagining a differential-mode current existing to start with... I think the answer is highly influenced by the exact details of the end of the coax and where it is with respect to other objects... the coupling is very light and mostly to the shield at each end... and I think this makes it not entirely unlike just putting the shield wire and the center conductor wire in parallel in space with the ends tied together. I think current flows in the center conductor in phase with the current in the shield and there's very little differential mode current if any. Certainly I'm wrong, I'm going to think on it some more and try to figure out how wrong... What current flows in the center conductor if you short it to the shield with one wire at each end? What about if you do it with a solid metal cap ? 73, Dan Article: 226248 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 17:57:42 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> Message-ID: Richard Clark wrote: > On Mon, 10 Jul 2006 14:27:05 -0400, John Popelish > wrote: > > >>A larger disk would do better, but not a lot better. > > > Hi John, > > In fact a larger disk will actually raise the launch angle - hardly a > satisfactory mirror analogy. > > >>the "mirror" produces (half of the) photons that the >>full dipole would have produced. > > > Photons? This is CecilBabble. Mirrors as "productive" sources of > photons demonstrates the failure of analogies. Do you deny the photonic nature of radio waves? I just realized that the sentence you quoted s easily misinterpreted. When I said "the "mirror" produces (half of the) photons that the full dipole would have produced." I meant that half as many photons are produced, compared to the full dipole antenna that produces the same fields above the center line. I didn't mean that the mirror produces half of the total photons that are radiated. Article: 226249 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1152298653.803900.283720@s13g2000cwa.googlegroups.com> <1152543835.522559.53450@75g2000cwc.googlegroups.com> Subject: Re: Reradiating RF signals from Satellital Modem Date: Mon, 10 Jul 2006 22:46:45 +0100 Message-ID: What happens when the ground has very poor conductivity (very high resistivity), eg., arid desert sand with no rainfall. Incidentally, ground loss will be very small despite the very poor conductivity. ---- Reg. Article: 226250 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 18:00:07 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> Message-ID: Tom Donaly wrote: > John Popelish wrote: > >> Roy Lewallen wrote: >> >>> Just a few weeks ago, I designed what amounted to a two-radial ground >>> plane antenna as part of a consulting job. It was made from copper >>> tape on a Duroid dielectric material, a lot like the window antenna >>> John described. An omnidirectional pattern was a requirement, and I >>> was concerned that either the flatness of the tape or the presence of >>> the dielectric might have some impact on the circularity of the >>> pattern. So I had it tested at a local lab. It was the most circular >>> pattern they'd ever seen, having about 1 dB maximum difference >>> between any two directions. >> >> Did this antenna include any provision to prevent current on the >> outside of the feed line? >> >> Which direction did the feed line exit the antenna? > > I don't know about Roy's antenna, but this subject has come up before, > and at the time I made a two meter vertical ground plane with only two > radials. No matter how I oriented the antenna, radially, I got the same > signal strength on my field-strength meter. And yes, I took precautions > to make sure the feedline wasn't radiating. (Many ferrite beads at > strategic places on the feedline to the point that feedline radiation > was undetectable.) If you can bring yourself to think in terms of > current directions and far field superposition of waves, this > behavior shouldn't be that hard to understand. I agree. The point is, that I wonder if Roy's antenna feed had this precaution that reduces the radiation effect of the feed line, or if feed line radiation was part of the antenna. Article: 226251 of rec.radio.amateur.antenna From: "Reg Edwards" References: <12b560umsqr7033@corp.supernews.com> Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 22:59:05 +0100 Message-ID: George Brown was over precautious. Only one vertical radial is needed. There is no loss in efficiency. The radiation pattern remains sensibly the same. ---- Reg. Article: 226252 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 18:13:02 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> Message-ID: Reg Edwards wrote: > George Brown was over precautious. Only one vertical radial is > needed. There is no loss in efficiency. The radiation pattern remains > sensibly the same. 8-D Article: 226253 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 18:13:52 -0400 From: Dave Subject: Re: Induced signal? References: Message-ID: Cecil Moore wrote: > Here's a question overflowing from eHam.net and it's > not a trick question. > > Assume that the radiating portion of a 40m vertical > is made out of 33 feet of RG-213 and the braid is > the radiator. The center conductor of the coax is > left floating at both ends. How much RF voltage > and/or current will be induced in that center wire > when using the outside braid as the radiator for > 100 watt operation? How much of an EM field can > exist inside the coax braid? From my EM311 days: If I integrate the fields inside a short conducting cylinder, since there is no charge within the surface integral, there is no field within the cylinder. So the volume integral, ?E.dL = 0 = No voltage. But, this isn't the case! Now, if the cylinder is a 1/4 wavelength with distributed L and C ... ??? Since the cylinder is long compared to a wavelength, the distributed capacitance will couple a voltage to the inner conductor. The terminal impedance is open circuited [High Z] so no current flows. Conclusion: a standing wave exists on the inner conductor. It is caused by the distributed capacitance and the magnitude of the standing wave on the cylinder. Been away from EM for almost 50 years. I've probably forgotten too much. Article: 226254 of rec.radio.amateur.antenna From: "Reg Edwards" References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 23:15:48 +0100 Message-ID: "Cecil Moore" wrote > > It's pretty easy to understand. Any two radials, > 180 degrees apart and high enough, should theoretically > cancel each other's radiation in the far field. > -- > 73, Cecil ===================================== If they don't cancel-out each other in the near field then they don't cancel-out each other in the far field either. A pair of radials behave as a continuous dipole fed at its center via a single wire. And it radiates. A circular disk, diameter = 1/2 wavelength, fed at its centre radiates. But don't ask me what its radiation resistance is. It must be very low. ---- Reg. Article: 226255 of rec.radio.amateur.antenna From: "Dave" References: Subject: Re: Induced signal? Date: Mon, 10 Jul 2006 22:24:14 -0000 Message-ID: "Dave" wrote in message news:MfmdnRp7l-yCTC_ZnZ2dnUVZ_t-dnZ2d@comcast.com... > Cecil Moore wrote: > >> Here's a question overflowing from eHam.net and it's >> not a trick question. >> >> Assume that the radiating portion of a 40m vertical >> is made out of 33 feet of RG-213 and the braid is >> the radiator. The center conductor of the coax is >> left floating at both ends. How much RF voltage >> and/or current will be induced in that center wire >> when using the outside braid as the radiator for >> 100 watt operation? How much of an EM field can >> exist inside the coax braid? > > From my EM311 days: > > If I integrate the fields inside a short conducting cylinder, since there > is no charge within the surface integral, there is no field within the > cylinder. > > So the volume integral, ?E.dL = 0 = No voltage. But, this isn't the case! > > Now, if the cylinder is a 1/4 wavelength with distributed L and C ... ??? > > Since the cylinder is long compared to a wavelength, the distributed > capacitance will couple a voltage to the inner conductor. The terminal > impedance is open circuited [High Z] so no current flows. ah, but it isn't! remember, 1/4 wave long (more or less) makes the open at one end look like a short at the other end. there is also that distributed capacitance all along the length between the inner side of the shield and the center conductor... and also, the driving voltage at the ends are about 90 degrees out of phase, so there could be some non-trivial currents in the center conductor. > > Conclusion: a standing wave exists on the inner conductor. It is caused by > the distributed capacitance and the magnitude of the standing wave on the > cylinder. > > Been away from EM for almost 50 years. I've probably forgotten too much. > > > Article: 226256 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 15:35:38 -0700 Message-ID: <1nh5b25t1bq2k7bu7fj3q1ur5rkifjp203@4ax.com> References: <8tudne3OaKF-Xi_ZRVny2w@bt.com> On Mon, 10 Jul 2006 22:01:31 +0100, "David" wrote: >Do the radials reflect the wave then? Hi Dave, This has already been explained. >The reflecting element on a Yagi manages to reflect most of the wave. In fact, this is not true at all. Being a reflector is the name put to the chosen effect, the cause of the effect is re-radiation, not reflection. Reflection is merely the sum of phases that presents this effect. One must design, by choice, the "reflector" to exhibit a phase delay in its size, and in its distance from where the "reflection" is perceived. Anywhere else and there is no reflection whatever. Trying to abstract the action of a yagi reflector to a radial has its virtues, but explaining reflection is not one of them. >I notice that RF experts cannot agree on whether the radials reflect the >wave or not. Dr. Johnson (about 1780) offers a comment to errors of perception: "Johnson having argued for some time with a pertinacious gentleman; his opponent, who had talked in a very puzzling manner, happened to say, 'I don't understand you, Sir:' upon which Johnson observed, 'Sir, I have found you an argument; but I am not obliged to find you an understanding.' >Antenna theory is often about wires and metallic items reflecting waves, and >the phase of the reflected wave. The phase of the reflected wave can be >constructive or destructive, affecting the impedance of the antenna. If an >antenna is mounted too close to the ground, the reflected wave cancels out >the emitted wave. Um, yes. This catch-all combines many topics, but does not lead to a single conclusion however. For instance, your last sentence lacks too many qualifications to be true, and experience shows it is most certainly false. >Because a ground plane reflects the wave, the impedance of an antenna can >vary with height. Poor reading. A ground plane can completely absorb the wave, and the impedance of an antenna can vary with height. A ground plane can completely reflect the wave, and the impedance of an antenna can vary with height. It seems that the common factor is change of impedance, not the quality of reflection. Unfortunately I will disprove this utterly, below. The problem with your last statement is it separates "ground plane" >from ground (height), and then recombines it to a separate conclusion (reflection) elsewhere in this posting. The radials of an antenna's "ground plane" is not the same ground plane of reflection so often employed in analogies. >Parastic elements on a Yagi have a mutual impedance to each other. Would you >regard the radials on a quarterwave vertical as having a mutual impedance? > >The radials increase the conductivity below the radiating element, A paradox: As all elements of an antenna radiate, and radials are part of an antenna, and radiating; then the more interesting question is how can radials be below the radiating element? >decreasing ground losses. The radials are regarded as a finite or imperfect >ground plane. Much of these clippings from sources are disconnected from context; generally suitable only for a limited perspective; and often only for introduction to a fuller and more complete treatment. This is quite evident in their failure to support general conclusions. >"Antenna Theory" by Professor Constantine Balanis. Second Edition p 165. A >ground plane formed by a perfect conductor completely reflects the wave. If >the ground is finite i.e. not as conductive, it still reflects the wave but >not as well. The conductivity determines the quality of the reflection. Not to dismiss Costa out of hand, but an extremely poor conductor, saltwater, reflects nearly 100% of the RF radiated towards it. Turning it into a sea of copper would hardly improve the quality of reflection. Again, poor context reduces information to garbage. Let's consider this enigma further. I have a standard quarterwave AM antenna that has 48 radials arranged around it above an average ground that is in fact better than I can find here in Seattle. At resonance it exhibits a characteristic Z of Impedance = 36.15 - J 0.008024 ohms its peak radiation angle is well above the horizon at 22° if I were satisfied with 3dB poorer performance, I could depress that angle to 7°. Now, to test this ground plane (the earth ground that is, because nothing in the radial plane is going to change here), I put this antenna over poor ground (much like I would find in my back yard) and we find at resonance it exhibits a characteristic Z of Impedance = 33.62 - J 1.774 ohms Hmm, nothing to cause the Dept. of Homeland Security to bump the white house up from yellow alert. The launch angle climbed to 26°, all of four degrees. If I were satisfied with 3dB poorer performance, I could depress that angle to 9°. Now, I put this antenna over good ground (much like I would find floating in Puget Sound, just viewed out the window here) and we find at resonance it exhibits a characteristic Z of Impedance = 36.88 + J 7.924 ohms Hmm, hardly different from average ground. However, the launch angle dropped to 7° and I can drop that to 1° for a 1dB (not 3dB) hit. Clearly the "ground plane" out beyond the "radial plane" has made a substantial difference to the launch performance (the combination of all phases at a distance) and for all practical purposes absolutely no difference to its local operation at the drive point. So, with all respects to Costa, but your interpretation of his clipping leaves much to be desired. Clearly seawater is a miserable conductor compared to copper, and yet you would have to do a yeoman's chore of work to build a radial field over average earth to compare equally. 73's Richard Clark, KB7QHC p.s. and just to be perverse, let's raise this out of Puget Sound, out into outer space, well out of the way of the "ground plane" and discover, yes, we lose 3dB gain. So this further compounds the folly of platitudes that the ground plane, in regard to radials now, improves launch performance. Article: 226257 of rec.radio.amateur.antenna From: Ron Subject: Re: Quarterwave vertical with radials Date: 10 Jul 2006 18:43:35 EDT Message-ID: <44B2D9A7.6000703@yahoo.com> References: <1152554040.549559.53070@75g2000cwc.googlegroups.com> Ok I am getting confused. You are saying that a groundplane will not work as good a a ground mounted vertical ? At what angle are you talking about? Are you more interested in working 500 miles or 6,000 miles? Ron Article: 226258 of rec.radio.amateur.antenna From: "Jerry Martes" References: <1152298653.803900.283720@s13g2000cwa.googlegroups.com> Subject: Re: Reradiating RF signals from Satellital Modem Message-ID: Date: Mon, 10 Jul 2006 23:09:16 GMT wrote in message news:1152298653.803900.283720@s13g2000cwa.googlegroups.com... > I'm to install a satellital modem (Globalstar GSP-1620) in a place > where there's no full direct sky visibility due to some metallic > obstacules. > To overcome this problem I'm thinking of placing a reradiating antenna > or RF repeater over the top of the highest obstacule, facing the real > GSP1620 antenna down on the ground. > > The GSP1620 has two RF frequencies, one for TX (1610-1625 Mhz) and > another for RX (2484-2499 Mhz). Does anyone have any ideas on how to > build up such reradiating antenna and/or RF repeater ? Is there any > commercial product similar to this ? > > Thanks a lot. > Pablo Hi Pablo I am curious about your globalstar instalation. What kind of antenna will you use at the location that "sees" the satellites? And, why is it *not* OK to use coax cable from the remote antenna to the telephone in the shadows? I am currently trying to build an antenna for Chris W. for his Globalstar satelite phone. Jerry Article: 226259 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 16:20:57 -0700 Message-ID: References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> On Mon, 10 Jul 2006 17:57:42 -0400, John Popelish wrote: >> Hi John, >> >> In fact a larger disk will actually raise the launch angle - hardly a >> satisfactory mirror analogy. >> >> >>>the "mirror" produces (half of the) photons that the >>>full dipole would have produced. >> >> >> Photons? This is CecilBabble. Mirrors as "productive" sources of >> photons demonstrates the failure of analogies. > >Do you deny the photonic nature of radio waves? Hi John, This last question is standard CecilBaiting at which he is a master. I've made a career in photonics, so you will have to go some distance to start offering a case that comes remotely close to their cross application. Barring that, why introduce concepts that don't advance the topic? The following is hardly any clearer by clinging to poor metaphors: >I just realized that the sentence you quoted s easily misinterpreted. > When I said "the "mirror" produces (half of the) photons that the >full dipole would have produced." I meant that half as many photons >are produced, compared to the full dipole antenna that produces the >same fields above the center line. I didn't mean that the mirror >produces half of the total photons that are radiated. 73's Richard Clark, KB7QHC Article: 226260 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 19:40:59 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> Message-ID: Richard Clark wrote: > On Mon, 10 Jul 2006 17:57:42 -0400, John Popelish > wrote: >>Do you deny the photonic nature of radio waves? > > > Hi John, > > This last question is standard CecilBaiting at which he is a master. > > I've made a career in photonics, so you will have to go some distance > to start offering a case that comes remotely close to their cross > application. Barring that, why introduce concepts that don't advance > the topic? The following is hardly any clearer by clinging to poor > metaphors: I guess the perceived quality of any given metaphor depends on your mental model of the rest of the universe. Antennas and photons work for me. If they don't work for you, I have no problem with that. Remember, it is Cecil, not me, who demands agreement or eternal verbal torture. Article: 226261 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 16:52:09 -0700 Message-ID: References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> On Mon, 10 Jul 2006 19:40:59 -0400, John Popelish wrote: >I guess the perceived quality of any given metaphor depends on your >mental model of the rest of the universe. Antennas and photons work >for me. If they don't work for you, I have no problem with that. hi John, It would seem that they "don't" work for you. I have no problem shifting to a photonic dialog, but you have yet to emerge from a rather muddy start. >Remember, it is Cecil, not me, who demands agreement or eternal verbal >torture. I can torture with the best of them too. Choose your metaphors well to avoid the embarrassment of Abu Graib. 73's Richard Clark, KB7QHC Article: 226262 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Quarterwave vertical with radials Date: Mon, 10 Jul 2006 17:04:54 -0700 Message-ID: References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> On Mon, 10 Jul 2006 17:57:42 -0400, John Popelish wrote: > I meant that half as many photons >are produced, compared to the full dipole antenna that produces the >same fields above the center line. Hi John, So, proceeding along your avowed lines of Photons, one of several questions: Presuming 100W radiated, how many photons would that be so that we can talk about them by halves. Yes, that is perhaps unfair, however it demonstrates how easily the discussion can tumble for lack of quantifiables such as that original offering of 100W. Should we discuss how infinitesimal the energy is in a 40M photon? (Easily accounts for why so many are needed for that same 100W.) No, I suppose not. Want to get into the problems of diffraction with object lenses that measure less than a wavelength of the photon? Hard to escape, and makes a mess of describing mirrors too, especially when they are skeletal approximations as well. I can offer more thread-busters when it comes to photonics, but that is a slam dunk. Get us rolling on one ace proposition, and I will get back to you in a couple of hours. 73's Richard Clark, KB7QHC Article: 226263 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Quarterwave vertical with radials Date: 10 Jul 2006 17:28:39 -0700 Message-ID: <1152577718.983360.125300@75g2000cwc.googlegroups.com> References: Roy Lewallen wrote: > John - KD5YI wrote: > > > > Actually, on elevated antennas (as in the usual VHF setup), just two > > quarter-wave radials 180 degrees apart is almost indistinguishable from > > 4 or more radials. EZNEC shows very little change in terminal impedance > > and pattern by removing two radials from a 4 radial ground plane. > > > > I once used copper tape on a window to make a ground plane vertical like > > that for 70cm. It worked very well. > > George Brown, the inventor of the ground plane antenna, found that only > two radials were necessary. But when his company went to sell it, the > marketing department decided that no one would buy a two-radial ground > plane antenna in the belief that it would be omnidirectional. So they > added two more to make it "look" more omnidirectional. The four-radial > ground plane persists to this day. The real reason to use 4 radials or more is decoupling the feedline shield. Decoupling is very bad with two radials unless you get lucky with feedline and/or mast length or use a decoupling aid like a common mode choke. On a commercial 47 Mhz GP I designed that had 4 radials, the radials had to be isolated from the mounting and a ferrite decoupling sleeve placed over the coax. I can't imagine how bad that problem would be with only two radials. 73 Tom Article: 226264 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Quarterwave vertical with radials Date: 10 Jul 2006 17:33:43 -0700 Message-ID: <1152578023.253600.314910@m73g2000cwd.googlegroups.com> References: Cecil Moore wrote: > Tom Donaly wrote: > > If you can bring yourself to think in terms of > > current directions and far field superposition of waves, this > > behavior shouldn't be that hard to understand. > > It's pretty easy to understand. Any two radials, > 180 degrees apart and high enough, should theoretically > cancel each other's radiation in the far field. Not true. There is always an angle and direction where the fields do not fully cancel. The problem is the spatial distance is different unless exactly broadside to the pair. Even 4 radials has this problem, but the more radials the less of an issue it is. 73 Tom Article: 226265 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Quarterwave vertical with radials Date: 10 Jul 2006 17:37:22 -0700 Message-ID: <1152578242.141283.306400@p79g2000cwp.googlegroups.com> References: Reg Edwards wrote: > George Brown was over precautious. Only one vertical radial is > needed. There is no loss in efficiency. The radiation pattern remains > sensibly the same. > ---- > Reg. All you have to do is figure out how to decouple the feedline for less cost than the cost of three additional radials and a tiny easy to build choke. Getting the feedline off a four radial GP is bad enough. Article: 226266 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Voltage feeding a VHF yagi Date: 10 Jul 2006 17:44:31 -0700 Message-ID: <1152578671.148819.275420@b28g2000cwb.googlegroups.com> References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> Cecil Moore wrote: > It certainly isn't that simple in a distributed network. > The currents into the end of a half-wave section are certainly > unbalanced at X and Y but the current amplitudes are pretty low. > 5 watts into 5000 ohms is only about 30 mA. 1/4WL back at the > shorted matching section at ++, Not that it ever does any good to try to get you to think about what you are saying, but that is nonsense Cecil. The short doesn't affect CM currents. The 1/4 wl line can act as current step up if the far end is grounded. Also, reach back in your rear and pull out another impedance number. The impedance value you grabbed from there is for a very thin wire compared to length, like an end-fed HF antenna. Tubing is alot lower on the end Cecil OM. Before going off on another Cecil-knows-best event and destroying a thread to make it all about you, run the model. Six meters, yagi, tubing. Not 40 meters and #16 wire. Article: 226267 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 20:52:38 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> Message-ID: Richard Clark wrote: > On Mon, 10 Jul 2006 17:57:42 -0400, John Popelish > wrote: > > >>I meant that half as many photons >>are produced, compared to the full dipole antenna that produces the >>same fields above the center line. > > > Hi John, > > So, proceeding along your avowed lines of Photons, one of several > questions: > Presuming 100W radiated, how many photons would that be so that we > can talk about them by halves. Well, you couldn't be radiating 100 watts in both cases if the field strength is the same above the center line, but half the field is missing in one of the cases. But regardless of the radiating structure, if 100 watts at 40 M is being radiated, you are launching about 2*10^28 photons per second. > Yes, that is perhaps unfair, however it demonstrates how easily the > discussion can tumble for lack of quantifiables such as that original > offering of 100W. Hence the stipulation that the field strength above the centerline being constant, rather than the radiated power. I missed that we were only talking about a case of radiating 100 watts. > Should we discuss how infinitesimal the energy is in a 40M photon? > (Easily accounts for why so many are needed for that same 100W.) Not much to discuss. I don't do such calculations often, but I get about 5*10^-27 joule per photon. What do you calculate their energy to be? > No, I suppose not. Do you have some point? > Want to get into the problems of diffraction with object lenses that > measure less than a wavelength of the photon? Sure. That will take us back to how an elevated radial system gives a different vertical pattern than an actual ground plane or a lossy ground does. You go first. > Hard to escape, and makes a mess of describing mirrors too, especially > when they are skeletal approximations as well. You have to start understanding mirrors, somewhere. Perhaps you prefer a different starting point. There are several. > I can offer more thread-busters when it comes to photonics, but that > is a slam dunk. Get us rolling on one ace proposition, and I will get > back to you in a couple of hours. I have no idea what you are saying with these two sentences. Article: 226268 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 21:02:21 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1152577718.983360.125300@75g2000cwc.googlegroups.com> Message-ID: w8ji@akorn.net wrote: > Roy Lewallen wrote: > >>John - KD5YI wrote: >> >>>Actually, on elevated antennas (as in the usual VHF setup), just two >>>quarter-wave radials 180 degrees apart is almost indistinguishable from >>>4 or more radials. EZNEC shows very little change in terminal impedance >>>and pattern by removing two radials from a 4 radial ground plane. >>> >>>I once used copper tape on a window to make a ground plane vertical like >>>that for 70cm. It worked very well. >> >>George Brown, the inventor of the ground plane antenna, found that only >>two radials were necessary. But when his company went to sell it, the >>marketing department decided that no one would buy a two-radial ground >>plane antenna in the belief that it would be omnidirectional. So they >>added two more to make it "look" more omnidirectional. The four-radial >>ground plane persists to this day. > > > The real reason to use 4 radials or more is decoupling the feedline > shield. > > Decoupling is very bad with two radials unless you get lucky with > feedline and/or mast length or use a decoupling aid like a common mode > choke. Awe, you ruined the suspense. > On a commercial 47 Mhz GP I designed that had 4 radials, the radials > had to be isolated from the mounting and a ferrite decoupling sleeve > placed over the coax. I can't imagine how bad that problem would be > with only two radials. Article: 226269 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 21:27:14 -0400 From: VOA SWLer Subject: Sept 9+10 - ARRL MDC Section Convention Message-ID: Click on: for info. Article: 226270 of rec.radio.amateur.antenna From: pierred1@sympatico.ca Subject: Radial versus reflection Date: 10 Jul 2006 18:33:48 -0700 Message-ID: <1152581628.528396.6170@m73g2000cwd.googlegroups.com> Hi to all This is a related question to an earlier subject. The ''help'' file of EZNEC says that ''The ground reflections which cause the low-angle pattern reflections take place farther from the antenna than most common radial ground systems extend, so ground radial systems have little or no effect on the ground reflection phenomenon.'' My question: Supposing that there are radiations coming from the antenna and going downwards (maybe at very steep angle), those rays could be reflected on the radial system and could add to the pattern, for any radial length... The above sentence don't seems to validate such phenomenon.. So any further explanation would be welcome. 73 de VE2PID Article: 226271 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> Message-ID: Date: Tue, 11 Jul 2006 01:59:51 GMT Richard Clark wrote: > On Mon, 10 Jul 2006 17:57:42 -0400, John Popelish > wrote: > > >>I meant that half as many photons >>are produced, compared to the full dipole antenna that produces the >>same fields above the center line. > > > Hi John, > > So, proceeding along your avowed lines of Photons, one of several > questions: > Presuming 100W radiated, how many photons would that be so that we > can talk about them by halves. > > Yes, that is perhaps unfair, however it demonstrates how easily the > discussion can tumble for lack of quantifiables such as that original > offering of 100W. > > Should we discuss how infinitesimal the energy is in a 40M photon? > (Easily accounts for why so many are needed for that same 100W.) > > No, I suppose not. > > Want to get into the problems of diffraction with object lenses that > measure less than a wavelength of the photon? > > Hard to escape, and makes a mess of describing mirrors too, especially > when they are skeletal approximations as well. > > I can offer more thread-busters when it comes to photonics, but that > is a slam dunk. Get us rolling on one ace proposition, and I will get > back to you in a couple of hours. > > 73's > Richard Clark, KB7QHC How many photons does it take to make a Watt? 73, Tom Donaly, KA6RUH Article: 226272 of rec.radio.amateur.antenna Date: Mon, 10 Jul 2006 22:12:57 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> Message-ID: Tom Donaly wrote: > How many photons does it take to make a Watt? 1/(Hz*6.63*10^-34). The lower the frequency the less energy per photon. Article: 226273 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 02:17:55 GMT w8ji@akorn.net wrote: > Cecil Moore wrote: > >>Tom Donaly wrote: >> >>>If you can bring yourself to think in terms of >>>current directions and far field superposition of waves, this >>>behavior shouldn't be that hard to understand. >> >>It's pretty easy to understand. Any two radials, >>180 degrees apart and high enough, should theoretically >>cancel each other's radiation in the far field. > > > Not true. > > There is always an angle and direction where the fields do not fully > cancel. The problem is the spatial distance is different unless exactly > broadside to the pair. > > Even 4 radials has this problem, but the more radials the less of an > issue it is. > > 73 Tom > How much not true? I expect you're right, but you could make the same argument that a two wire transmission line radiates because the wires don't occupy exactly the same physical space. Reg made the same point, but didn't provide any numbers, so, according to his own philosophy he doesn't understand the problem. 73, Tom Donaly, KA6RUH Article: 226274 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Radial versus reflection Date: Mon, 10 Jul 2006 19:23:03 -0700 Message-ID: <12b62s9dgqj28af@corp.supernews.com> References: <1152581628.528396.6170@m73g2000cwd.googlegroups.com> pierred1@sympatico.ca wrote: > Hi to all > > This is a related question to an earlier subject. > > The ''help'' file of EZNEC says that ''The ground reflections which > cause the low-angle pattern reflections take place farther from the > antenna than most common radial ground systems extend, so ground radial > systems have little or no effect on the ground reflection phenomenon.'' > > My question: Supposing that there are radiations coming from the > antenna and going downwards (maybe at very steep angle), those rays > could be reflected on the radial system and could add to the pattern, > for any radial length... > > The above sentence don't seems to validate such phenomenon.. So any > further explanation would be welcome. Note the qualification "low-angle" in the sentence you quoted. radiations going downward at a steep angle will be reflected off the ground plane. I tried to explain this in my previous postings, but apparently wasn't successful. Roy Lewallen, W7EL Article: 226275 of rec.radio.amateur.antenna From: pierred1@sympatico.ca Subject: Re: Radial versus reflection Date: 10 Jul 2006 19:40:55 -0700 Message-ID: <1152585655.191122.52130@m73g2000cwd.googlegroups.com> References: <1152581628.528396.6170@m73g2000cwd.googlegroups.com> Roy Lewallen wrote: > pierred1@sympatico.ca wrote: > Note the qualification "low-angle" in the sentence you quoted. > radiations going downward at a steep angle will be reflected off the > ground plane. I tried to explain this in my previous postings, but > apparently wasn't successful. > > Roy Lewallen, W7EL Roy, about the example from another subject, you (correctly) illustrated that any radiation for an angle of 26 degrees or less will be beyond the radial field But what about an angle of say 35 deg below horizon? That ray would bounce on the radial field, is'nt it?? That 35 deg is an example of a ''steep angle'' Article: 226276 of rec.radio.amateur.antenna From: Marklinbuyer@gmail.com Subject: New Swiss antenna system... Date: 10 Jul 2006 20:36:13 -0700 Message-ID: <1152588973.511463.222930@p79g2000cwp.googlegroups.com> Here is a very interesting article from SwissInfo. A zeppelin will replace all of the terrestrial mobile phone antennas in Switzerland - if a Swiss inventor has his way. Should Kamal Alavi's project for the high-tech airship take wing, the worlds of mobile telephony and data transmission would be turned on their heads. Not only would the technology, called High Altitude Platform Systems (Haps), make the current 1,000 earth-bound antennas redundant, it would drastically reduce radiation. A Swiss of Iranian extraction, Alavi is a former aerospace engineer turned entrepreneur who heads his own firm, Stratxx. Together with a team of 50 scientists, he is preparing a 2007 test run of the airship, which he has named the "X station". Thanks to a GPS steering system developed by the Swiss Federal Institute of Technology, the 60-meter long helium-filled balloon will remain stationary at 21 kilometres above the earth. A small-unmanned aircraft outfitted with a mobile phone antenna and other devices for transmitting digital data will be attached to the zeppelin. The X station has been equipped with giant propellers to help counter the almost constant buffeting from the wind. Solar panels will supply the energy to propel the airplane and antenna. Underneath will be a platform containing technical equipment, conceived by Ruag, the large Swiss aerospace concern. Radiation "Transmitting on earth causes lots of radiation, because you have to penetrate countless buildings," Alavi says, arguing that phone connections are more reliable when transmitted from above because the signals are unobstructed by manmade or natural objects. And "spot beam" antennas developed at Lausanne will allow radiation to be adjusted according to usage, regions with little activity receiving relatively less. But Switzerland's largest mobile telephone operator, Swisscom believes not all of the technological hurdles have been overcome. "This project cannot replace the present mobile telephone system," spokesman Sepp Huber told swissinfo. The X station would not be limited to forwarding mobile telephone signals, but would also be capable of handling the radio, television and internet needs of entire nations. Alavi believes that his project is also economical. He estimates that a Haps airship will cost no more than SFr40 million ($32 million). In comparison, a single mobile phone antenna costs about SFr300,000 while a communications satellite starts at SFr600 million. Alavi says the X stations are conceived to be low maintenance. In the event of a defect, the aircraft will be decoupled from the airship and returned to earth, much like a mini-space shuttle. The project is now in a key phase. Solar cells are being tested at an altitude of 30 kilometres, and final preparations are underway for the launch of the first airship into the stratosphere. The entire system should be ready for testing a year from now. The potential is enormous if Stratxx manages to be the first to fly with this new technology. About 20 Haps would be required to cover Europe alone while Africa would need twice as many. swissinfo, Etienne Strebel So, has anyone or group tried to get a couple ham antennas on this thing??? Bill http://MarklinBuyer.com I buy Marklin model trains Article: 226277 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> Message-ID: Date: Tue, 11 Jul 2006 03:53:55 GMT Reg Edwards wrote: > A pair of radials behave as a continuous dipole fed at its center via > a single wire. And it radiates. If the radials are horizontal and radiating, why is there virtually no horizontally polarized radiation? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226278 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Induced signal? References: Message-ID: Date: Tue, 11 Jul 2006 03:56:07 GMT Dave wrote: > remember, 1/4 wave long (more or less) makes the open at > one end look like a short at the other end. There is an open at both ends. Does that make it look like a short at both ends? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226279 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> Message-ID: Date: Tue, 11 Jul 2006 03:58:22 GMT John Popelish wrote: > Remember, it is Cecil, not me, who demands agreement or eternal verbal > torture. I don't demand agreement, John, just resolution. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226280 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 04:09:53 GMT w8ji@akorn.net wrote: > Cecil Moore wrote: >> It's pretty easy to understand. Any two radials, >> 180 degrees apart and high enough, should theoretically >> cancel each other's radiation in the far field. > > Not true. > There is always an angle and direction where the fields do not fully > cancel. Funny, I don't see "fully cancel" anywhere in my posting. I probably should have said "tend to cancel". A free space vertical with horizontal radials in EZNEC has horizontal radiation more than 40 dB down from the vertical radiation. That's a high degree of cancellation. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226281 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Voltage feeding a VHF yagi References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> <6cjvn3-s7p.ln1@p400bob.personal.cox.net> <1152218809.770077.3670@s26g2000cwa.googlegroups.com> <1152222378.456155.303810@j8g2000cwa.googlegroups.com> <1152233762.848358.152070@s13g2000cwa.googlegroups.com> <1152578671.148819.275420@b28g2000cwb.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 04:30:20 GMT w8ji@akorn.net wrote: > The short doesn't affect CM currents. I1 +--<---A------------X----------------------------- | +--<---B------------Y I2 I1 and I2 are common-mode. What do you suppose will happen at the short? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226282 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 04:36:24 GMT Tom Donaly wrote: > w8ji@akorn.net wrote: > >> Cecil Moore wrote: >>> It's pretty easy to understand. Any two radials, >>> 180 degrees apart and high enough, should theoretically >>> cancel each other's radiation in the far field. >> >> Not true. > > How much not true? -45 DB, i.e. negligibly not true. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 226283 of rec.radio.amateur.antenna From: John - KD5YI Subject: Re: Induced signal? References: Message-ID: Date: Tue, 11 Jul 2006 04:45:08 GMT Cecil Moore wrote: > Dave wrote: > >> remember, 1/4 wave long (more or less) makes the open at one end look >> like a short at the other end. > > > There is an open at both ends. Does that make it look like > a short at both ends? If it looked like a short at both ends, it would look like an open at both ends. Article: 226284 of rec.radio.amateur.antenna From: Subject: Need help on QRM rejection ( WITHOUT A BEAM !!) Date: Tue, 11 Jul 2006 00:28:43 -0500 Message-ID: I am working with MARS on 75m. I am seeing some horrific QRM esp today but generally every day and definitely need some help on rejecting the noise. I have a DX-CC inverted at about 35' on a 40'+ Army fiberglass mast attached to one leg of my Rohn Tower. Waiting for a tower party, there is only about 18' of it sticking out of the 4x4' concrete tub I poured for it. One end of this dipole is about 20' off the ground to the NE of my mast and the SW end of it is about 12' above the roof of the house. MAYBE.. the 1900H Net tonight was almost impossible with a noise factor of about 7 or 8 and very few of the people on the net were pushing signals above that. The morning NET was much better but by 0830, it was also beyond my ability to make out who was talking from anywhere. and that included the NCS which was about 30 mi North of me. It isn't just 75m... I find this to be a problem on virtually evey band I try including VHF/UHF I have an Icom 736 with its built in tuner and ANY noise rejection is just simply beyond its abilities or... perhaps I do not know how to get it to reject. The notch filter on this is really rudimentary compared to today's txcvrs But hell, who can afford a decent radio at today's prices?. I suppose I ought to set up my 728 and see if it is any better but it does not have a tuner or a power supply. Still, I have those and I guess it might be worth playing with it for several hours just to see if the problem is in my 736. However, the evening NCS was also talking about the high QRM but others were able to work thru it. I am thinking that I need to get a 80m Carolina Windom and set it up flat across the back yard at about 50' by using trees in the neighbors yards. any other ideas on solving this problem?? thanks 73s chas K5DAM ... Article: 226285 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Induced signal? Date: 10 Jul 2006 22:47:25 -0700 Message-ID: <1152596844.979077.148290@m79g2000cwm.googlegroups.com> References: Built a skeleton piece of giant coax in EZNEC, been playing with it as a monopole over MININEC ground. I'm not going to claim much since it's probably wildly inapplicable, but I will claim that the answer to this question ain't trivial and depends on the details of the ends. I find a current in the center conductor, It's very much bigger when the center conductor is slightly extended past the ends of the "shield" than when it's slightly inside. The shield is eight wires arranged in a regular octogon with the tops and bottoms tied together. It shows more or less normal fat monopole behavior when used alone. (33 foot element resonant around 6.4 MHz) A fatter wire used for the center conductor has greater current than a thinner one. A very thin wire exhibits almost no current. The peak current in the center conductor is about 3% of what's flowing in the shield for a 1 foot "diameter" (the circumscribed circle around the octagon) shield and a 6 inch diameter inner conductor. The current is very low at either end of the center conductor and peaks about 2/3 >from the top. This dumb model is full of holes of many kinds, I'm sure, but it does seem to show nontrivial effects of changing things a little bit near the ends of the coax (slight extension of center conductor outside of/retraction of center conductor into the shield) Dan Article: 226286 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Induced signal? Date: 11 Jul 2006 01:47:46 -0700 Message-ID: <1152607665.959599.175290@s13g2000cwa.googlegroups.com> References: Cecil Moore wrote: > Here's a question overflowing from eHam.net and it's > not a trick question. > > Assume that the radiating portion of a 40m vertical > is made out of 33 feet of RG-213 and the braid is > the radiator. The center conductor of the coax is > left floating at both ends. How much RF voltage > and/or current will be induced in that center wire > when using the outside braid as the radiator for > 100 watt operation? How much of an EM field can > exist inside the coax braid? I know this will shock regular group users, but he has taken things WAY out of context in the question above! The actual problem is this: A fellow placed a relay at the top of a half square antenna to change directions by switching from one flat top and drop wire to another. This is a VOLTAGE fed antenna at the ground. The vertical wires at the antenna ends have to be an electrical 1/4 wl long on the OUTSIDE for the system to work properly. Cecil suggested he simply run the relay wires up inside a "shield" to the relay, and the shield would prevent the relay control wires from affecting the very high feed impedance at the base. The shield could be used as the actual vertical antenna lead. Now I know to many people the problem is obvious. The problem is the IMPEDANCE of the open stub formed at the bottom of the vertical sleeve by the inner wire that has to go to a control system of some type and the outer sleeve. That impedance has to be many ten's of kilo ohms so the shunting impedance is high compared to the impedance of the sleeve. Full RF voltage of the feedpoint is also across the gap where the center wires leave the shield. In order for the shield to have some meaningful effect on the system other than simply running the wires down in parallel with the fed wire, the impedance between the inner wire and shield must be VERY high at the bottom. It can of course be a SHORT at the top, since the relay just sits up there in the air with only the contacts making a connection, so the top is easy to handle with some bypass caps. What Cecil totally misses is he formed what is in effect the electrical equivalent of a sleeve balun. The velocity factor of the transmission line forming this stub has to be the SAME as the outside of the sleeve so the INSIDE is 1/4 wl long electrical, and the the loss has to be very low. Otherwise the common mode impedance of the relay wires exiting the shield will not be several times higher than the antenna feed impedance, which is several k-ohms. I've seen antenna manufacturers make the same mistake Cecil just made, and assume that running a cable down the center of a "hot" mast that is part of an antenna means the wires have zero current and zero effect since they are inside the shield, but anyone with any understanding of how the system works would catch the flaws in this idea right away. The flaw is the differential IMPEDANCE between the shield and the shell forming an antenna has to be several times the common mode impedance of the shell or the system won't be worth a flip. Without that high impedance, the inner wire might as well just run down the outside of the sleeve and a couple good HV high impedance RF chokes be used to supply relay control voltage. As a matter of fact at AM BC stations, when using two way or RPU antennas on the hot base insulated towers, I never bothered with running the cables INSIDE the tower. I went up 1/4 wl above the base, and bonded the cables to the tower. I spaced the cables a foot or so off the tower face on large insulators, so it formed an open 1/4 wl very low loss stub. This made the differential mode impedance of the open stub end at the ground very high, and allowed the cables to be brought away from the hot tower base without interacting a large amount with the tower base impedance. This is a very simple common system that is often used in antennas (often in BC systems) , and once in a while used incorrectly by Hams and Ham antenna manufacturers (like Gap and MFJ and a few manufacturers of Ham log periodics). Cecil will catch on with help I'm sure, I just don't have time to walk him through the problem step by step. 73 Tom Article: 226287 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Quarterwave vertical with radials Date: 11 Jul 2006 02:22:15 -0700 Message-ID: <1152609735.071204.264590@m79g2000cwm.googlegroups.com> References: Cecil Moore wrote: > Funny, I don't see "fully cancel" anywhere in my posting. > I probably should have said "tend to cancel". > > A free space vertical with horizontal radials in EZNEC > has horizontal radiation more than 40 dB down from the > vertical radiation. That's a high degree of cancellation. The issue is the horizontal opposing radials only have that degree of cancellation for perfectly horizontal directions. You will be able to see your statement isn't true if you place the antenna in freespace and look at pattern distortion at various elevation angles. For example, the 2-d plot is skewed 2.11 dB from being circular at - 45 and +45 degrees elevation. The skewing gets worse at larger angles from the plane of the radials. If the radials were REALLY radiating -40dB in all directions as you wrongly assume, there would NOT be significant FS change in the azimuth pattern at various elevations. You looked at horizontal radiation, but the horizontal radials peak radiation is vertically polarized and nearly off the radial's ends. (Just like in a dipole pattern.) The radials do indeed radiate enough to change the pattern a significant amount (but not at zero degrees), but the largest problem is decoupling the feedline shield. The fewer radials are used, the bigger the problem becomes. There are VERY good reasons everyone settled on four radials, and it isn't the old wive's tale about making the antenna look good. Four radials is a reasonable compromise between excessive common mode problems and tolerable common mode feedline current problems, pattern, and cost. Don't feel bad though Cecil. Many people miss this point, even card carrying Mensa members. 73 Tom Article: 226288 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Voltage feeding a VHF yagi Date: 11 Jul 2006 02:23:43 -0700 Message-ID: <1152609823.761832.13220@p79g2000cwp.googlegroups.com> References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> Cecil Moore wrote: > w8ji@akorn.net wrote: > > The short doesn't affect CM currents. > > I1 > +--<---A------------X----------------------------- > | > +--<---B------------Y > I2 > > I1 and I2 are common-mode. What do you suppose will > happen at the short? > -- > 73, Cecil http://www.qsl.net/w5dxp I know what happens. The problem is what YOU are supposing happens. Article: 226289 of rec.radio.amateur.antenna From: Alan WA4SCA Subject: Re: New Swiss antenna system... Message-ID: <5jr6b2hhgh4ibhqb6v24l3iip806hf5v2g@4ax.com> References: <1152588973.511463.222930@p79g2000cwp.googlegroups.com> Date: Tue, 11 Jul 2006 09:26:35 GMT There are a couple of countries in Central and South America which do essentially the same thing with a central mountain. However, mountains are seldom grounded due to extreme weather conditions. -- Alan WA4SCA Article: 226290 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 20:32:30 +1000 From: Zen Subject: Antennal Model? opinions? Message-ID: <44b37e3f$1_1@news.iprimus.com.au> Can anyone who uses Antenna Model software from Terri Software give a pros and cons summary. I am considering buying the software. Zenki Article: 226291 of rec.radio.amateur.antenna From: "Reg Edwards" References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> Subject: Re: Quarterwave vertical with radials Date: Tue, 11 Jul 2006 12:46:38 +0100 Message-ID: <-KSdnXVeB9D7DS7ZRVnyrQ@bt.com> > Reg Edwards wrote: > > A pair of radials behave as a continuous dipole fed at its center via > > a single wire. And it radiates. > > If the radials are horizontal and radiating, why is > there virtually no horizontally polarized radiation? > -- > 73, Cecil ====================================== Cec, Your use of the word "virtually" indicates a weakness in your ideas on the subject. The radiation, as small as it may be, is vertically polarised. ---- Reg. From k6mhek6mhecom> Newsgroups: rec.radio.amateur.antenna Subject: Re: Antennal Model? opinions? Date: Tue, 11 Jul 2006 05:08:23 -0700 Message-ID: <9257b2h6joe77lh046i68hoi6oscums0mc@4ax.com> References: <44b37e3f$1_1@news.iprimus.com.au> X-Newsreader: Forte Agent 1.93/32.576 English (American) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 28 NNTP-Posting-Host: 68.64.59.124 X-Trace: sv3-B33MmJVU7Bv/Vn0Cnb8zhXaOW+4dptYCqSm4uwuJYAkqCVtlFuVgsyaOk7Erxv68Nq2ZRlRg8iez6bw!Q7kik09S8/h8qgx2BS/8EPc7mT8pf4ovBFOgFtytKX2LJJ5cjQ2Phs4uqUIUk/j0EZxqJuRDbEJl!U6TDPnND2do7s2mWPKud X-Complaints-To: abuse@adelphia.net X-DMCA-Complaints-To: copyright@adelphia.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.32 Path: news.unc.edu!elk.ncren.net!arclight.uoregon.edu!wns14feed!worldnet.att.net!216.196.98.141!border2.nntp.dca.giganews.com!nntp.giganews.com!local01.nntp.dca.giganews.com!nntp.adelphia.com!news.adelphia.com.POSTED!not-for-mail Xref: news0.isis.unc.edu rec.radio.amateur.antenna:226292 On Tue, 11 Jul 2006 20:32:30 +1000, Zen wrote: >Can anyone who uses Antenna Model software from Terri Software give a >pros and cons summary. I am considering buying the software. > I have Antenna Model along with several implementations of NEC (both NEC2 and NEC4). Which modeling program I used depends upon the antenna and the type of installation I wish to model as each has its strong points. Antenna Model uses the MININEC engine, however, it has been highly modified which removes many of MININEC's short comings. It is possible to model some antenna configurations that NEC has difficulty (and visa versa), for example, a Log periodic with a physical transmission line. Like most NEC implementations, Antenna Model allows the use the Sommerfeld ground model - something that other versions of MININEC do not, however, it will not model buried radials as can be done NEC4. Antenna Model, like EZNEC, gives excellent customer support. Updates are free and good for life. I find having both Antenna Model and NEC based programs gives me the option of choosing best program for the situation. 73, Danny, K6MHE From k6mhek6mhecom> Newsgroups: rec.radio.amateur.antenna Subject: Re: Quarterwave vertical with radials Date: Tue, 11 Jul 2006 05:39:05 -0700 Message-ID: References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> <1152609735.071204.264590@m79g2000cwm.googlegroups.com> X-Newsreader: Forte Agent 1.93/32.576 English (American) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 25 NNTP-Posting-Host: 68.64.59.124 X-Trace: sv3-LesU+xbrmGwwJRpwndqaykXDEnY4jp4txFhx0DOdYqLiLUgEseR9JmHfoffVHQLUopo/jWmBZvXcbhn!lmM/kmeBdxJKbFkEGhRRdJamzvA3n4TfjO7Dp2QTeC79pwCgUfV6rYQFe+l5wEgkWRF9TX5NFUxR!RPpc+fLy+Uq+rHw1frEH X-Complaints-To: abuse@adelphia.net X-DMCA-Complaints-To: copyright@adelphia.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.32 Path: news.unc.edu!elk.ncren.net!arclight.uoregon.edu!wns14feed!worldnet.att.net!216.196.98.141!border2.nntp.dca.giganews.com!nntp.giganews.com!local01.nntp.dca.giganews.com!nntp.adelphia.com!news.adelphia.com.POSTED!not-for-mail Xref: news0.isis.unc.edu rec.radio.amateur.antenna:226293 On 11 Jul 2006 02:22:15 -0700, w8ji@akorn.net wrote: >There are VERY good reasons everyone settled on four radials, and it >isn't the old wive's tale about making the antenna look good. Four >radials is a reasonable compromise between excessive common mode >problems and tolerable common mode feedline current problems, pattern, >and cost. I don't think that is a "wive's tale". >From George Brown's (one of the co-inventors of the ground-plane) book "and part of which I was" the following quote about the ground plane antenna: ".... In our initial experiments we found that only two horizontal rods (ground rods) functions just as well as four. Many people from the Broadcast Sales organization came by to view our test and they always expressed doubts as to the ability to radiate uniformity when only two ground rods were used. To quiet them, we used four ground rods for a while, thus stilling the criticism. When the antenna became really popular, we did not dare confess to our ruse." Danny, K6MHE Article: 226294 of rec.radio.amateur.antenna From: "Reg Edwards" References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> <1152609735.071204.264590@m79g2000cwm.googlegroups.com> Subject: Re: Quarterwave vertical with radials Date: Tue, 11 Jul 2006 14:35:34 +0100 Message-ID: What's the matter with 3, equi-spaced radials? Be economical. Save a radial! It looks better too. And there are no arguments about directionality. ---- Reg. Article: 226295 of rec.radio.amateur.antenna From: "neil .scotland uk." References: Subject: Re: Need help on QRM rejection ( WITHOUT A BEAM !!) Message-ID: Date: Tue, 11 Jul 2006 13:57:28 GMT hi ;;check if anyone at home or nearby using -equpment with "SWITCHMODE"POWER SUPPLY.--just a thought-- GM0LTQ wrote in message news:lcd6b2h22kk1tsk429oc3h7i9rpqup49ob@4ax.com... >I am working with MARS on 75m. I am seeing some horrific QRM esp today >but > generally every day and definitely need some help on rejecting the noise. > > I have a DX-CC inverted at about 35' on a 40'+ Army fiberglass mast > attached to one leg of my Rohn Tower. Waiting for a tower party, there is > only about 18' of it sticking out of the 4x4' concrete tub I poured for > it. > One end of this dipole is about 20' off the ground to the NE of my mast > and > the SW end of it is about 12' above the roof of the house. MAYBE.. > > the 1900H Net tonight was almost impossible with a noise factor of about 7 > or > 8 and very few of the people on the net were pushing signals above that. > The > morning NET was much better but by 0830, it was also beyond my ability to > make > out who was talking from anywhere. and that included the NCS which was > about > 30 mi North of me. > > It isn't just 75m... I find this to be a problem on virtually evey band > I > try including VHF/UHF > > I have an Icom 736 with its built in tuner and ANY noise rejection is > just > simply beyond its abilities or... perhaps I do not know how to get it to > reject. > The notch filter on this is really rudimentary compared to today's txcvrs > But > hell, who can afford a decent radio at today's prices?. > > I suppose I ought to set up my 728 and see if it is any better but it does > not > have a tuner or a power supply. Still, I have those and I guess it might > be > worth playing with it for several hours just to see if the problem is in > my > 736. However, the evening NCS was also talking about the high QRM but > others > were able to work thru it. > > I am thinking that I need to get a 80m Carolina Windom and set it up flat > across the back yard at about 50' by using trees in the neighbors yards. > > any other ideas on solving this problem?? > > thanks > 73s chas > K5DAM > > > > ... Article: 226296 of rec.radio.amateur.antenna From: "JC" Subject: Antenna optimization Date: Tue, 11 Jul 2006 16:03:46 +0200 Message-ID: <44b3afc1$0$990$ba4acef3@news.orange.fr> Is there a software which can design an antenna (like EZNEC or similar ) then allows to automatically optimize its dimensions according to given requirements: max gain, F/B, min swr... and accepted dimensional parameters changes: boom length, spacing.... JC Article: 226297 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Induced signal? References: <1152607665.959599.175290@s13g2000cwa.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 14:06:32 GMT w8ji@akorn.net wrote: > The actual problem is this: Seems logical to discuss the simpler coax example before introducing an example that is more complicated and harder to understand. > A fellow placed a relay at the top of a half square antenna to change > directions by switching from one flat top and drop wire to another. > This is a VOLTAGE fed antenna at the ground. The vertical wires at the > antenna ends have to be an electrical 1/4 wl long on the OUTSIDE for > the system to work properly. > > Cecil suggested he simply run the relay wires up inside a "shield" to > the relay, and the shield would prevent the relay control wires from > affecting the very high feed impedance at the base. The shield could be > used as the actual vertical antenna lead. I did not use the word "shield" or "sleeve". I said he could run the control wires up inside a hollow 1/4WL radiator feeding the rest of the half-square. Note that the two original antenna leads were completely removed. The tubing becomes the radiator. Here's the diagram of what I suggested where "RFC" is an RF choke with RF bypass caps at A-B and C-D. FP is the half-square feedpoint. FP 1/4 WL radiator 3/4WL ======================tubing=========================+---wire A--RFC----------------------wire-----------------RFC--C--relay B--RFC----------------------wire-----------------RFC--D--coil ======================tubing========================= It is my contention that the RFCs located just inside the tubing at both ends will prevent this configuration from acting like a stub and that there will be little RF EM energy inside the tubing. How many functional stubs has anyone seen with two RF chokes in the conducting path? > Now I know to many people the problem is obvious. The problem is the > IMPEDANCE of the open stub formed at the bottom of the vertical sleeve > by the inner wire that has to go to a control system of some type and > the outer sleeve. All DC circuits isolated by RF chokes inside the tubing and bypass caps across points A-B and C-D. > That impedance has to be many ten's of kilo ohms so the shunting > impedance is high compared to the impedance of the sleeve. > > Full RF voltage of the feedpoint is also across the gap where the > center wires leave the shield. That's where the RF chokes are located inside the tubing. what happens when RF voltage encounters an RF choke? > In order for the shield to have some meaningful effect on the system > other than simply running the wires down in parallel with the fed wire, > the impedance between the inner wire and shield must be VERY high at > the bottom. It can of course be a SHORT at the top, since the relay > just sits up there in the air with only the contacts making a > connection, so the top is easy to handle with some bypass caps. But that wasn't the configuration I suggested. > What Cecil totally misses is he formed what is in effect the electrical > equivalent of a sleeve balun. Please explain how a sleeve balun functions with two RF chokes installed in the conducting path. > The velocity factor of the transmission > line forming this stub has to be the SAME as the outside of the sleeve > so the INSIDE is 1/4 wl long electrical, and the the loss has to be > very low. Otherwise the common mode impedance of the relay wires > exiting the shield will not be several times higher than the antenna > feed impedance, which is several k-ohms. The impedance of the RF chokes is also pretty high. > I've seen antenna manufacturers make the same mistake Cecil just made, > and assume that running a cable down the center of a "hot" mast that is > part of an antenna means the wires have zero current and zero effect > since they are inside the shield, but anyone with any understanding of > how the system works would catch the flaws in this idea right away. Don't forget the RF chokes inside the tubing and bypass caps where the wires enter and exit the tubing. > The flaw is the differential IMPEDANCE between the shield and the shell > forming an antenna has to be several times the common mode impedance of > the shell or the system won't be worth a flip. Without that high > impedance, the inner wire might as well just run down the outside of > the sleeve and a couple good HV high impedance RF chokes be used to > supply relay control voltage. RF chokes at each end present a pretty high series impedance. The RF current at each end is virtually zero and the wires are a non- resonant length. > As a matter of fact at AM BC stations, when using two way or RPU > antennas on the hot base insulated towers, I never bothered with > running the cables INSIDE the tower. We weren't talking about a tower. We were talking about solid tubing made from copper or aluminum. > Cecil will catch on with help I'm sure, I just don't have time to walk > him through the problem step by step. I'm willing to learn but you cannot simply assert something that seems to violate the laws of physics and then say you don't have time to explain it or furnish a reference. Please explain how a stub can be functional with two RF chokes in the conductive path. I know you have a bunch of followers who consider your word to be gospel and depend upon nothing except faith for their belief in you, but I am not one of them. -- 73, Cecil http://www.qsl.net/w5dxp From k6mhek6mhecom> Newsgroups: rec.radio.amateur.antenna Subject: Re: Quarterwave vertical with radials Date: Tue, 11 Jul 2006 07:09:08 -0700 Message-ID: References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> <1152609735.071204.264590@m79g2000cwm.googlegroups.com> X-Newsreader: Forte Agent 1.93/32.576 English (American) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 16 NNTP-Posting-Host: 68.64.59.124 X-Trace: sv3-lOtQpy1JE5dATIkXEsJ4Pll8uhoAS2VTZ5E3qU52uRa8jICCJEZUUzYGcpH5gg9ZH9QU5ZtFZhdPL6V!ifYoxjH6w6s18POKnCeTBqVlbi0NVpw2vbGZ3Z8M9UTfHIhQTE+K2OckSUyMhtltBFejAkcv4F/f!/kQJP8hXstWQTyPCWOa8 X-Complaints-To: abuse@adelphia.net X-DMCA-Complaints-To: copyright@adelphia.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.32 Path: news.unc.edu!elk.ncren.net!canoe.uoregon.edu!cyclone1.gnilink.net!gnilink.net!peer01.cox.net!cox.net!border2.nntp.dca.giganews.com!nntp.giganews.com!local01.nntp.dca.giganews.com!nntp.adelphia.com!news.adelphia.com.POSTED!not-for-mail Xref: news0.isis.unc.edu rec.radio.amateur.antenna:226298 On Tue, 11 Jul 2006 14:35:34 +0100, "Reg Edwards" wrote: >What's the matter with 3, equi-spaced radials? > >Be economical. Save a radial! It looks better too. And there are no >arguments about directionality. >---- >Reg. Modeling such an arrangement gave no real noticeable difference between using three or four radials. Danny, K6MHE Article: 226299 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <-KSdnXVeB9D7DS7ZRVnyrQ@bt.com> Message-ID: Date: Tue, 11 Jul 2006 14:10:49 GMT Reg Edwards wrote: >>Reg Edwards wrote: >> >>>A pair of radials behave as a continuous dipole fed at its center > > via > >>>a single wire. And it radiates. >> >>If the radials are horizontal and radiating, why is >>there virtually no horizontally polarized radiation? >>-- >>73, Cecil > > ====================================== > Cec, > Your use of the word "virtually" indicates a weakness in your ideas on > the subject. > > The radiation, as small as it may be, is vertically polarised. > ---- > Reg. > > Put a number on it, Reg. Besides, you said, yourself, that Cecil is always right. 73, Tom Donaly, KA6RUH Article: 226300 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 14:22:20 GMT Cecil Moore wrote: > Tom Donaly wrote: > >> w8ji@akorn.net wrote: >> >>> Cecil Moore wrote: >>> >>>> It's pretty easy to understand. Any two radials, >>>> 180 degrees apart and high enough, should theoretically >>>> cancel each other's radiation in the far field. >>> >>> >>> Not true. >> >> >> How much not true? > > > -45 DB, i.e. negligibly not true. :-) That's what I thought. Sometimes, orders of magnitude are important. Otherwise, people would be worrying about the fact that they're closer to the center of the Earth in the middle of the bottom of a flat bottomed hole than they are at the edges. 73, Tom Donaly, KA6RUH Article: 226301 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> Message-ID: Date: Tue, 11 Jul 2006 14:23:29 GMT John Popelish wrote: > Tom Donaly wrote: > >> How many photons does it take to make a Watt? > > > 1/(Hz*6.63*10^-34). > > The lower the frequency the less energy per photon. That's joules per second, is it? 73, Tom Donaly, KA6RUH Article: 226302 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Induced signal? Date: 11 Jul 2006 07:46:49 -0700 Message-ID: <1152629209.083797.157250@m79g2000cwm.googlegroups.com> References: I reran my EZNEC coax model with a cage with an octagon loop every foot in height... This is a pretty good shield at 40m, I think. The holes are .002x.007 wavelength. The difference is apparent. Not much confidence that this is modeling the problem... but maybe it's better: Ran it with wire inside/outside the shield. Did #2 wire this time to simulate thin wire down the center of a pipe. Before, the inside/outside comparison yielded almost identical results. Now it doesn't... Wire 6 inches outside shield: Wire No. 26: Segment Conn Magnitude (A.) Phase (Deg.) 1 Open .00356 86.70 2 .00776 95.54 3 .01039 103.14 4 .01208 109.03 5 .01323 117.85 6 .01373 126.69 7 .01297 133.85 8 .01159 144.14 9 Open .00684 154.69 Wire centered in shield: Wire No. 26: Segment Conn Magnitude (A.) Phase (Deg.) 1 Open .00201 53.19 2 .00298 65.98 3 .00324 71.00 4 .00509 45.58 5 .00387 78.85 6 .00401 118.35 7 .00308 63.54 8 .00347 137.70 9 Open .00503 164.46 Anyway, the point that the original cage was a bad model is taken. An additional approximation toward a full shield changes things a great deal. Should anyone want to take a look: http://www.n3ox.net/cage_coax.ez Dan Article: 226303 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Induced signal? Date: 11 Jul 2006 07:49:34 -0700 Message-ID: <1152629374.119641.242380@s13g2000cwa.googlegroups.com> References: Oh, the laws of physics don't preclude RF from getting in the ends of a piece of coax, by the way. There is no minimum cutoff frequency for the TEM mode in coaxial waveguide. There is in hollow waveguide with no center conductor. You still need to be able to couple to the ends, and a floating center conductor is not the best way to couple energy in. However, there's no fundamental physical reason why currents *won't* flow on the center conductor in an open-ended piece of coax. Dan Article: 226304 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 10:58:07 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> Message-ID: Cecil Moore wrote: > John Popelish wrote: > >> Remember, it is Cecil, not me, who demands agreement or eternal verbal >> torture. > > > I don't demand agreement, John, just resolution. Resolution in who's mind? I don't demand anything. I just read, occasionally throw out a thought, and learn what I can. I accept that sometimes I will learn something that is wrong, but I just keep trying to fit the pieces together. Article: 226305 of rec.radio.amateur.antenna Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If Necesssary. From: "John Jowdy" Date: Tue, 11 Jul 2006 10:57:13 -0400 Message-ID: References: <4n6ql.jaf.19.1@news.alt.net> I can already detect a vast improvement, keep up the good work and good luck in the contest. W1AW, Rick Lindquist "Paul Willie Schleck" wrote in message news:4n6ql.jaf.19.1@news.alt.net... > Warning. I, Paul W Schreck, blowgut of blowguts, and self-appointed > moderator, will be monitoring these newsgroups for inappropriate > statements, > misuse of the groups, cross-posting and foul language and will be saving > and > archiving your comments for future use. > > Any future and wanton misuse of my name or callsign or forgeries thereof > will be recorded as well. > > I will not hesitate to contact aeiou.com, wxyz, CBS, NBC, BBC or Altopia, > or > any other provider to turn you and your cohorts in for punitive action. > > While these groups are largely unmoderated, I am here to tell you that > there > is a new Sheriff in town, and the Sheriff is me. > > > > You have been warned. Conduct yourself accordingly or risk losing your > ISP. > > > > Paul W. Schreck, Self Appointed Moderator Supreme, New Sheriff. > > Hissyfits@novia.nel > > www.blowguts.com > > > > > > Article: 226306 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 11:06:19 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> Message-ID: Tom Donaly wrote: > John Popelish wrote: > >> Tom Donaly wrote: >> >>> How many photons does it take to make a Watt? >> >> >> >> 1/(Hz*6.63*10^-34). >> >> The lower the frequency the less energy per photon. > > > That's joules per second, is it? A watt is a joule per second. The formula gives the number of photons per second that carry a watt (or a joule per second) once you provide the Hz (frequency). By the way, I am having second thoughts as to whether or not there should be a 2*pi factor in there, since most physics formulas deal with frequency in radians per second, not cycles per second. But the photon energy formulas usually deal with wavelength, and I have never seen one that assumes a wavelength is a radian of a cycle, rather that a full cycle, so, perhaps Hz is the correct unit. If anyone can clear this up for me, I would appreciate it. Article: 226307 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> <1152609735.071204.264590@m79g2000cwm.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 15:04:42 GMT w8ji@akorn.net wrote: > Cecil Moore wrote: >> A free space vertical with horizontal radials in EZNEC >> has horizontal radiation more than 40 dB down from the >> vertical radiation. That's a high degree of cancellation. > > The issue is the horizontal opposing radials only have that degree of > cancellation for perfectly horizontal directions. That's the issue? Something that no one has ever asserted otherwise? > You will be able to see your statement isn't true if you place the > antenna in freespace and look at pattern distortion at various > elevation angles. For example, the 2-d plot is skewed 2.11 dB from > being circular at - 45 and +45 degrees elevation. The skewing gets > worse at larger angles from the plane of the radials. Just ran that test. There was 0.02 dB difference at +45 and -45. > If the radials were REALLY radiating -40dB in all directions as you > wrongly assume, there would NOT be significant FS change in the azimuth > pattern at various elevations. There is no significant FS change according to EZNEC. > You looked at horizontal radiation, but the horizontal radials peak > radiation is vertically polarized and nearly off the radial's ends. > (Just like in a dipole pattern.) Unfortunately for that argument, the radiating currents in a dipole are in phase, i.e. designed for maximum radiation. The radiating currents in symmetrical radials are 180 degrees out of phase, i.e. designed for minimum radiation. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226308 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: Need help on QRM rejection ( WITHOUT A BEAM !!) References: Message-ID: Date: Tue, 11 Jul 2006 10:00:01 -0500 Hi Chas No doubt I will be mentioning stuff you have already tried and tested... I assume you mean QRN rather than QRM? - It is probably worthwhile seeking out the source of the noise. Such things as turning house equipment off and listening etc. I have horrendous QRN here (Longview East Texas) from power line noise. It is worse of course on HF but it does interfere with weak signal work on 2m. The noise dissappears during and about an hour after rain... I have already done a walkaround with the 2m SSB RX to determine where the source is (pole hardware near a oil pump about 200 yards away) but havent contacted the power company yet. (Keep in mind that by law they are obliged to fix it. The FCC apparently helps a lot here. Your MARS status will probably make a big difference as well) - Most radios are very good at reducing pulse noise like from a car ignition. My oldish Kenwood radio also does a credible job on the PLI at the expense of some selectivity. It may be worthwhile having a play with the noise blanker circuit to also suppress noise with a slower rise time (like PLI). You may also want to try using a separate sense antenna and amplifier into the NB circuit. If your blanker isnt affecting the noise you may need to increase its sensitivity. (make it adjustable though!) - If you are message handling only, a digital mode (like Olivia, PSK etc) will go a long way to getting the signal through. Useless of course if you are phone/radio patching families.. - Yes I agree, try another RX to see if the S/N is any better. If it is then the first radio might have some problems. - Elsewhere on this group you will have seen a discussion on noise reduction techniques using antennas. I wont repeat it here. I am sure you know the vertical is "noisiest" and a pure horizontal dipole is "quietest". Perhaps the inverted V construction is responding to the local noise more than a straight horizontal antenna. Using a separate low antenna (often a magloop) for RX can also yield much better S/N than using a highly placed one. Since noise level generally on HF is much higher than the RX sensitivity this can work very well. It isnt a viable solution (say) from 10M and up through VHF/UHF - External DSP might be viable. You can get software nowadays that will take the radio's audio output and "wash it". It is much better to use the IF for DSP but PC soundcards can only sample at 44kHz or so. I havent dabbled in this much but for Windows have a look at http://www.qsl.net/dl4yhf/spectra1.html and see if it helps. Of course your PC power supply etc may then cause a problem! - If you have one noise source that looks like a point source radiator (ie not power lines) phase cancellation techniques might work. ie using a second antenna and a passive phase delay circuit tune for max s/n by adding the noise to itself 180 degrees out of phase. - Your feed system might be responding to signal. I dont know the antenna design you mentioned but unbalanced "balanced feeder" tends to radiate as well as receive and since it is vertical will respond to noise. A balun is the supposed trick here but I am sure others will jump on this often contentious topic. Like I first mentioned try to find the location of the noise source. If it is some power lines or a known location put up your windom such that a nul is pointing in the noise source direction or at least not parallel to power lines. Hope this helps Cheers Bob W5/VK2YQA East Texas chasm@texas.net wrote: > > I am working with MARS on 75m. I am seeing some horrific QRM esp today but > generally every day and definitely need some help on rejecting the noise. > Article: 226309 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> Message-ID: <53rco3-rti.ln1@p400bob.personal.cox.net> Date: Tue, 11 Jul 2006 10:01:25 -0500 Yes! I think EZNEC has a optimization function as you stated. I know 4NEC2 does as I have used it many times.. Cheers Bob VK2YQA JC wrote: > Is there a software which can design an antenna (like EZNEC or similar ) > then allows to automatically optimize its dimensions according to given > requirements: max gain, F/B, min swr... and accepted dimensional parameters > changes: boom length, spacing.... > JC > > Article: 226310 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Voltage feeding a VHF yagi References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> <6cjvn3-s7p.ln1@p400bob.personal.cox.net> <1152218809.770077.3670@s26g2000cwa.googlegroups.com> <1152222378.456155.303810@j8g2000cwa.googlegroups.com> <1152233762.848358.152070@s13g2000cwa.googlegroups.com> <1152578671.148819.275420@b28g2000cwb.googlegroups.com> <1152609823.761832.13220@p79g2000cwp.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 15:06:05 GMT w8ji@akorn.net wrote: > Cecil Moore wrote: >> w8ji@akorn.net wrote: >>> The short doesn't affect CM currents. >> I1 >> +--<---A------------X----------------------------- >> | >> +--<---B------------Y >> I2 >> >> I1 and I2 are common-mode. What do you suppose will >> happen at the short? > > I know what happens. > The problem is what YOU are supposing happens. I'm supposing Kirchhoff's laws apply. What are you supposing? How is the above different from link coupling? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226311 of rec.radio.amateur.antenna From: "Reg Edwards" References: <44b3afc1$0$990$ba4acef3@news.orange.fr> Subject: Re: Antenna optimization Date: Tue, 11 Jul 2006 16:12:13 +0100 Message-ID: "JC" wrote in message news:44b3afc1$0$990$ba4acef3@news.orange.fr... > Is there a software which can design an antenna (like EZNEC or similar ) > then allows to automatically optimize its dimensions according to given > requirements: max gain, F/B, min swr... and accepted dimensional parameters > changes: boom length, spacing.... > JC ---------------------------------------------------------------------- ------- Dear JC, You don't need software. What you describe is non-existent anyway. What you want is a long experienced antenna designer who can be permanently engaged on your behalf. There are very few of such creatures about. You will have to be numerically quite specific about particular problems. And even then you will get solutions which, with luck, are probably only in the right ball-park. On the other hand, ball-park solutions are perfectly satisfactory. In the nature of events, no-one has ever solved an antenna problem which is other than in a ball-park. Fortunately, antennas work quite well even when in the wrong ball-park. Download a free copy of EZNEC and in a few months time you may have solved your first complicated, specific problem. As time goes on, you will become more adept and there will be no need to engage a long experienced antenna designer. You will have become one youself and can offer your services for hire. If you have a specific problem you may, if you are lucky, find a computer program written by someone who has already solved it. But its highly unlikely to be exactly the same problem. It will be in a somewhat different ball-park. Optimisation is out! You will have to contend with whatever you can get your hands on. What's been done before. Take it or leave it! ---- Reg. Article: 226312 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Induced signal? Date: 11 Jul 2006 08:17:39 -0700 Message-ID: <1152631059.662209.308680@35g2000cwc.googlegroups.com> References: I should add that sticking the wire even a little bit (six inches) out the ends of the skeleton shield increases the current on the center conductor... I expect that the situation with a long wire exiting the bottom will couple MUCH more energy into the center conductor. So, in the context of control wires up an antenna element, the wires coming away from the antenna and a load to represent a choke should be included. I'd also like to refine the shield mesh but I ran out of segments ! Dan Article: 226313 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Voltage feeding a VHF yagi Date: 11 Jul 2006 08:21:29 -0700 Message-ID: <1152631289.594334.34440@m73g2000cwd.googlegroups.com> References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> Cecil Moore wrote: > w8ji@akorn.net wrote: > > Cecil Moore wrote: > >> w8ji@akorn.net wrote: > >>> The short doesn't affect CM currents. > >> I1 > >> +--<---A------------X----------------------------- > >> | > >> +--<---B------------Y > >> I2 > >> > >> I1 and I2 are common-mode. What do you suppose will > >> happen at the short? > > > > I know what happens. > > The problem is what YOU are supposing happens. > > I'm supposing Kirchhoff's laws apply. What are you > supposing? How is the above different from link > coupling? > -- > 73, Cecil http://www.qsl.net/w5dxp\ Kirchoff's laws apply, but you're forgetting one conductor. ---<---A+B----coax braid-------------| Article: 226314 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Quarterwave vertical with radials Date: Tue, 11 Jul 2006 08:22:10 -0700 Message-ID: References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> On Mon, 10 Jul 2006 20:52:38 -0400, John Popelish wrote: >Not much to discuss. I don't do such calculations often, but I get >about 5*10^-27 joule per photon. What do you calculate their energy >to be? Hi John, Closer to 4.63 · 10^-27 joule. Not enough difference to matter. So, we are talking about a little more than 10^28 photons and when we return to your statement (or is it twice that?) >>>I didn't mean that the mirror produces half of the total photons that are radiated. or >>> I meant that half as many photons are produced, compared to the >>>full dipole antenna that produces the same fields above the center line. I have to again exclaim: >> No, I suppose not. Further, as to your "stipulation:" >>> the field strength above the centerline >>>being constant, rather than the radiated power. I missed that we were >>>only talking about a case of radiating 100 watts. It would be strange to talk about radiation without some expression of power to the antenna. 100 watts has been a cardinal value in this group for many years. Field strength is generally expressed in volts/meter. Somehow, its translation into eV to follow the photon metaphor seems rather strained. Going further with this convolution of centerline partition that relates to same fields (same?) to explain a difference is also quite odd. Would you care to elaborate on this concept of the centerline? >Do you have some point? This is odder yet, you introduce the topic and ask me what my point is? My own separate observation is the introduction of photonics doesn't add much does it? >> Hard to escape, and makes a mess of describing mirrors too, especially >> when they are skeletal approximations as well. > >You have to start understanding mirrors, somewhere. Perhaps you >prefer a different starting point. There are several. Starting with radials would seem to be in keeping with the thread. Shifting starts when you haven't finished seems to defeat the progression of where you were going. >> I can offer more thread-busters when it comes to photonics, but that >> is a slam dunk. Get us rolling on one ace proposition, and I will get >> back to you in a couple of hours. > >I have no idea what you are saying with these two sentences. No doubt. I read these same admissions with some frequency. It rarely keeps me up at nights worrying anymore. You were going to tie this all together weren't you? 73's Richard Clark, KB7QHC Article: 226315 of rec.radio.amateur.antenna From: "Reg Edwards" References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> <1152609735.071204.264590@m79g2000cwm.googlegroups.com> Subject: Re: Quarterwave vertical with radials Date: Tue, 11 Jul 2006 16:32:15 +0100 Message-ID: "Dan Richardson wrote > wrote: > > >What's the matter with 3, equi-spaced radials? > > > >Be economical. Save a radial! It looks better too. And there are no > >arguments about directionality. > >---- > >Reg. > > Modeling such an arrangement gave no real noticeable difference > between using three or four radials. ========================================= Of course it didn't. That's the point I was making. The number of radials, from 1 to N, is immaterial. As N increases there will be a slight improvement in radiating efficiency. The N loss resistances are all in parallel as seen by the feedline. ---- Reg. Article: 226316 of rec.radio.amateur.antenna From: wood@itd.nrl.navy.mil (J. B. Wood) Subject: Re: EZNEC Question Date: Tue, 11 Jul 2006 11:44:59 -0400 Message-ID: References: <12b0snu32ufisd2@corp.supernews.com> <44B11F25.1010108@fuse.net> In article <44B11F25.1010108@fuse.net>, jawod wrote: > Roy, > > I just wanted to butt in to say that your EZNEC is a fine program. Just > started playing with it (ARRL version). Very user friendly...and your > "test drive" is phenomenal. > > I must say, since I left ham radio back in the late 70's, I am very > surprised that antenna modeling is within the reach of someone of > limited technical background like me. > > Great job! > You've done a lot for my "new" favorite hobby. > > Thanks! > > John > AB8WH > > PS, I will be purchasing the full program. Hello, and as long as kudos are being handed out I thought I'd jump in and say that while programs like EZNEC add some user-friendliness and graphical capability they rely on the NEC (usually NEC-2) engine. For NEC-1, NEC-2 and NEC-4 Gerald Burke and others at the Lawrence Livermore Lab deserve a lion's share of credit for drafting user documentation, correcting bugs and enhancing code that was originally done in the early '70s by MBAssociates for the U.S. Naval Research Laboratory (NRL). Just a bit of NEC history. Sincerely, and 73s from N4GGO, John Wood (Code 5550) e-mail: wood@itd.nrl.navy.mil Naval Research Laboratory 4555 Overlook Avenue, SW Washington, DC 20375-5337 Article: 226317 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Quarterwave vertical with radials Date: Tue, 11 Jul 2006 08:43:15 -0700 Message-ID: <0hh7b2hripqflrgs3flvc9jul45m45nqlg@4ax.com> References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> On Tue, 11 Jul 2006 11:06:19 -0400, John Popelish wrote: >By the way, I am having second thoughts as to whether or not there >should be a 2*pi factor in there, since most physics formulas deal >with frequency in radians per second, not cycles per second. But the >photon energy formulas usually deal with wavelength, and I have never >seen one that assumes a wavelength is a radian of a cycle, rather that >a full cycle, so, perhaps Hz is the correct unit. > >If anyone can clear this up for me, I would appreciate it. Hi John, That would be 2 pi radians per second as frequency - same thing as a cycle. For photonic interactions the classic treatment is usually with wavenumber as frequency not cycles nor radians. However, the 2 pi difference is the difference between the Planck constant represented as h, and its rational equivalent (with 2 pi divided out) of h-bar. 73's Richard Clark, KB7QHC Article: 226318 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 12:36:18 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> Message-ID: <-9ydnShC5I44TC7ZnZ2dnUVZ_umdnZ2d@adelphia.com> Richard Clark wrote: > On Mon, 10 Jul 2006 20:52:38 -0400, John Popelish > wrote: (snip) >>>>I meant that half as many photons are produced, compared to the >>>>full dipole antenna that produces the same fields above the center line. > > > I have to again exclaim: > > >>>No, I suppose not. > > > Further, as to your "stipulation:" > >>>>the field strength above the centerline >>>>being constant, rather than the radiated power. I missed that we were >>>>only talking about a case of radiating 100 watts. > > > It would be strange to talk about radiation without some expression of > power to the antenna. 100 watts has been a cardinal value in this > group for many years. Field strength is generally expressed in > volts/meter. Somehow, its translation into eV to follow the photon > metaphor seems rather strained. Going further with this convolution > of centerline partition that relates to same fields (same?) to explain > a difference is also quite odd. Would you care to elaborate on this > concept of the centerline? The center line I am referring to is the mirror line of the ground plane or radial group that allows a monopole to have a field pattern (both E and H) above that mirror line, that would exist there, if the antenna was a symmetrical dipole. Without the mirror effect, the field pattern of the monopole depends on the path the feed line takes away from the monopole, and any other conductive objects nearby. Since I am talking about field patterns, it seemed natural to switch >from total radiated watts to field intensities and the photons that field emits and where those photons head. >>Do you have some point? I see that you snipped the line of nonsense you originally posted that prompted this question. You asked, "Should we discuss how infinitesimal the energy is in a 40M photon? (Easily accounts for why so many are needed for that same 100W.) No, I suppose not. " So I asked if asking a question and dismissing it made some point. > This is odder yet, you introduce the topic and ask me what my point > is? My own separate observation is the introduction of photonics > doesn't add much does it? While amateurs may ultimately be interested in radiating power in particular directions, we are discussing the physics of the radiation process, and photonics is one way to think about that process. >>>Hard to escape, and makes a mess of describing mirrors too, especially >>>when they are skeletal approximations as well. >> >>You have to start understanding mirrors, somewhere. Perhaps you >>prefer a different starting point. There are several. > > > Starting with radials would seem to be in keeping with the thread. > Shifting starts when you haven't finished seems to defeat the > progression of where you were going. The ultimate radial pattern is a solid disk. Once you understand what that does to the field pattern, you can start toward a radial wire layer, and see how, in important ways, like the ability to carry radial current, it resembles a disk. Then, you can explore how reducing the number of radials alters the approximation. >>>I can offer more thread-busters when it comes to photonics, but that >>>is a slam dunk. Get us rolling on one ace proposition, and I will get >>>back to you in a couple of hours. >> >>I have no idea what you are saying with these two sentences. > > No doubt. I read these same admissions with some frequency. It > rarely keeps me up at nights worrying anymore. I find that unsurprising. Your posts do not seem addressed to me or others, so much as to yourself. > You were going to tie this all together weren't you? Probably not, since I am working through the process in my own mind. I am not the teacher so much as a student trying to learn something useful. I hope my posts generate more useful discussion from others than I have gotten from you, so far. Article: 226319 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 12:37:44 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> <0hh7b2hripqflrgs3flvc9jul45m45nqlg@4ax.com> Message-ID: <-9ydnStC5I5hTC7ZnZ2dnUVZ_umdnZ2d@adelphia.com> Richard Clark wrote: > On Tue, 11 Jul 2006 11:06:19 -0400, John Popelish > wrote: > > >>By the way, I am having second thoughts as to whether or not there >>should be a 2*pi factor in there, since most physics formulas deal >>with frequency in radians per second, not cycles per second. But the >>photon energy formulas usually deal with wavelength, and I have never >>seen one that assumes a wavelength is a radian of a cycle, rather that >>a full cycle, so, perhaps Hz is the correct unit. >> >>If anyone can clear this up for me, I would appreciate it. > > > Hi John, > > That would be 2 pi radians per second as frequency - same thing as a > cycle. For photonic interactions the classic treatment is usually > with wavenumber as frequency not cycles nor radians. However, the 2 > pi difference is the difference between the Planck constant > represented as h, and its rational equivalent (with 2 pi divided out) > of h-bar. Thank you. Makes good sense. Article: 226320 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 12:42:23 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> Message-ID: <56ydnS7kNPiOTi7ZnZ2dnUVZ_q6dnZ2d@adelphia.com> Cecil Moore wrote: > John Popelish wrote: > >> Cecil Moore wrote: >> >>> I don't demand agreement, John, just resolution. >> >> Resolution in who's mind? > > In mine, of course. I am obsessive-compulsive that way. > Sorry about that - it's probably a character flaw. Then you also probably believe that a character flaw is an absolute, as are and evil. Article: 226321 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 12:45:25 -0400 From: John Popelish Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> <56ydnS7kNPiOTi7ZnZ2dnUVZ_q6dnZ2d@adelphia.com> Message-ID: <56ydnSnkNPhVTi7ZnZ2dnUVZ_q6dnZ2d@adelphia.com> John Popelish wrote: > Cecil Moore wrote: > >> John Popelish wrote: >> >>> Cecil Moore wrote: >>> >>>> I don't demand agreement, John, just resolution. >>> >>> >>> Resolution in who's mind? >> >> >> In mine, of course. I am obsessive-compulsive that way. >> Sorry about that - it's probably a character flaw. > > > Then you also probably believe that a character flaw is an absolute, as > are and evil. I dropped a word during editing. That should have read: Then you also probably believe that a character flaw is an absolute, as are good and evil. Article: 226322 of rec.radio.amateur.antenna From: "JC" References: <44b3afc1$0$990$ba4acef3@news.orange.fr> Subject: Re: Antenna optimization Date: Tue, 11 Jul 2006 18:37:32 +0200 Message-ID: <44b3d3d0$0$819$ba4acef3@news.orange.fr> Thanks for help, I think I wrongly explained my problem, here is the question: 1/ I design an antenna, for instance a 3 el 20m beam. 2/ I enter into EZNEC wires dimensions, spacing, height, source..... 3/ EZNEC calculates gain, F/B, SWR....and results are acceptable. 4/ Now let's suppose my objectives are max F/B as I have a QRM source opposed to my favourite transmitting direction and SWR< 1.5 on a given frequency range as my transceiver is very SWR sensitive and I can't use an antenna tuner. I accept changing wire lengths and spacing but not boom length. Is there a way to have EZNEC, or another software, doing automatic iterations until it reaches the best F/B-SWR compromise ? JC - F8ND "Reg Edwards" a écrit dans le message de news: RtGdnYQxPcYGXS7ZnZ2dnUVZ8qGdnZ2d@bt.com... > > "JC" wrote in message > news:44b3afc1$0$990$ba4acef3@news.orange.fr... >> Is there a software which can design an antenna (like EZNEC or > similar ) >> then allows to automatically optimize its dimensions according to > given >> requirements: max gain, F/B, min swr... and accepted dimensional > parameters >> changes: boom length, spacing.... >> JC > ---------------------------------------------------------------------- > ------- > Dear JC, > > You don't need software. What you describe is non-existent anyway. > What you want is a long experienced antenna designer who can be > permanently engaged on your behalf. There are very few of such > creatures about. > > You will have to be numerically quite specific about particular > problems. And even then you will get solutions which, with luck, are > probably only in the right ball-park. > > On the other hand, ball-park solutions are perfectly satisfactory. In > the nature of events, no-one has ever solved an antenna problem which > is other than in a ball-park. Fortunately, antennas work quite well > even when in the wrong ball-park. > > Download a free copy of EZNEC and in a few months time you may have > solved your first complicated, specific problem. As time goes on, you > will become more adept and there will be no need to engage a long > experienced antenna designer. You will have become one youself and > can offer your services for hire. > > If you have a specific problem you may, if you are lucky, find a > computer program written by someone who has already solved it. But its > highly unlikely to be exactly the same problem. It will be in a > somewhat different ball-park. > > Optimisation is out! You will have to contend with whatever you can > get your hands on. What's been done before. Take it or leave it! > ---- > Reg. > > Article: 226323 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <-KSdnXVeB9D7DS7ZRVnyrQ@bt.com> Message-ID: <4tQsg.63576$Lm5.14289@newssvr12.news.prodigy.com> Date: Tue, 11 Jul 2006 16:37:20 GMT Cecil Moore wrote: > Tom Donaly wrote: > >> Besides, you said, yourself, that Cecil >> is always right. > > > False. Reg didn't say that. He said it under his breath as he was writing it to this newsgroup. 73, Tom Donaly, KA6RUH Article: 226324 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <-KSdnXVeB9D7DS7ZRVnyrQ@bt.com> <4tQsg.63576$Lm5.14289@newssvr12.news.prodigy.com> Message-ID: <1WQsg.2049$2v.2030@newssvr25.news.prodigy.net> Date: Tue, 11 Jul 2006 17:08:13 GMT Tom Donaly wrote: > Cecil Moore wrote: >> Tom Donaly wrote: >>> Besides, you said, yourself, that Cecil >>> is always right. >> >> False. Reg didn't say that. > > He said it under his breath as he was writing it to this > newsgroup. If Reg actually believed that, he wouldn't argue with me so much. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 226325 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Induced signal? Date: Tue, 11 Jul 2006 10:10:38 -0700 Message-ID: References: <1152607665.959599.175290@s13g2000cwa.googlegroups.com> <1152629209.083797.157250@m79g2000cwm.googlegroups.com> On 11 Jul 2006 07:46:49 -0700, "n3ox.dan@gmail.com" wrote: >Should anyone want to take a look: http://www.n3ox.net/cage_coax.ez Hi Dan, Thanx for the work. 73's Richard Clark, KB7QHC Article: 226326 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> <56ydnS7kNPiOTi7ZnZ2dnUVZ_q6dnZ2d@adelphia.com> Message-ID: Date: Tue, 11 Jul 2006 17:15:50 GMT John Popelish wrote: > Cecil Moore wrote: >> I am obsessive-compulsive that way. >> Sorry about that - it's probably a character flaw. > > Then you also probably believe that a character flaw is an absolute, as > are (good) and evil. "If it's not a 'one' or a 'zero', it's broke." :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 226327 of rec.radio.amateur.antenna From: w0zv@yahoo.com Subject: Re: Antenna optimization Date: 11 Jul 2006 10:31:25 -0700 Message-ID: <1152639085.369972.127940@m79g2000cwm.googlegroups.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> JC wrote: > 4/ Now let's suppose my objectives are max F/B as I have a QRM source > opposed to my favourite transmitting direction and SWR< 1.5 on a given > frequency range as my transceiver is very SWR sensitive and I can't use an > antenna tuner. > I accept changing wire lengths and spacing but not boom length. > Is there a way to have EZNEC, or another software, doing automatic > iterations until it reaches the best F/B-SWR compromise ? K6STI's Yagi Optimizer 7.0 does a very nice job of this. You can choose the weighting of Gain, F/R, SWR or Impedance and optimize over any choice of frequencies. See my results for a pair of stacked KLM Yagis on 28 MHz here: http://users.vnet.net/btippett/yagi_optimizer_7_0.htm Unfortunately K6STI no longer markets his software to hams (due to software piracy issues). Hopefully you can find someone with a copy who can optimize your initial results. 73, Bill W4ZV Article: 226328 of rec.radio.amateur.antenna From: nm5k@wt.net Subject: Re: Quarterwave vertical with radials Date: 11 Jul 2006 10:37:44 -0700 Message-ID: <1152639464.159051.159380@m79g2000cwm.googlegroups.com> References: Ron wrote: > Ok I am getting confused. You are saying that a groundplane will not > work as good a a ground mounted vertical ? At what angle are you > talking about? Are you more interested in working 500 miles or 6,000 > miles? > > Ron Nope. I think the elevated ground plane is superior to the ground mount as long as it's high enough in the air to avoid excess ground loss. As far as long haul, there may not be too large a difference if each system is equal as far as ground loss. IE: a ground mount with 120 radials, and a GP at 1/2 wave high with 4 radials should show about the same efficiency. So for long haul dx, they should be fairly close in theory. But... You have a better ground/space wave with the elevated antenna. This can come in handy when talking 50-100 miles away when the band doesn't support NVIS with a dipole, etc.. When you run the elevated antenna, you must always think of height in terms of wavelength, not feet or meters. A 2 meter GP can be fairly low, and still very efficient. But not a low band GP. A half wave is a different height on each band. Being I recommend a minimum of 1/4 wave height when using only 4 radials, that can be pretty high on a lower frequency. On 40m, I ran one at 36 ft at the base of the radiator. Thats just over 1/4 wave up. If I ran the same antenna on 80m, I would have to mount it at 72 ft to have the same efficiency. About 145 ft on 160m. Soooo...If you can't go that high, you must increase the number of radials to lower the ground losses to a equal number. If you have a ground mount with 120 radials, you need about 60 radials if the antenna is at 1/8 wave. About 8-12 radials if the antenna is at 1/4 wave. About 3-4 radials if the antenna is at 1/2 wave. All these have the same appx ground losses. So you can see, if you run a 80m ground plane at 15 ft, the ground losses will be high unless you use a whole lot of radials. So in that case, it's really more practical to use the ground mount unless you don't mind all that wire in the air. But equal loss ground mount vs ground plane? I'd take the ground plane anyday... I ran one on 40m and it kicked serious butt on long haul dx. And yes, I use the verticals on the low bands for mostly long haul. I use dipoles, etc for NVIS. MK Article: 226329 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 13:48:53 -0400 From: Dave Subject: Re: Need help on QRM rejection ( WITHOUT A BEAM !!) References: Message-ID: chasm@texas.net wrote: > I am working with MARS on 75m. I am seeing some horrific QRM esp today but > generally every day and definitely need some help on rejecting the noise. > SNIPPED A simple question. Are you hearing QRM, [M]anmade interference, heterodynes, whistles, etc? Or, are you hearing lots of static QRN? [N]atural noise sources? Article: 226330 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Radial versus reflection Date: Tue, 11 Jul 2006 10:56:38 -0700 Message-ID: <12b7pimrromv713@corp.supernews.com> References: <1152581628.528396.6170@m73g2000cwd.googlegroups.com> <12b62s9dgqj28af@corp.supernews.com> <1152585655.191122.52130@m73g2000cwd.googlegroups.com> pierred1@sympatico.ca wrote: > Roy Lewallen wrote: >> pierred1@sympatico.ca wrote: >> Note the qualification "low-angle" in the sentence you quoted. >> radiations going downward at a steep angle will be reflected off the >> ground plane. I tried to explain this in my previous postings, but >> apparently wasn't successful. >> >> Roy Lewallen, W7EL > > Roy, about the example from another subject, you (correctly) > illustrated that any radiation for an angle of 26 degrees or less will > be beyond the radial field > > But what about an angle of say 35 deg below horizon? That ray would > bounce on the radial field, is'nt it?? That 35 deg is an example of a > ''steep angle'' Yes, that's correct. With the caution, of course, that the general explanation is highly simplified. Roy Lewallen, W7EL Article: 226331 of rec.radio.amateur.antenna From: "Frank" References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> Subject: Re: Antenna optimization Message-ID: <1IRsg.107741$A8.25309@clgrps12> Date: Tue, 11 Jul 2006 18:01:33 GMT > Unfortunately K6STI no longer markets his software to hams (due to > software piracy issues). Hopefully you can find someone with a copy > who can optimize your initial results. > > 73, Bill W4ZV > You could try ARRL's "YW", available with the "Antenna Book". Frank Article: 226332 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: New Swiss antenna system... Date: Tue, 11 Jul 2006 11:09:40 -0700 Message-ID: <12b7qb5ohcdhk5b@corp.supernews.com> References: <1152588973.511463.222930@p79g2000cwp.googlegroups.com> One of the basic principles of the cellular telephone system is that the same parts of the spectrum can be used by many phones at once. This is possible only because each cell covers only a limited area. High spots which cover huge areas are pretty common -- just look at typical repeater or TV/FM broadcasting locations. But you won't find cell phone installations there except in very sparsely populated areas, and for very good reason -- there simply isn't anywhere near enough spectrum space available to accommodate all the users within range. Figuring out how to cram a couple of orders of magnitude more users into the same already-packed and efficiently used spectrum must be one of those "technological hurdles" yet to be overcome. But in the meantime, I'm sure Alavi is living quite well off the money >from the naive investors which never seem to be in short supply. Roy Lewallen, W7EL Article: 226333 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 11:22:05 -0700 Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers If From: Don Bowey Message-ID: References: <4n6ql.jaf.19.1@news.alt.net> On 7/11/06 7:57 AM, in article e90e8c$32e$1@news04.infoave.net, "John Jowdy" wrote: > I can already detect a vast improvement, keep up the good work and good luck > in the contest. > > W1AW, Rick Lindquist > > > "Paul Willie Schleck" wrote in message > news:4n6ql.jaf.19.1@news.alt.net... >> Warning. I, Paul W Schreck, blowgut of blowguts, and self-appointed >> moderator, will be monitoring these newsgroups for inappropriate >> statements, >> misuse of the groups, cross-posting and foul language and will be saving >> and >> archiving your comments for future use. >> >> Any future and wanton misuse of my name or callsign or forgeries thereof >> will be recorded as well. >> >> I will not hesitate to contact aeiou.com, wxyz, CBS, NBC, BBC or Altopia, >> or >> any other provider to turn you and your cohorts in for punitive action. >> >> While these groups are largely unmoderated, I am here to tell you that >> there >> is a new Sheriff in town, and the Sheriff is me. >> >> >> >> You have been warned. Conduct yourself accordingly or risk losing your >> ISP. >> >> >> >> Paul W. Schreck, Self Appointed Moderator Supreme, New Sheriff. >> >> Hissyfits@novia.nel >> >> www.blowguts.com >> >> >> >> >> >> > > Hey Paul, Kiss mine, you officious ass. Go moderate a CB channel. Article: 226334 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Induced signal? Date: 11 Jul 2006 11:33:34 -0700 Message-ID: <1152642814.362640.247960@p79g2000cwp.googlegroups.com> References: I think it's just a matter of degree. The more RF chokes there are, the less current will flow. It would be a straightforward matter to add more wire to the model and include loads for bypass caps and chokes. In either case (wire inside or outside of the shield) good decoupling where the wire lead exits is going to be important. The model so far may suggest that being inside the shield is better than being outside... but without that lead trailing away from the antenna some distance, it's not time to conclude much about the relay+half square problem. The 40m coax monopole answer would seem to be "yes, there's current on the center conductor, but it's small and coupled in through the ends" If you're using the standard EZNEC, you're going to have to knock another section off the top of the cage... if you've got EZNEC+ then just add away... I may try it when I get home... knock another section off and try a control wire... Might have to send off my money to Roy and go for EZNEC+... I know I can get around segment limitations with other programs but I do like EZNEC. This is probably the ninth time since I got the program a few months ago that I've hit the segment limit ... i like meshing things... Gives me a question about the (EZ)NEC limitations... should I be watching out for fine 2D meshes? It seems to work OK in this case... the base impedance of the meshed monopole and the current distribution viewed on the segments all makes sense, and it seems to me that there's not much reason to doubt that the currents are calculated correctly in the mesh as long as it's not coarse with respect to a wavelength... any caveats in this regard? 73, Dan Article: 226335 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Voltage feeding a VHF yagi Date: 11 Jul 2006 11:52:40 -0700 Message-ID: <1152643960.102707.230980@35g2000cwc.googlegroups.com> References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> Instantaneous sum of the common mode currents at B (you can give it an overall minus sign if you want, but it's right for common mode): Current flowing toward B from X + Current flowing toward B from Y - current flowing out from B via coax shield - current flowing out from B via coax center conductor. All the common mode current on the coax will flow on the outside. So current flowing out from B via coax center conductor is zero. So current flowing on the coax braid = Current flowing from X to B + Current flowing from Y to B. Points A and B are one point except for the reactance of the short connecting them. Dan Article: 226336 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Induced signal? Date: 11 Jul 2006 11:54:04 -0700 Message-ID: <1152644044.457865.278650@75g2000cwc.googlegroups.com> References: Cecil Moore wrote: > n3ox.dan@gmail.com wrote: > > I expect that the situation with a long wire exiting the bottom will > > couple MUCH more energy into the center conductor. > > My suggested solution over on eHam.net included RF chokes > and RF bypass caps at each end of the tubing. > -- > 73, Cecil http://www.qsl.net/w5dxp Cecil, You put great faith in passing you Mensa exam. With that in mind, what possible difference does the shield make once the inner conductor is bypassed and choked at each end? In case you can't understand, the answer is NO difference. Without the chokes and bypasses, your idea won't work. With the chokes and bypasses, the idea isn't needed. The relay wire can run right down the mast with no ill effects. It's so basic and simple, even a Mensa member can follow it! 73 Tom Article: 226337 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Induced signal? Date: 11 Jul 2006 12:04:56 -0700 Message-ID: <1152644696.098566.325300@m79g2000cwm.googlegroups.com> References: n3ox.dan@gmail.com wrote: > I think it's just a matter of degree. The more RF chokes there are, > the less current will flow. > Gives me a question about the (EZ)NEC limitations... should I be > watching out for fine 2D meshes? It seems to work OK in this case... > the base impedance of the meshed monopole and the current distribution > viewed on the segments all makes sense, and it seems to me that there's > not much reason to doubt that the currents are calculated correctly in > the mesh as long as it's not coarse with respect to a wavelength... any > caveats in this regard? This is such a common basic circuit used in so many BC applications I can't believe people are modeling it! Clue: Draw it on paper. Draw a vertical conductor running up along an insulated base tower and attached at the top. Now feed the tower. How do you get the wire away from the tower at the bottom without shorting the insulator? Two ways: 1.) You form a 1/4 wl shorted stub with the wire, attaching it to the tower 1/4 wl away from the tower base, but spacing it away from the tower from that point downwards, either inside or outside the tower. In this case the dielectric has to be very good (like air) and the diameter of the tower has to be large compared to the wire if the wire is inside the tower. This is so the base inpedance open circuit impedance is very high compared to tower feed impedance. or another method: 2.) You simply use RF chokes at the bottom. In this case the wire can be inside or outside the tower, and it can be secured directly to the tower. Let's see if we can make something so basic and simple so complicated it takes 1000 posts. Since the Ham asking the original question HAD to have the relay 1/4 wl above the open end, the ONLY choice for dielectric when the wire was run INSIDE a closed conductor was air. It had to be an electrical 1/4 wl long, and had to be a very low loss stub since the antenna was voltage fed (high impedance). The suggestion of enclosing the wire in a shield was useless in that application. 73 Tom Article: 226338 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Induced signal? Date: 11 Jul 2006 12:07:35 -0700 Message-ID: <1152644855.491955.105710@p79g2000cwp.googlegroups.com> References: I should have said "the more RF chokes there are, the less current will flow in the center conductor of the case where the wire is inside the shield" by the way. If the RF chokes and wire are inside the shield, it will keep the current off the wire inside the shield. However, where the wire exits the shield, currents can still be induced on it... this is what allows current to flow on the unchoked center conductor, right? So why wouldn't it flow in the other direction. So you need chokes some distance outside the shield to isolate the rest of the wire from the antenna. If you put the wire outside the shield and put chokes at the top and bottom, some distance away from the antenna, then a very large current will be induced on the wire between the chokes compared to the current you get on the wire inside the shield. However, this doesn't immediately translate into more current on the control wire trailing away. It is just saying something about the wire between the top and bottom chokes. What you're trying to do is decouple the control wire going away from the antenna from the antenna. Decoupling the control wire that runs up inside or outside of the antenna isn't very important as long as current doesn't flow on the control wire to the shack. Whether or not inside or outside of the tower/tube helps depends on a lot of factors and should be answered with some sort of calculation... Seems that the various claims are testable... I'll post anything I come up with. Dan Article: 226339 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Voltage feeding a VHF yagi References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> <6cjvn3-s7p.ln1@p400bob.personal.cox.net> <1152218809.770077.3670@s26g2000cwa.googlegroups.com> <1152222378.456155.303810@j8g2000cwa.googlegroups.com> <1152233762.848358.152070@s13g2000cwa.googlegroups.com> <1152578671.148819.275420@b28g2000cwb.googlegroups.com> <1152609823.761832.13220@p79g2000cwp.googlegroups.com> <1152631289.594334.34440@m73g2000cwd.googlegroups.com> <1152643960.102707.230980@35g2000cwc.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 19:15:18 GMT n3ox.dan@gmail.com wrote: > So current flowing on the coax braid = Current flowing from X to B + > Current flowing from Y to B. +--<---A------------X----------------------------- | +--<---B------------Y As you probably know, standing waves in distributed networks modify the conditions. The current "flowing" >from X to B may not be the same amplitude or phase at X and B. The current "flowing" from Y to B may not be the same amplitude or phase at Y and B. This is NOT a DC circuit! So how can any sane person claim that the common mode current at X is identical to the common mode current at B? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226340 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Induced signal? Date: 11 Jul 2006 12:21:06 -0700 Message-ID: <1152645666.609883.321800@h48g2000cwc.googlegroups.com> References: I modeled the original question Cecil asked on r.r.a.a. (current on a coax center conductor of a monopole made of coax) because I was curious and because my wetware simulation for the amount of RF coupled into the end of a piece of coaxial cable wasn't up to the task. I didn't start with the eHam question in mind. I don't know offhand how much the coupling between the center conductor and shield is at the ends of the coax, so I tried some stuff with the only electromagnetic code I have lying around my house. The relay question is not very interesting, it's just an engineering one.. throw good chokes at it. Done. I agree. I wanted to know what the current was in the center conductor of a piece of RG-8 being used as a monopole. The answer to that question is not trivially calculable, though it might be trivial in the sense of being trivia... who cares? I did. Dan Article: 226341 of rec.radio.amateur.antenna From: "David" References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> <1152609735.071204.264590@m79g2000cwm.googlegroups.com> Subject: Re: Quarterwave vertical with radials Date: Tue, 11 Jul 2006 20:14:16 +0100 Message-ID: <34ydnZdtyundZy7ZnZ2dnUVZ8qKdnZ2d@bt.com> One of the earlier postings suggested that the quarterwave vertical antenna with radials was elementary and easy to understand. I have never found this antenna easy to understand. RF experts on this newsgroup cannot agree on whether i) the radials reflect the wave or ii) the field from the radials cancels out. The standard academic books show that the principle behind the vertical ground plane antenna is that the vertical radiating element emits the wave, and is reflected by the ground plane. You can view a conductor as having current pushed through it by a RF source, or the current can be induced in the conductor by the wave. This is a boundary condition in Maxwell's equations, referred to in theory of transmission lines and guided waves. You can view the radials as reflecting the wave and having current induced in them, or they can have current pushed through them by the RF source. This is probably the same thing, due to the arrangement of all antenna parts forming the antenna impedance. In image theory, the impedance comes from both the self impedance and the mutual impedance. It appears that a single counterpoise wire is connected to the RF ground side to provide a conductor for that side and be a form of dipole. If a proper RF ground is not provided, the result may be RF in the shack e.g. the RF tries to return via mains wiring. Does connecting several wires make the RF ground side less live i.e. occupying a larger area to be more of a reflector and thus dissipative? If a RF ground is live, it can be dangerous to touch it. Do you increase the area of RF ground to make it less dangerous to touch e.g. radials under a carpet when relatives and pets are about? >The theory behind the quarterwave vertical is the monopole above a ground >plane, where the ground plane reflects the wave emitted by the vertical. >The monopole is explained using image theory. In practice, the ground plane is >replaced by radials. Do the radials reflect the wave then? >The reflecting element on a Yagi manages to reflect most of the wave. The >reflecting element on a Yagi is a parasitic element that has an impedance >to cause the wave emitted by the driven element to flow in a particular >direction. A Yagi normally has only one reflector. Although the reflector >is in the near field of the Yagi, can a comparison be made with the radials of >a quarterwave vertical antenna? The reflector on a Yagi is usually a thin >tube with lots of air (gap) around it. Even though it occupies a small >area, it still manages to reflect most of the wave. Yagi has a Front to Back >ratio in dB. >Radials can be tuned. Some antennas have loading coils in the radials. > >Antenna theory is often about wires and metallic items reflecting waves, >and the phase of the reflected wave. The phase of the reflected wave can be >constructive or destructive, affecting the impedance of the antenna. If an >antenna is mounted too close to the ground, the reflected wave cancels out >the emitted wave. >Because a ground plane reflects the wave, the impedance of an antenna can >vary with height. >Parastic elements on a Yagi have a mutual impedance to each other. Would >you regard the radials on a quarterwave vertical as having a mutual impedance? >The radials increase the conductivity below the radiating element, >decreasing ground losses. The radials are regarded as a finite or imperfect >ground plane. >References: >"Antenna Theory and Design" by Warren Stutzman and Gary Thiele. pages 66 to >68. Practical monopole with radial wires to simulate a ground plane. >"Antenna Engineering Handbook" by Richard C. Johnson. Radials suppress >currents from flowing on outside of coax. p 28. If the ground is imperfect, >the perfect reflected image is mutiplied by a complex ground reflection >coefficient. The ground has a mutual impedance. >"Antenna Theory" by Professor Constantine Balanis. Second Edition p 165. A >ground plane formed by a perfect conductor completely reflects the wave. If >the ground is finite i.e. not as conductive, it still reflects the wave but >not as well. The conductivity determines the quality of the reflection. Article: 226342 of rec.radio.amateur.antenna From: Ben Jackson Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 14:22:51 -0500 On 2006-07-11, w0zv@yahoo.com wrote: > > Unfortunately K6STI no longer markets his software to hams (due to > software piracy issues). Hopefully you can find someone with a copy > who can optimize your initial results. Careful, you're pegging my irony meter. -- Ben Jackson AD7GD http://www.ben.com/ Article: 226343 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Voltage feeding a VHF yagi Date: 11 Jul 2006 12:25:52 -0700 Message-ID: <1152645952.257578.20580@h48g2000cwc.googlegroups.com> References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> We're talking about the instantaneous common mode current of the real system. That's the current actually flowing in the same direction in both legs of the stub. Article: 226344 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Induced signal? References: <1152607665.959599.175290@s13g2000cwa.googlegroups.com> <1152629374.119641.242380@s13g2000cwa.googlegroups.com> <1152631059.662209.308680@35g2000cwc.googlegroups.com> <1152644044.457865.278650@75g2000cwc.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 19:31:53 GMT w8ji@akorn.net wrote: > You put great faith in passing you Mensa exam. This member of MENSA is having difficulty in parsing your statement. What does, "you Mensa exam", actually mean? Does the pronoun, "you", address the Mensa exam? Wouldn't it be better to address the Mensa exam as an "it" rather than as a person? Your numerous deviations from the accepted laws of physics and accepted English language construction have me confused. > With that in mind, what possible difference does the shield make once > the inner conductor is bypassed and choked at each end? What I said is that, contrary to your strange assertions, is that the RF chokes and RF bypass capacitors block the stub function upon which your entire argument rests. The result of my suggestion is *NOT* a stub function as you have so stubbornly insisted. So I ask you once again: Please prove that a stub with two RF chokes in the conductive path is actually functional as a stub. If you cannot, your entire argument falls apart. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226345 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Induced signal? References: <1152607665.959599.175290@s13g2000cwa.googlegroups.com> <1152629374.119641.242380@s13g2000cwa.googlegroups.com> <1152642814.362640.247960@p79g2000cwp.googlegroups.com> <1152644696.098566.325300@m79g2000cwm.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 19:33:45 GMT w8ji@akorn.net wrote: > The suggestion of enclosing the wire in a shield was useless in that > application. I have done such many times in my 55 years of being a ham. It is NOT useless. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226346 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Induced signal? References: <1152607665.959599.175290@s13g2000cwa.googlegroups.com> <1152629374.119641.242380@s13g2000cwa.googlegroups.com> <1152642814.362640.247960@p79g2000cwp.googlegroups.com> <1152644855.491955.105710@p79g2000cwp.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 19:37:25 GMT n3ox.dan@gmail.com wrote: > If the RF chokes and wire are inside the shield, it will keep the > current off the wire inside the shield. I hope W8JI is reading this. He insists that it will still function as a stub and such an approach is "useless". > However, where the wire exits the shield, currents can still be induced > on it... this is what allows current to flow on the unchoked center > conductor, right? So why wouldn't it flow in the other direction. > > So you need chokes some distance outside the shield to isolate the rest > of the wire from the antenna. Just outside the shield is a relay with an RF bypass cap across its coil. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226347 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Induced signal? Date: 11 Jul 2006 12:41:56 -0700 Message-ID: <1152646916.584677.207180@75g2000cwc.googlegroups.com> References: Cecil Moore wrote: > n3ox.dan@gmail.com wrote: > > If the RF chokes and wire are inside the shield, it will keep the > > current off the wire inside the shield. > > I hope W8JI is reading this. He insists that it will still > function as a stub and such an approach is "useless". > > > However, where the wire exits the shield, currents can still be induced > > on it... this is what allows current to flow on the unchoked center > > conductor, right? So why wouldn't it flow in the other direction. > > > > So you need chokes some distance outside the shield to isolate the rest > > of the wire from the antenna. > > Just outside the shield is a relay with an RF bypass cap > across its coil. > -- > 73, Cecil http://www.qsl.net/w5dxp Turn in your mensa membership card Cecil. You flunked basic grade-K problem solving logic. :-) Article: 226348 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Induced signal? References: <1152607665.959599.175290@s13g2000cwa.googlegroups.com> <1152629374.119641.242380@s13g2000cwa.googlegroups.com> <1152642814.362640.247960@p79g2000cwp.googlegroups.com> <1152644696.098566.325300@m79g2000cwm.googlegroups.com> <1152645666.609883.321800@h48g2000cwc.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 19:42:07 GMT n3ox.dan@gmail.com wrote: > I wanted to know what the current was in the center conductor of a > piece of RG-8 being used as a monopole. The answer to that question is > not trivially calculable, though it might be trivial in the sense of > being trivia... who cares? I did. I have used that same circuit to switch a top hat in and out. How much RF power did I lose by taking that route? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226349 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Voltage feeding a VHF yagi Date: 11 Jul 2006 12:46:11 -0700 Message-ID: <1152647171.449884.309980@p79g2000cwp.googlegroups.com> References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> n3ox.dan@gmail.com wrote: > We're talking about the instantaneous common mode current of the real > system. That's the current actually flowing in the same direction in > both legs of the stub. Hi Dan, Cecil now has to sign his Mensa membership card over to you. You get the point and totally understand the problem. He doesn't. 73 Tom Article: 226350 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Voltage feeding a VHF yagi References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> <6cjvn3-s7p.ln1@p400bob.personal.cox.net> <1152218809.770077.3670@s26g2000cwa.googlegroups.com> <1152222378.456155.303810@j8g2000cwa.googlegroups.com> <1152233762.848358.152070@s13g2000cwa.googlegroups.com> <1152578671.148819.275420@b28g2000cwb.googlegroups.com> <1152609823.761832.13220@p79g2000cwp.googlegroups.com> <1152631289.594334.34440@m73g2000cwd.googlegroups.com> <1152643960.102707.230980@35g2000cwc.googlegroups.com> <1152645952.257578.20580@h48g2000cwc.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 19:49:41 GMT n3ox.dan@gmail.com wrote: > We're talking about the instantaneous common mode current of the real > system. That's the current actually flowing in the same direction in > both legs of the stub. But standing waves of common mode current can and probably do exist. The amplitude of the common mode current varies depending upon its location in the distributed network. At a common mode standing wave node, the common mode current may measure zero. 1/4WL away, it may measure an appreciable magnitude. I have measured such on my own transmission lines. I suspect a dead short forces a common mode standing wave node. What else could possibly happen? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226351 of rec.radio.amateur.antenna From: "Reg Edwards" References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> Subject: Re: Antenna optimization Date: Tue, 11 Jul 2006 20:46:56 +0100 Message-ID: "JC" wrote > Thanks for help, I think I wrongly explained my problem, here is the > question: > 1/ I design an antenna, for instance a 3 el 20m beam. > 2/ I enter into EZNEC wires dimensions, spacing, height, source..... > 3/ EZNEC calculates gain, F/B, SWR....and results are acceptable. > 4/ Now let's suppose my objectives are max F/B as I have a QRM source > opposed to my favourite transmitting direction and SWR< 1.5 on a given > frequency range as my transceiver is very SWR sensitive and I can't use an > antenna tuner. > I accept changing wire lengths and spacing but not boom length. > Is there a way to have EZNEC, or another software, doing automatic > iterations until it reaches the best F/B-SWR compromise ? > ---------------------------------------------------------------------- -------------- Let us see what would be involved if you had EZNEC and had to do everything else yourself the hard way. You already have a crude, satisfactory design for 3 elements, wire lengths, wire diameters, spacing, height, etc. Only the boom length and presumably wire diameters and height are fixed and you wish to optimise everything else for maximum F/B ratio and minimum SWR. Everything else comprises : 3 lengths and 1 spacing. This makes a total of 4 independent variables. You now vary the first variable over a range of say 4 increments, keeping all the other variables constant and keeping a record of the 4 results of F/B ratio and SWR You then vary the second variable over a range of 4 increments, keeping all the other variables constant and keeping a record of the results. You continue to do this until you have done all possible combinations of the 4 variables. You will have a 4-dimension array of results of F/B ratio and SWR, making a total of 512 observations. Now search the observations until you can find the maximum of F/B ratio combined with minimum of SWR If it looks as though the minimum SWR or the maximum F/B ratio lies outside the 4-dimensional array then shift the variables in an appropriate direction and repeat the whole procedure until a max and min are found. The trouble with modelling programs is you have to enter element lengths and spacing via the keyboard. It would be nice to have a program to do it for you. I am unfamiliar with the situation. Such a program might exist - one which outputs F/B ratio and SWR. ---- Reg. Article: 226352 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Quarterwave vertical with radials Date: 11 Jul 2006 12:52:10 -0700 Message-ID: <1152647530.313784.53460@m73g2000cwd.googlegroups.com> References: Cecil Moore wrote: plane of the radials. > > Just ran that test. There was 0.02 dB difference at +45 and -45. Run the test again more carefully. You are looking at something wrong. Perhaps you didn't look at the entire azimuth plot at 45 degrees elevation. There is a large skew with a 1/4 wl vertical over two 1/4 wl radials, and it gets worse at higher elevation numbers. Article: 226353 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Voltage feeding a VHF yagi References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> <6cjvn3-s7p.ln1@p400bob.personal.cox.net> <1152218809.770077.3670@s26g2000cwa.googlegroups.com> <1152222378.456155.303810@j8g2000cwa.googlegroups.com> <1152233762.848358.152070@s13g2000cwa.googlegroups.com> <1152578671.148819.275420@b28g2000cwb.googlegroups.com> <1152609823.761832.13220@p79g2000cwp.googlegroups.com> <1152631289.594334.34440@m73g2000cwd.googlegroups.com> <1152643960.102707.230980@35g2000cwc.googlegroups.com> <1152645952.257578.20580@h48g2000cwc.googlegroups.com> <1152647171.449884.309980@p79g2000cwp.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 19:54:58 GMT w8ji@akorn.net wrote: > n3ox.dan@gmail.com wrote: >> We're talking about the instantaneous common mode current of the real >> system. That's the current actually flowing in the same direction in >> both legs of the stub. > > Cecil now has to sign his Mensa membership card over to you. > You get the point and totally understand the problem. He doesn't. Seems that neither one of you guys realize that common mode current standing waves usually exist so the standing wave common mode current amplitude is NOT constant from one point to another in a distributed network. The lumped constant model strikes (out) once again. When are you guys going to realize that RF is NOT DC? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226354 of rec.radio.amateur.antenna From: "K7ITM" Subject: Re: Antenna optimization Date: 11 Jul 2006 13:00:40 -0700 Message-ID: <1152648040.853122.39360@s13g2000cwa.googlegroups.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> As mentioned in another posting, YO (Yagi Optimizer) would be a good bet. Strange that piracy caused the author to quit offering it completely; seems like any sales are better than none, and not selling a program only makes piracy more likely, not less. But check out the EZNEC co-pilot program from Dan Maguire, AC6LA, at http://www.ac6la.com/. That page lists several of his offerings; it's MultiNEC that you'll be most interested in. Though it may not completely automate the optimization, it should make the process much easier and faster for you. Cheers, Tom JC wrote: > Thanks for help, I think I wrongly explained my problem, here is the > question: > 1/ I design an antenna, for instance a 3 el 20m beam. > 2/ I enter into EZNEC wires dimensions, spacing, height, source..... > 3/ EZNEC calculates gain, F/B, SWR....and results are acceptable. > 4/ Now let's suppose my objectives are max F/B as I have a QRM source > opposed to my favourite transmitting direction and SWR< 1.5 on a given > frequency range as my transceiver is very SWR sensitive and I can't use an > antenna tuner. > I accept changing wire lengths and spacing but not boom length. > Is there a way to have EZNEC, or another software, doing automatic > iterations until it reaches the best F/B-SWR compromise ? > > JC - F8ND > > > "Reg Edwards" a =E9crit dans le message de > news: RtGdnYQxPcYGXS7ZnZ2dnUVZ8qGdnZ2d@bt.com... > > > > "JC" wrote in message > > news:44b3afc1$0$990$ba4acef3@news.orange.fr... > >> Is there a software which can design an antenna (like EZNEC or > > similar ) > >> then allows to automatically optimize its dimensions according to > > given > >> requirements: max gain, F/B, min swr... and accepted dimensional > > parameters > >> changes: boom length, spacing.... > >> JC > > ---------------------------------------------------------------------- > > ------- > > Dear JC, > > > > You don't need software. What you describe is non-existent anyway. > > What you want is a long experienced antenna designer who can be > > permanently engaged on your behalf. There are very few of such > > creatures about. > > > > You will have to be numerically quite specific about particular > > problems. And even then you will get solutions which, with luck, are > > probably only in the right ball-park. > > > > On the other hand, ball-park solutions are perfectly satisfactory. In > > the nature of events, no-one has ever solved an antenna problem which > > is other than in a ball-park. Fortunately, antennas work quite well > > even when in the wrong ball-park. > > > > Download a free copy of EZNEC and in a few months time you may have > > solved your first complicated, specific problem. As time goes on, you > > will become more adept and there will be no need to engage a long > > experienced antenna designer. You will have become one youself and > > can offer your services for hire. > > > > If you have a specific problem you may, if you are lucky, find a > > computer program written by someone who has already solved it. But its > > highly unlikely to be exactly the same problem. It will be in a > > somewhat different ball-park. > > > > Optimisation is out! You will have to contend with whatever you can > > get your hands on. What's been done before. Take it or leave it! > > ---- > > Reg. > > > > Article: 226355 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> <1152609735.071204.264590@m79g2000cwm.googlegroups.com> <1152647530.313784.53460@m73g2000cwd.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 20:02:47 GMT w8ji@akorn.net wrote: > There is a large skew with a 1/4 wl vertical over two 1/4 wl radials, > and it gets worse at higher elevation numbers. Who said anything about two radials? I am reporting the standard model with four radials. I was away >from my computer for four days over the holidays and may have missed the two radial discussion, if there was one. The radial radiation cancellation that I earlier described was based on four radials, certainly not on two. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226356 of rec.radio.amateur.antenna From: "K7ITM" Subject: Re: Antenna optimization Date: 11 Jul 2006 13:03:56 -0700 Message-ID: <1152648236.915225.224660@h48g2000cwc.googlegroups.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> As I just posted in another followup, MultiNEC (add-on for EZNec and other NEC programs) takes care of just this sort of thing for you, and takes much of the tedium out of the process. As an Excel spreadsheet, it does require that you have Excel on the computer you're using. Cheers, Tom Reg Edwards wrote: > "JC" wrote > > Thanks for help, I think I wrongly explained my problem, here is the > > question: > > 1/ I design an antenna, for instance a 3 el 20m beam. > > 2/ I enter into EZNEC wires dimensions, spacing, height, source..... > > 3/ EZNEC calculates gain, F/B, SWR....and results are acceptable. > > 4/ Now let's suppose my objectives are max F/B as I have a QRM > source > > opposed to my favourite transmitting direction and SWR< 1.5 on a > given > > frequency range as my transceiver is very SWR sensitive and I can't > use an > > antenna tuner. > > I accept changing wire lengths and spacing but not boom length. > > Is there a way to have EZNEC, or another software, doing automatic > > iterations until it reaches the best F/B-SWR compromise ? > > > ---------------------------------------------------------------------- > -------------- > > Let us see what would be involved if you had EZNEC and had to do > everything else yourself the hard way. You already have a crude, > satisfactory design for 3 elements, wire lengths, wire diameters, > spacing, height, etc. > > Only the boom length and presumably wire diameters and height are > fixed and you wish to optimise everything else for maximum F/B ratio > and minimum SWR. > > Everything else comprises : 3 lengths and 1 spacing. This makes a > total of 4 independent variables. > > You now vary the first variable over a range of say 4 increments, > keeping all the other variables constant and keeping a record of the 4 > results of F/B ratio and SWR > > You then vary the second variable over a range of 4 increments, > keeping all the other variables constant and keeping a record of the > results. > > You continue to do this until you have done all possible combinations > of the 4 variables. You will have a 4-dimension array of results of > F/B ratio and SWR, making a total of 512 observations. > > Now search the observations until you can find the maximum of F/B > ratio combined with minimum of SWR > > If it looks as though the minimum SWR or the maximum F/B ratio lies > outside the 4-dimensional array then shift the variables in an > appropriate direction and repeat the whole procedure until a max and > min are found. > > The trouble with modelling programs is you have to enter element > lengths and spacing via the keyboard. It would be nice to have a > program to do it for you. I am unfamiliar with the situation. Such a > program might exist - one which outputs F/B ratio and SWR. > ---- > Reg. Article: 226357 of rec.radio.amateur.antenna From: Brian Howie Subject: Re: Antenna optimization Date: Tue, 11 Jul 2006 21:05:18 +0100 Message-ID: References: <44b3afc1$0$990$ba4acef3@news.orange.fr> In message <44b3d3d0$0$819$ba4acef3@news.orange.fr>, JC writes >Thanks for help, I think I wrongly explained my problem, here is the >question: >1/ I design an antenna, for instance a 3 el 20m beam. >2/ I enter into EZNEC wires dimensions, spacing, height, source..... >3/ EZNEC calculates gain, F/B, SWR....and results are acceptable. >4/ Now let's suppose my objectives are max F/B as I have a QRM source >opposed to my favourite transmitting direction and SWR< 1.5 on a given >frequency range as my transceiver is very SWR sensitive and I can't use an >antenna tuner. >I accept changing wire lengths and spacing but not boom length. >Is there a way to have EZNEC, or another software, doing automatic >iterations until it reaches the best F/B-SWR compromise ? MMANA does what you want and it's free. http://mmhamsoft.amateur-radio.ca/ and I see there's a new release out. Read this too. http://g7rau.demon.co.uk/sm5bsz/ Brian GM4DIJ -- Brian Howie Article: 226358 of rec.radio.amateur.antenna From: Ron Subject: Re: Antenna optimization Date: 11 Jul 2006 16:37:59 EDT Message-ID: <44B40DB6.502@yahoo.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> I downloaded MMANA but I can't seem to unzip it. What program will unzip it ? I have WinZip 7.0 Thanks Ron WA0KDS Brian Howie wrote: > In message <44b3d3d0$0$819$ba4acef3@news.orange.fr>, JC > writes > >> Thanks for help, I think I wrongly explained my problem, here is the >> question: >> 1/ I design an antenna, for instance a 3 el 20m beam. >> 2/ I enter into EZNEC wires dimensions, spacing, height, source..... >> 3/ EZNEC calculates gain, F/B, SWR....and results are acceptable. >> 4/ Now let's suppose my objectives are max F/B as I have a QRM source >> opposed to my favourite transmitting direction and SWR< 1.5 on a given >> frequency range as my transceiver is very SWR sensitive and I can't >> use an >> antenna tuner. >> I accept changing wire lengths and spacing but not boom length. >> Is there a way to have EZNEC, or another software, doing automatic >> iterations until it reaches the best F/B-SWR compromise ? > > > > MMANA does what you want and it's free. > > http://mmhamsoft.amateur-radio.ca/ and I see there's a new release out. > > Read this too. http://g7rau.demon.co.uk/sm5bsz/ > > Brian GM4DIJ Article: 226359 of rec.radio.amateur.antenna From: w0zv@yahoo.com Subject: Re: Antenna optimization Date: 11 Jul 2006 13:45:49 -0700 Message-ID: <1152650749.420397.51760@m73g2000cwd.googlegroups.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> Ben AD7GD wrote: > On 2006-07-11, w0zv@yahoo.com wrote: > > > > Unfortunately K6STI no longer markets his software to hams (due to > > software piracy issues). Hopefully you can find someone with a copy > > who can optimize your initial results. > > Careful, you're pegging my irony meter. Why? The documentation says: ************************************************************************ This software is copyrighted. It has been provided to you on the condition that you will not sell, rent, lend, give away, or otherwise transfer the software to others. ************************************************************************ As I read it, there is no problem if I use it to optimize a model for someone else. I'm NOT volunteering to do that however. 73, Bill W4ZV Article: 226360 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Voltage feeding a VHF yagi Date: 11 Jul 2006 14:06:10 -0700 Message-ID: <1152651970.397776.294700@35g2000cwc.googlegroups.com> References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> In the case where the J-pole is isolated (crossbanding HT at the feedpoint?) there's absolutely a node for the common mode current at the short, just like there's a node for the current on a wire at the end where the current can't flow. If you put a feedline on it, though, the standing wave pattern of common mode current changes. The feedline + jpole develops some pattern of standing waves on it. The common mode current is induced on the entire length of coax and stub... The sum of the common mode currents at point B is always as stated before... but the magnitude of ALL THREE of them depends on the details of the coax, whether or not there is a choke balun on it, the length and boundary condition on the other end of the coax. That is to say the common mode impedance at the top of the stub where the halfwave is connected depends on the details of the feedline. Stub vs. Stub + Coax: different common mode standing wave pattern, different common mode impedance at the top of the stub, different magnitude of current induced on the stub+coax than on the plain stub... Dan Article: 226361 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Voltage feeding a VHF yagi References: <1152164230.300210.322520@m79g2000cwm.googlegroups.com> <6cjvn3-s7p.ln1@p400bob.personal.cox.net> <1152218809.770077.3670@s26g2000cwa.googlegroups.com> <1152222378.456155.303810@j8g2000cwa.googlegroups.com> <1152233762.848358.152070@s13g2000cwa.googlegroups.com> <1152578671.148819.275420@b28g2000cwb.googlegroups.com> <1152609823.761832.13220@p79g2000cwp.googlegroups.com> <1152631289.594334.34440@m73g2000cwd.googlegroups.com> <1152643960.102707.230980@35g2000cwc.googlegroups.com> <1152645952.257578.20580@h48g2000cwc.googlegroups.com> <1152651970.397776.294700@35g2000cwc.googlegroups.com> Message-ID: Date: Tue, 11 Jul 2006 21:51:04 GMT n3ox.dan@gmail.com wrote: > If you put a feedline on it, though, the standing wave pattern of > common mode current changes. +--<---A------------X----------------------------- | +--<---B------------Y On my diagram, the coax is always connected at A and B so *nothing has changed*. I just don't see any reason for the common mode current at 'X' to be exactly the same as the common mode current at 'B'. Do you? -- 73, Cecil http://www.qsl.net/w5dxp Article: 226362 of rec.radio.amateur.antenna From: Ron Subject: Re: Antenna optimization HELP Date: 11 Jul 2006 17:47:48 EDT Message-ID: References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <44B40DB6.502@yahoo.com> Ron wrote: I downloaded MMANA but I can't seem to unzip it. What program will unzip it ? I have WinZip 7.0 Thanks Ron WA0KDS Article: 226363 of rec.radio.amateur.antenna From: Ron Subject: Re: Antenna optimization HELP Date: 11 Jul 2006 17:48:51 EDT Message-ID: References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <44B40DB6.502@yahoo.com> Ron wrote: I downloaded MMANA but I can't seem to unzip it. What program will unzip it ? I have WinZip 7.0 Thanks Ron WA0KDS Article: 226364 of rec.radio.amateur.antenna From: "K7ITM" Subject: Re: Antenna optimization Date: 11 Jul 2006 14:58:36 -0700 Message-ID: <1152655116.465003.133590@m73g2000cwd.googlegroups.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> FWIW, FilZip unzipped it fine: one file, MMANGAL_Setup.exe. It's possible that the zip file became corrupted when you downloaded it, too. Cheers, Tom Ron wrote: > I downloaded MMANA but I can't seem to unzip it. What program will > unzip it ? I have WinZip 7.0 > > Thanks > Ron WA0KDS > > > Brian Howie wrote: > > In message <44b3d3d0$0$819$ba4acef3@news.orange.fr>, JC > > writes > > > >> Thanks for help, I think I wrongly explained my problem, here is the > >> question: > >> 1/ I design an antenna, for instance a 3 el 20m beam. > >> 2/ I enter into EZNEC wires dimensions, spacing, height, source..... > >> 3/ EZNEC calculates gain, F/B, SWR....and results are acceptable. > >> 4/ Now let's suppose my objectives are max F/B as I have a QRM source > >> opposed to my favourite transmitting direction and SWR< 1.5 on a given > >> frequency range as my transceiver is very SWR sensitive and I can't > >> use an > >> antenna tuner. > >> I accept changing wire lengths and spacing but not boom length. > >> Is there a way to have EZNEC, or another software, doing automatic > >> iterations until it reaches the best F/B-SWR compromise ? > > > > > > > > MMANA does what you want and it's free. > > > > http://mmhamsoft.amateur-radio.ca/ and I see there's a new release out. > > > > Read this too. http://g7rau.demon.co.uk/sm5bsz/ > > > > Brian GM4DIJ Article: 226365 of rec.radio.amateur.antenna From: Iain Kelly Subject: Re: New Swiss antenna system... Date: Tue, 11 Jul 2006 23:29:01 +0100 Message-ID: References: <1152588973.511463.222930@p79g2000cwp.googlegroups.com> <12b7qb5ohcdhk5b@corp.supernews.com> Roy Lewallen wrote: > One of the basic principles of the cellular telephone system is that the > same parts of the spectrum can be used by many phones at once. This is > possible only because each cell covers only a limited area. High spots > which cover huge areas are pretty common -- just look at typical > repeater or TV/FM broadcasting locations. But you won't find cell phone > installations there except in very sparsely populated areas, and for > very good reason -- there simply isn't anywhere near enough spectrum > space available to accommodate all the users within range. > > Figuring out how to cram a couple of orders of magnitude more users into > the same already-packed and efficiently used spectrum must be one of > those "technological hurdles" yet to be overcome. > > But in the meantime, I'm sure Alavi is living quite well off the money > from the naive investors which never seem to be in short supply. > > Roy Lewallen, W7EL Whilst the above comments are very well made I must say that there are some good ideas with this whole HAP thing. A lot of my lecturers and professors are involved with a big chunk of the research into this venture, and for high speed broadband data access the idea is good. The points made about cellular systems are true, but it is my understanding that in densely populated areas there would be more HAPs up in the air, each could have multiple cells potentially... Having said that I do get the impression from some research seminars I've been to on the subject, that there is still a lot of work to be done before the proposal can be realised to it's full potential, but I do think the principle is sound. -- 73, Iain M0PCB/P Article: 226366 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Voltage feeding a VHF yagi Date: 11 Jul 2006 15:33:32 -0700 Message-ID: <1152657212.158640.43920@h48g2000cwc.googlegroups.com> References: <1152218809.770077.3670@s26g2000cwa.googlegroups.com> Cecil Moore wrote: > n3ox.dan@gmail.com wrote: > > If you put a feedline on it, though, the standing wave pattern of > > common mode current changes. > > +--<---A------------X----------------------------- > | > +--<---B------------Y > > > On my diagram, the coax is always connected > at A and B so *nothing has changed*. I just don't see > any reason for the common mode current at 'X' to be > exactly the same as the common mode current at 'B'. > Do you? No, but no one said that except you. I would guess this is another typical diversion by you, where you try to change what others say when you put your foot into doo doo. What I said was: 1.) Current was the SAME at both sides of X. 2.) Because Y is NOT terminated, the CM current unblances that line. 3.) The length of the line from the short to X transforms this CM current t a new value. 4.) That value can be considerably higher than the CM current at X. 5.) When people tap a coaxial line up on the stub, they now create additional CM problems besides the initial one. The new problem is the initial imbalance in the stub can be aggrivated by imbalance where the coax transitions to the stub. The whole system is a mess. The ONLY way it models good is if: 1.) The center point of the stub is floated from ground. 2.) The coax is decoupled through a high common mode impedance on its shield at the connection point t the stub When people through a source out on that stub, it looks like coax through a perfect balun. At the same time they float the stub shortyed end, and that makes the stub DECREASE CM current along its length. In the REAL world the center point of the stub is almost always grounded. In the REAL world the coax is never perfectly decoupled. This is why all the models of J-poles are generally wrong. Only models that include the shield connection and the grounding or connectiong of the shorted end of the J, when properly done, are correct. Cecil, you really do need to think about things like this much more careful than you do before telling others they are using DC models. It just makes it look like you can't think clearly about very simple basic systems when you miss the points I listed above. 73 Tom Article: 226367 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Induced signal? Date: 11 Jul 2006 15:38:03 -0700 Message-ID: <1152657483.200112.122940@35g2000cwc.googlegroups.com> References: Cecil Moore wrote: > n3ox.dan@gmail.com wrote: > > I wanted to know what the current was in the center conductor of a > > piece of RG-8 being used as a monopole. The answer to that question is > > not trivially calculable, though it might be trivial in the sense of > > being trivia... who cares? I did. > > I have used that same circuit to switch a top hat > in and out. How much RF power did I lose by taking > that route? That is NOTHING like the problem the ZL on eHam had. Article: 226368 of rec.radio.amateur.antenna From: "Reg Edwards" References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <44B40DB6.502@yahoo.com> <1152655116.465003.133590@m73g2000cwd.googlegroups.com> Subject: Re: Antenna optimization Date: Tue, 11 Jul 2006 23:41:43 +0100 Message-ID: Why on Earth anybody zips up software these days I can't imagine. Article: 226369 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: Optibeam & LP antennas Date: Tue, 11 Jul 2006 19:13:24 -0400 Message-ID: <12b8c1maig5uhf2@corp.supernews.com> References: Dear Ron: Go for a good, well made, USA LPDA. As an example: the Tennadyne T10 (www.tennadyne.com) compared to the OB9-5 has a longer boom, uses more material, has a lower cost, has no custom/duty issues, and a long track record. The gain figures posted by Tennadyne are reasonable and well labeled. For MARS like service, an LPDA can not be matched. If you decide on a LPDA, contact me off-line and I can provide some simple ideas on simplifying installation. 73, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Ron Walters" wrote in message news:mpZqg.52963$7G2.46905@tornado.tampabay.rr.com... > Dave wrote: > > I looked at their web site and did not see a 'Log Periodic'. > > > > Their antennas seem to be Yagi based. A L-P is a driven array, not > > parasitic, and broad banded so that the VSWR never exceeds a max value, > > typically 1.7:1, ANYWHERE in the spectrum from 14 to 30 MHz in the > > bandwidth you mentioned. > > > > Do you have a model number? > > > > /s/ DD W1MCE > > > > Ron Walters wrote: > > > >> Would appreciate comments relative to the Optibeam Log Periodic > >> 14-30MHz antennas, I am also considering the SteppIR antenna but I am > >> concerned with the mechanical and electric potential problems with > >> that antenna. > >> Getting on in age and tower climbing is s chore for me. Any > >> suggestions or comments? > >> > >> Ron W4LDE > > > > > Dave, > > Thanks for your comments, the Optibeam antenna model I was looking at is > the OB9-5 broadband antenna. The spec's seem good, low wind load and > looks like it would survive in the sunny south were we do get those darn > Hurricanes. I live in Central Floria. My TA-33 has gone through 4 > storms with some very gusts of over 100 MPH and still preforms without > a change from the day I put it up back in 1988, almost 18 years, thats > service. > > The other antennas I am looking at is the Summer XP504-6 LP that is > rated 13-54 MHz and the Cushcraft ASL2010. The gain figures look higher > than the Optibeam but I guess that its all relative. > > Theres no doubt that the SteppIR 3- element is a great beam, but from > what I have read over the past few years since it first hit the market > is that there has been problems, both mechanical and electrical. That > fact frightens me, here I live in the lighting capital of the world and > also from time to time need to adjust to Hurricanes, if I didn't love > golf also I probably live future up north in SC or NC but thats not the > issue. In a few years my days climbing towers will get very difficult > and probable not to smart. > > After looking at the choices one has in a multi-band antenna for 20-6 > meters I have come to realize that the LP maybe my alternative for a > long term survivable antenna. You were right after looking at the > Optibeam it is not a LP like the Summer or Cushcraft. > > What bothers me about the current LP offering is I do not see many > opinions or comments relative to this type of antenna, guess everyone > likes the new SteppIR and before its over I may re-think my choices. > > Again thanks for the comment > > 73 - Ron W4LDE Article: 226370 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: EZNEC Question Date: Tue, 11 Jul 2006 16:26:07 -0700 Message-ID: <12b8csh91df3f75@corp.supernews.com> References: <12b0snu32ufisd2@corp.supernews.com> <44B11F25.1010108@fuse.net> J. B. Wood wrote: > > Hello, and as long as kudos are being handed out I thought I'd jump in and > say that while programs like EZNEC add some user-friendliness and > graphical capability they rely on the NEC (usually NEC-2) engine. For > NEC-1, NEC-2 and NEC-4 Gerald Burke and others at the Lawrence Livermore > Lab deserve a lion's share of credit for drafting user documentation, > correcting bugs and enhancing code that was originally done in the early > '70s by MBAssociates for the U.S. Naval Research Laboratory (NRL). Just a > bit of NEC history. Sincerely, and 73s from N4GGO, > > John Wood (Code 5550) e-mail: wood@itd.nrl.navy.mil > Naval Research Laboratory > 4555 Overlook Avenue, SW > Washington, DC 20375-5337 I absolutely and enthusiastically second that. My contribution has been almost solely an interface (although at around 60,000 lines of code it's not completely trivial). The underlying code was the work of a number of very savvy people, including Dr. Burke who still supports it as time permits. EZNEC would not have been possible without those people's extensive, painstaking, and superbly documented work. Many other people have given a good deal of time in aiding with the development of EZNEC. I encourage all EZNEC users to read the "Acknowledgements" section in the "Introduction" chapter of the EZNEC manual. Roy Lewallen, W7EL Article: 226371 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1152298653.803900.283720@s13g2000cwa.googlegroups.com> <1152543835.522559.53450@75g2000cwc.googlegroups.com> Subject: Re: Reradiating RF signals from Satellital Modem Date: Wed, 12 Jul 2006 00:25:01 +0100 Message-ID: <_I2dnY1R5aeGqSnZRVnygg@bt.com> If ground loss is very small when ground resistivity is very low (sea water) and is also very small when resistivity is very high (arid deep desert sand) then ground loss must be a maximum at some intermediate value of ground resistivity. Does the ground loss reach its maximum when ground resistivity is around 377 ohms (Conductivity = 2.65 milli-siemens). Now where have I seen 377 before? It's just hard luck if your back yard happens to be about that value. ---- Reg. Article: 226372 of rec.radio.amateur.antenna From: "K7ITM" Subject: Re: Antenna optimization Date: 11 Jul 2006 16:30:31 -0700 Message-ID: <1152660631.395300.16690@b28g2000cwb.googlegroups.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> Reg Edwards wrote: > Why on Earth anybody zips up software these days I can't imagine. I thought you'd have a better imagination than that, Reg. o To reduce the size of the transferred file. o To package a set of files together, e.g. documentation and sample files along with a program, or a set of related programs. o To secure it; it may not be very robust security but would discourage the casual user. For the present example, though, the benefit is marginal at best. Cheers, Tom Article: 226373 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Quarterwave vertical with radials Date: 11 Jul 2006 17:29:53 -0700 Message-ID: <1152664193.502576.106990@s13g2000cwa.googlegroups.com> References: Cecil Moore wrote: > w8ji@akorn.net wrote: > > There is a large skew with a 1/4 wl vertical over two 1/4 wl radials, > > and it gets worse at higher elevation numbers. > > Who said anything about two radials? Actually YOU did. Several times as a matter of fact. > I am reporting > the standard model with four radials. I was away > from my computer for four days over the holidays > and may have missed the two radial discussion, if > there was one. > > The radial radiation cancellation that I earlier > described was based on four radials, certainly > not on two. > -- > 73, Cecil http://www.qsl.net/w5dxp Here is what you said on this very thread: Cecil Moore wrote: > Tom Donaly wrote: > > If you can bring yourself to think in terms of > > current directions and far field superposition of waves, this > > behavior shouldn't be that hard to understand. > > It's pretty easy to understand. Any two radials, > 180 degrees apart and high enough, should theoretically > cancel each other's radiation in the far field. > -- > 73, Cecil http://www.qsl.net/w5dxp Maybe reading one of your own posts will jog your memory a bit. In it we see you VERY CLEARLY stated two radials would cancel each other's radiation. 73 Tom Article: 226374 of rec.radio.amateur.antenna From: "DrDeath" Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers IfNecesssary. Date: Tue, 11 Jul 2006 20:29:33 -0500 Message-ID: <12b8k3ugq5ovgeb@corp.supernews.com> References: <4n6ql.jaf.19.1@news.alt.net> "Don Bowey" wrote in message news:C0D93A5D.39F0B%dbowey@comcast.net... > On 7/11/06 7:57 AM, in article e90e8c$32e$1@news04.infoave.net, "John > Jowdy" > wrote: > >> I can already detect a vast improvement, keep up the good work and good >> luck >> in the contest. >> >> W1AW, Rick Lindquist >> >> >> "Paul Willie Schleck" wrote in message >> news:4n6ql.jaf.19.1@news.alt.net... >>> Warning. I, Paul W Schreck, blowgut of blowguts, and self-appointed >>> moderator, will be monitoring these newsgroups for inappropriate >>> statements, >>> misuse of the groups, cross-posting and foul language and will be saving >>> and >>> archiving your comments for future use. >>> >>> Any future and wanton misuse of my name or callsign or forgeries thereof >>> will be recorded as well. >>> >>> I will not hesitate to contact aeiou.com, wxyz, CBS, NBC, BBC or >>> Altopia, >>> or >>> any other provider to turn you and your cohorts in for punitive action. >>> >>> While these groups are largely unmoderated, I am here to tell you that >>> there >>> is a new Sheriff in town, and the Sheriff is me. >>> >>> >>> >>> You have been warned. Conduct yourself accordingly or risk losing your >>> ISP. >>> >>> >>> >>> Paul W. Schreck, Self Appointed Moderator Supreme, New Sheriff. >>> >>> Hissyfits@novia.nel >>> >>> www.blowguts.com >>> >>> >>> >>> >>> >>> >> >> > > Hey Paul, > > Kiss mine, you officious ass. Go moderate a CB channel. > > We don't need another know it all ham in the cb group. Article: 226375 of rec.radio.amateur.antenna From: "an_old_friend" Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers IfNecesssary. Date: 11 Jul 2006 18:36:03 -0700 Message-ID: <1152668163.235641.260620@m73g2000cwd.googlegroups.com> References: <4n6ql.jaf.19.1@news.alt.net> DrDeath wrote: > "Don Bowey" wrote in message > news:C0D93A5D.39F0B%dbowey@comcast.net... > > On 7/11/06 7:57 AM, in article e90e8c$32e$1@news04.infoave.net, "John > > Jowdy" > > Kiss mine, you officious ass. Go moderate a CB channel. > > > > > We don't need another know it all ham in the cb group. h e could ertainly teach you some manners and a few other things Article: 226376 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Voltage feeding a VHF yagi References: <1152218809.770077.3670@s26g2000cwa.googlegroups.com> <1152222378.456155.303810@j8g2000cwa.googlegroups.com> <1152233762.848358.152070@s13g2000cwa.googlegroups.com> <1152578671.148819.275420@b28g2000cwb.googlegroups.com> <1152609823.761832.13220@p79g2000cwp.googlegroups.com> <1152631289.594334.34440@m73g2000cwd.googlegroups.com> <1152643960.102707.230980@35g2000cwc.googlegroups.com> <1152645952.257578.20580@h48g2000cwc.googlegroups.com> <1152651970.397776.294700@35g2000cwc.googlegroups.com> <1152657212.158640.43920@h48g2000cwc.googlegroups.com> Message-ID: Date: Wed, 12 Jul 2006 01:46:15 GMT w8ji@akorn.net wrote: > Cecil Moore wrote: >> On my diagram, the coax is always connected >> at A and B so *nothing has changed*. I just don't see >> any reason for the common mode current at 'X' to be >> exactly the same as the common mode current at 'B'. >> Do you? > > No, but no one said that except you. > What I said was: Sorry, that's not what you said. What you said was that there is as much common mode current flowing down the feedline (at point B) as is flowing into the half-wave end-fed section of the antenna (at point X). +--A--------X------------------- | +--B--------Y The half-wave end-fed antenna starts at point X. The feedline is at point B. Here's what you said: w8ji@akorn.net wrote: > 1.) You have a half-wave end-fed antenna. There has to be as much > common mode current leaving the end of that point and flowing down the > feedline as there is flowing out onto the antenna at that point. There > isn't any exception to this rule. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226377 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Induced signal? References: <1152607665.959599.175290@s13g2000cwa.googlegroups.com> <1152629374.119641.242380@s13g2000cwa.googlegroups.com> <1152642814.362640.247960@p79g2000cwp.googlegroups.com> <1152644696.098566.325300@m79g2000cwm.googlegroups.com> <1152645666.609883.321800@h48g2000cwc.googlegroups.com> <1152657483.200112.122940@35g2000cwc.googlegroups.com> Message-ID: <6yYsg.63956$fb2.47802@newssvr27.news.prodigy.net> Date: Wed, 12 Jul 2006 01:48:50 GMT w8ji@akorn.net wrote: > Cecil Moore wrote: >> I have used that same circuit to switch a top hat >> in and out. How much RF power did I lose by taking >> that route? > > That is NOTHING like the problem the ZL on eHam had. Clutching at straws, are we? It's exactly like the ZL problem except the relay is used to switch a top hat instead of a wire. -- 73, Cecil http://www.qsl.net/w5dxp From k6mhek6mhecom> Newsgroups: rec.radio.amateur.antenna Subject: Re: EZNEC Question Date: Tue, 11 Jul 2006 18:52:02 -0700 Message-ID: References: <12b0snu32ufisd2@corp.supernews.com> <44B11F25.1010108@fuse.net> <12b8csh91df3f75@corp.supernews.com> X-Newsreader: Forte Agent 1.93/32.576 English (American) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 41 NNTP-Posting-Host: 68.64.59.124 X-Trace: sv3-4un3vSovM6lXGrAETGWYS2lQVUkay4YLc2qwMZG/ONoUU4/ENRJFT+AdX4H7KHFVJPupDiuzuSUglI4!uM/AwIb5ztvC90hSdRcz1216h7vzTJ7CSDs0JMmfvHNG/9iJVzlE6HQ/JLuwtIaKSjo3vGt/+sRY!0nbKl0kcQngcNZ25DvIA X-Complaints-To: abuse@adelphia.net X-DMCA-Complaints-To: copyright@adelphia.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.32 Path: news.unc.edu!elk.ncren.net!news2.wam.umd.edu!bloom-beacon.mit.edu!newsswitch.lcs.mit.edu!newsfeed.cwix.com!newscon02.news.prodigy.com!newscon06.news.prodigy.com!prodigy.net!border1.nntp.dca.giganews.com!border2.nntp.dca.giganews.com!nntp.giganews.com!local01.nntp.dca.giganews.com!nntp.adelphia.com!news.adelphia.com.POSTED!not-for-mail Xref: news0.isis.unc.edu rec.radio.amateur.antenna:226378 On Tue, 11 Jul 2006 16:26:07 -0700, Roy Lewallen wrote: >J. B. Wood wrote: >> >> Hello, and as long as kudos are being handed out I thought I'd jump in and >> say that while programs like EZNEC add some user-friendliness and >> graphical capability they rely on the NEC (usually NEC-2) engine. For >> NEC-1, NEC-2 and NEC-4 Gerald Burke and others at the Lawrence Livermore >> Lab deserve a lion's share of credit for drafting user documentation, >> correcting bugs and enhancing code that was originally done in the early >> '70s by MBAssociates for the U.S. Naval Research Laboratory (NRL). Just a >> bit of NEC history. Sincerely, and 73s from N4GGO, >> >> John Wood (Code 5550) e-mail: wood@itd.nrl.navy.mil >> Naval Research Laboratory >> 4555 Overlook Avenue, SW >> Washington, DC 20375-5337 > >I absolutely and enthusiastically second that. My contribution has been >almost solely an interface (although at around 60,000 lines of code it's >not completely trivial). The underlying code was the work of a number of >very savvy people, including Dr. Burke who still supports it as time >permits. EZNEC would not have been possible without those people's >extensive, painstaking, and superbly documented work. > >Many other people have given a good deal of time in aiding with the >development of EZNEC. I encourage all EZNEC users to read the >"Acknowledgements" section in the "Introduction" chapter of the EZNEC >manual. > >Roy Lewallen, W7EL Roy fails to mention that he recently discovered a bug in the NEC code which he passed on to Gerald Burke at LLB. I suggest that Roy is also envolved more than just providing an interface for running the NEC engine. Danny, K6MHE Article: 226379 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Quarterwave vertical with radials Date: Tue, 11 Jul 2006 18:50:04 -0700 Message-ID: References: <12b55ges6lfod74@corp.supernews.com> <8q65b2ll3uuhpmeemdsoj9s5tke8mflt63@4ax.com> <-9ydnShC5I44TC7ZnZ2dnUVZ_umdnZ2d@adelphia.com> On Tue, 11 Jul 2006 12:36:18 -0400, John Popelish wrote: >The center line I am referring to is the mirror line of the ground >plane or radial group that allows a monopole to have a field pattern >(both E and H) above that mirror line, that would exist there, if the >antenna was a symmetrical dipole. Without the mirror effect, the >field pattern of the monopole depends on the path the feed line takes >away from the monopole, and any other conductive objects nearby. Hi John, This is still rather obscure. You are not talking about a line, but yet another plane. World of difference there, but I won't dispute semantics further. Simply raise that monopole, complete with radial plane and the center line (as you call it), ABOVE the ground plane. I've already analyzed this elsewhere in conventional jargon, but here it seems Photons offer a different conclusion. Unfortunately you aren't prepared to pursue this as you admit later. The conventional analysis is perfectly capable of dealing with feed lines or by avoiding them altogether. One can certainly conspire to fail and corrupt the analysis, so avoiding distractions and placing the source in the model, at the feedpoint, removes a lot of uncertainty. >Since I am talking about field patterns, it seemed natural to switch >from total radiated watts to field intensities and the photons that >field emits and where those photons head. Photons (as any radiation in this case) are incoherent and radiate in all directions. >While amateurs may ultimately be interested in radiating power in >particular directions, we are discussing the physics of the radiation >process, and photonics is one way to think about that process. I am perfectly content and competent to that goal. >The ultimate radial pattern is a solid disk. Once you understand what >that does to the field pattern, you can start toward a radial wire >layer, and see how, in important ways, like the ability to carry >radial current, it resembles a disk. Then, you can explore how >reducing the number of radials alters the approximation. I don't see a photon in this at all. >> You were going to tie this all together weren't you? > >Probably not, since I am working through the process in my own mind. >I am not the teacher so much as a student trying to learn something >useful. I hope my posts generate more useful discussion from others >than I have gotten from you, so far. I have, with neutral objectivity, posed issues of diffraction. For one, the quarterwave antenna, in close proximity to a quarterwave mirror (those radials), does not present the characteristics of a point source that might render attractive solutions. Further, even a point source ray striking a quarterwave mirror suffers considerably. The long and short of it is that Photons make for an interesting discussion with regards to antennas. Unfortunately, and as you obliquely observe about me writing for myself, it seems I'm the only one willing to carry the topic. 73's Richard Clark, KB7QHC Article: 226380 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 20:53:27 -0500 From: Tom Ring Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers IfNecesssary. References: <4n6ql.jaf.19.1@news.alt.net> <12b8k3ugq5ovgeb@corp.supernews.com> Message-ID: <44b45621$0$1016$39cecf19@news.twtelecom.net> DrDeath wrote: >> >>Kiss mine, you officious ass. Go moderate a CB channel. >> >> > > We don't need another know it all ham in the cb group. > > This whole thing was started by what's called a troll. It was forged, not from the person it purports to be from. Many of the "responses" are also forged, and from the same person or his cohorts. It exists to piss people off, get them riled up, and so the forgers can sit back and laugh at what they have gotten those in the newsgroups, who they consider to be idiots, to post as responses. Tom K0TAR A ham who came from CB a long time ago, ain't a know-it-all, and doesn't care to tell you what to do, since it's your business. Article: 226381 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 20:55:58 -0500 From: Tom Ring Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> <1152609735.071204.264590@m79g2000cwm.googlegroups.com> <1152647530.313784.53460@m73g2000cwd.googlegroups.com> <1152664193.502576.106990@s13g2000cwa.googlegroups.com> Message-ID: <44b456ae$0$1016$39cecf19@news.twtelecom.net> w8ji@akorn.net wrote: > Maybe reading one of your own posts will jog your memory a bit. In it > we see you VERY CLEARLY stated two radials would cancel each other's > radiation. > > 73 Tom > Won't matter, he'll have an explanation for it, and it will be anyone's fault but his. tom K0TAR Article: 226382 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> <1152609735.071204.264590@m79g2000cwm.googlegroups.com> <1152647530.313784.53460@m73g2000cwd.googlegroups.com> <1152664193.502576.106990@s13g2000cwa.googlegroups.com> Message-ID: Date: Wed, 12 Jul 2006 01:58:51 GMT w8ji@akorn.net wrote: > Maybe reading one of your own posts will jog your memory a bit. In it > we see you VERY CLEARLY stated two radials would cancel each other's > radiation. Two radials do indeed cancel each other's radiation to a large extent. But I certainly didn't say there were two and only two radials in the entire system. I missed four days of postings. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226383 of rec.radio.amateur.antenna Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers IfNecesssary. From: Steveo Message-ID: <20060711222038.985$QM@newsreader.com> References: <4n6ql.jaf.19.1@news.alt.net> <12b8k3ugq5ovgeb@corp.supernews.com> <44b45621$0$1016$39cecf19@news.twtelecom.net> Date: 12 Jul 2006 02:16:51 GMT Tom Ring wrote: >> It exists to piss people off > You said it! -- http://NewsReader.Com/ Article: 226384 of rec.radio.amateur.antenna Date: Tue, 11 Jul 2006 19:25:14 -0700 Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers From: Don Bowey Message-ID: References: <4n6ql.jaf.19.1@news.alt.net> <12b8k3ugq5ovgeb@corp.supernews.com> On 7/11/06 6:29 PM, in article 12b8k3ugq5ovgeb@corp.supernews.com, "DrDeath" wrote: > "Don Bowey" wrote in message > news:C0D93A5D.39F0B%dbowey@comcast.net... >> On 7/11/06 7:57 AM, in article e90e8c$32e$1@news04.infoave.net, "John >> Jowdy" >> wrote: >> >>> I can already detect a vast improvement, keep up the good work and good >>> luck >>> in the contest. >>> >>> W1AW, Rick Lindquist >>> >>> >>> "Paul Willie Schleck" wrote in message >>> news:4n6ql.jaf.19.1@news.alt.net... >>>> Warning. I, Paul W Schreck, blowgut of blowguts, and self-appointed >>>> moderator, will be monitoring these newsgroups for inappropriate >>>> statements, >>>> misuse of the groups, cross-posting and foul language and will be saving >>>> and >>>> archiving your comments for future use. >>>> >>>> Any future and wanton misuse of my name or callsign or forgeries thereof >>>> will be recorded as well. >>>> >>>> I will not hesitate to contact aeiou.com, wxyz, CBS, NBC, BBC or >>>> Altopia, >>>> or >>>> any other provider to turn you and your cohorts in for punitive action. >>>> >>>> While these groups are largely unmoderated, I am here to tell you that >>>> there >>>> is a new Sheriff in town, and the Sheriff is me. >>>> >>>> >>>> >>>> You have been warned. Conduct yourself accordingly or risk losing your >>>> ISP. >>>> >>>> >>>> >>>> Paul W. Schreck, Self Appointed Moderator Supreme, New Sheriff. >>>> >>>> Hissyfits@novia.nel >>>> >>>> www.blowguts.com >>>> >>>> >>>> >>>> >>>> >>>> >>> >>> >> >> Hey Paul, >> >> Kiss mine, you officious ass. Go moderate a CB channel. >> >> > We don't need another know it all ham in the cb group. > > Drat! Article: 226385 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Induced signal? Date: Tue, 11 Jul 2006 20:25:44 -0700 Message-ID: References: <1152607665.959599.175290@s13g2000cwa.googlegroups.com> <1152629374.119641.242380@s13g2000cwa.googlegroups.com> <1152642814.362640.247960@p79g2000cwp.googlegroups.com> <1152644696.098566.325300@m79g2000cwm.googlegroups.com> <1152645666.609883.321800@h48g2000cwc.googlegroups.com> On 11 Jul 2006 12:21:06 -0700, "n3ox.dan@gmail.com" wrote: >I wanted to know what the current was in the center conductor of a >piece of RG-8 being used as a monopole. The answer to that question is >not trivially calculable, though it might be trivial in the sense of >being trivia... who cares? I did. > >Dan Hi Dan, All the issues you focus on are quite particular and specific, and perhaps too much so. I find them equally interesting and you ask reasonable questions. Unfortunately, you question above suffers from every problem imaginable for measuring, and any report you get without considerable qualification is probably sheer fancy. It suffers from a version of Heisenberg's problem of disturbing what you attempt to measure, and invalidating everything in the process. Another way of stating this problem, with more practicality, is that you have to put a wire into the coax to add your meter to make the measurement. This then brings that wire's own contribution, which, as you've noted, can raise the stakes considerably. I, too, have played with a variant of your model (I can push the mesh finer and have worked with a 16 sided coax model). However, instead of driving the line like a monopole, I simply plunked a source into the wire skeleton of the "shield." But to return to your own published model, I've played with the length of wire 26 after discovering it emerged from both ends of the coax. I don't put much credit to Cecil's invention of topics, so I am unaware if this wire length meets some criteria (even if it did, I would still suspect the detail would have been spurious). Be that as it may. After truncating the wire 26 so that it did not come anywhere closer to the mouth of the coax (either end) than 5 feet, "induced" currents plummeted like a rock. 73's Richard Clark, KB7QHC Article: 226386 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <12b328b1f0jgsd9@corp.supernews.com> Subject: Re: Quarterwave vertical with radials Message-ID: Date: Tue, 11 Jul 2006 20:52:54 -0700 "Roy Lewallen" wrote in message news:12b328b1f0jgsd9@corp.supernews.com... < snip > > > A normal ground plane is a large sheet of metal that reflects the radio wave > > emitted by the radiating element. > > "Normal"? Where have you seen an antenna mounted over a metal ground > plane many wavelengths in diameter? Perhaps a UHF antenna in the middle > of the top of a car, but that's about it. > < snip > Which prompts me to ask a question: If a quarterwave vertical antenna has many radials only a few feet above the ground, and these radials could be made progressively longer and longer, does the antenna eventually fail to "know" where the ground is? How long is "very long" to bring this about (if it happens)? I kicked some numbers around. By the formula two times antenna_length-squared divided by wavelength [2D^2/lambda], I make the far-field distance for a 14 MHz quarterwave vertical be only 2.5 meters [less than a quarter wavelength] ... but typical radials are already longer than that, aren't they? So this isn't a near-field/far-field boundary issue, is it? Article: 226387 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <4n6ql.jaf.19.1@news.alt.net> <12b8k3ugq5ovgeb@corp.supernews.com> <44b45621$0$1016$39cecf19@news.twtelecom.net> Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers IfNecesssary. Message-ID: Date: Tue, 11 Jul 2006 21:09:41 -0700 "Tom Ring" wrote in message news:44b45621$0$1016$39cecf19@news.twtelecom.net... < snip > > This whole thing was started by what's called a troll. It was forged, > not from the person it purports to be from. Many of the "responses" are > also forged, and from the same person or his cohorts. > Yes, but I think this was more an odd attempt to be funny. Suggest all go back and look at whom he said he "will not hesitate to contact" ... then decide how to take the OP. I bet he didn't mean to spin up so many people. Article: 226388 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Antenna optimization Date: Tue, 11 Jul 2006 21:59:15 -0700 Message-ID: <12b90d4hgsajp36@corp.supernews.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <53rco3-rti.ln1@p400bob.personal.cox.net> Bob Bob wrote: > Yes! > > I think EZNEC has a optimization function as you stated. I know 4NEC2 > does as I have used it many times.. No, sorry, EZNEC doesn't have any optimization capability. Roy Lewallen, W7EL Article: 226389 of rec.radio.amateur.antenna From: Subject: Re: Need help on QRM rejection ( WITHOUT A BEAM !!) Date: Wed, 12 Jul 2006 00:42:10 -0500 Message-ID: References: On Tue, 11 Jul 2006 10:00:01 -0500, Bob Bob wrote: > >No doubt I will be mentioning stuff you have already tried and tested... >I assume you mean QRN rather than QRM? Hi Bob yes, QRN it is ... how foolish of me. sigh but, this evening I just tried 4mhz and saw S/N of 9+ and going up to 7mhz, the QRN is even worse. there is no real static or tones or motorboating or anything distinctive. It is just plain, old NOISE!! it is so high that I cannot even hear my NCS very well and he is about 30 mi North of me. Even 75m should allow local intelligibility and reception regardless of propagation. A fellow on another site or forum suggested an NVIS as you have. I am considering a 63' wire about 10 ft above and across the yard (which has about 4" of iron ore for a base) so I should get good reflectivity espec with all this rain. I might attach it to a 15x20' steel patio cover at one end if I can find a way to insulate the cover from the pipes into the ground. or do I want it grounded? I am getting so confused and frustrated. I can certainly remember in the 1950s how low the QRN was except for sunspots, etc. or someone with a "noisy" auto engine. The antenna manual put out by ARRL has gotten so complicated that at this point, I am not "googling" as I should be and am instead, asking for help on the usenet, etc. thanks for your reply and those from others will try some of your suggestions to include a game of fox and hounds have to remember, this is an ICOM 736 which is what? 40 yrs old?? it does not have some of the circuitry yours has. But then, it is almost completely analog, which i like. Turn a know or button and it does something. = no menus to speak of. 73s K5DAM chas -- Charles L Hamilton Houston, TX chasm@texas.net If you are reading this in English, Thank a Vet!! If you are reading this in Spanish, Thank the US Senate!! Article: 226390 of rec.radio.amateur.antenna From: Subject: Re: Need help on QRM rejection ( WITHOUT A BEAM !!) Date: Wed, 12 Jul 2006 00:44:24 -0500 Message-ID: References: Dave wrote: > >Or, are you hearing lots of static QRN? [N]atural noise sources? plain old ... usually background, noise. QRN. but it is so loud that I cannot hear traffic thru it on USB. This is really bad, especially on a MARS NET call. 73s chas K5DAM -- Charles L Hamilton Houston, TX chasm@texas.net If you are reading this in English, Thank a Vet!! If you are reading this in Spanish, Thank the US Senate!! Article: 226391 of rec.radio.amateur.antenna Subject: Re: Antenna optimization From: Dave Oldridge References: <44b3afc1$0$990$ba4acef3@news.orange.fr> Message-ID: Date: Wed, 12 Jul 2006 06:05:47 GMT "JC" wrote in news:44b3afc1$0$990$ba4acef3@news.orange.fr: > Is there a software which can design an antenna (like EZNEC or similar > ) then allows to automatically optimize its dimensions according to > given requirements: max gain, F/B, min swr... and accepted dimensional > parameters changes: boom length, spacing.... > JC http://mmhamsoft.amateur-radio.ca/files/programs/MMANA-GAL-65.zip -- Dave Oldridge+ ICQ 1800667 Article: 226392 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Induced signal? Date: 11 Jul 2006 23:11:22 -0700 Message-ID: <1152684682.327067.323630@i42g2000cwa.googlegroups.com> References: Richard, You hit this nail on the head, for sure: > All the issues you focus on are quite particular and specific, and > perhaps too much so. I find them equally interesting and you ask > reasonable questions. Unfortunately, you question above suffers from > every problem imaginable for measuring, and any report you get without > considerable qualification is probably sheer fancy. It suffers from a > version of Heisenberg's problem of disturbing what you attempt to > measure, and invalidating everything in the process. I don't have much trouble with the antennas I actually build. The aluminum and wire I sling around tend to behave. I do have some vested interest in overspecific modeling in the sense that since I'm deploying all my antennas from the balcony of my apartment (with its overhanging roof), and don't have much space to build, adjustments and pruning are very hard to do. Some performance gains can certainly be had by adjustment... but in my situation now it's so much easier to push bits around in EZNEC. This one, though, was just pure impractical theoretical curiosity. That, and a little bit of being concerned that people seemed to "know" the answer, that the answer was obvious, and, well, I didn't think it was. The current in real experiment would be, as you pointed out, pretty much impossible to measure without disturbing it. But as I see it, from a practical standpoint, in a real system where you're using the shield of a piece of coax as an antenna , the current in the center conductor never matters. The existence of the current matters, at least as a learning experience. It matters in the sense that some seem to think that there couldn't be a current, just because a piece of coax is "shielded". Or because the center conductor is "floating". It's precisely the fact that the center conductor is "floating" that makes the (probably) weak coupling at the ends important. Thanks for posting your results. What you describe certainly jives with the fuzzy idea that I've got of what's doing the coupling ... or at least where it's happening. Of course, the tube without center conductor is certainly a waveguide well below cutoff, so we've got solid footing saying a short wire inside a long conductive tube a small fraction of a wavelength in diameter will have little current on it... and the model also exhibits this. I'm done with this one unless I find a leadless current meter (small, battery powered with an A/D converter and optical fiber out?) and a big piece of copper pipe laying around! 73, Dan Article: 226393 of rec.radio.amateur.antenna From: "Arie" <4nec2@gmx.net> Subject: Re: Antenna optimization Date: 12 Jul 2006 03:22:32 -0700 Message-ID: <1152699752.608202.323470@p79g2000cwp.googlegroups.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> > MMANA does what you want and it's free. However, note that because MMANA being a MiniNec based program, when using none vertical elements below 0.2 wavelengths accuracy rapidly drops. If you'd like to optimize on (lower) HF, a Nec based program is prefered Furthermore, I don't think optimization is out. But, if it should be so, it still will learn you very much about the effect of antenna dimension changing on antenna performance. And last but not least, because of being freeware, experimenting with MMANA or 4nec2 [http://home.ict.nl/~arivoors/] will cost you nothing (besides a little studying), weather you would like to use a traditional optimizer of a genetic algorithm based optimizer. Arie. Article: 226394 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Need help on QRM rejection ( WITHOUT A BEAM !!) References: Message-ID: <6A4tg.3299$2v.2542@newssvr25.news.prodigy.net> Date: Wed, 12 Jul 2006 10:57:06 GMT chasm@texas.net wrote: > plain old ... usually background, noise. QRN. > but it is so loud that I cannot hear traffic thru it on USB. > This is really bad, especially on a MARS NET call. Try borrowing a ClearSpeech speaker. Mine turns some signals from unreadable to readable. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226395 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Induced signal? Date: 12 Jul 2006 04:46:43 -0700 Message-ID: <1152704803.578463.295440@75g2000cwc.googlegroups.com> References: Cecil Moore wrote: > w8ji@akorn.net wrote: > > Cecil Moore wrote: > >> I have used that same circuit to switch a top hat > >> in and out. How much RF power did I lose by taking > >> that route? > > > > That is NOTHING like the problem the ZL on eHam had. > > Clutching at straws, are we? It's exactly like the ZL problem > except the relay is used to switch a top hat instead of a wire. > -- > 73, Cecil http://www.qsl.net/w5dxp Cecil, In your alleged system, you carried RF through the coax and used the coax as a swixcthing stub. In the other fellows system, he had a high impedance feed and had to get a relay conductor past the high impedance feed without affecting the system. They are TOTALLY different. Even a card carrying mensa member can't be that out of touch with a simple system like this. 73 Tom Article: 226396 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Quarterwave vertical with radials Date: 12 Jul 2006 04:50:19 -0700 Message-ID: <1152705019.953092.101550@m73g2000cwd.googlegroups.com> References: Tom Ring wrote: > w8ji@akorn.net wrote: > > > Maybe reading one of your own posts will jog your memory a bit. In it > > we see you VERY CLEARLY stated two radials would cancel each other's > > radiation. > > > > 73 Tom > > > > Won't matter, he'll have an explanation for it, and it will be anyone's > fault but his. > > tom > K0TAR You were right Tom. He came up with one and it wasn't his fault. Article: 226397 of rec.radio.amateur.antenna From: "Ulf B" Subject: Waterfront antennna Message-ID: Date: Wed, 12 Jul 2006 14:17:26 GMT Hello all experts and gurus, I am experimenting with a 18m (54tf) end fed slooping (30 degr) wire. The "bottom" end is located right at the waterfront and is also the feedpoint. (Automatic tuner.) I will use 16 radials ea 10m/30ft where 8 vill be in freshwater and the other burried in my lawn. I choose this length of antenna in order not to have a voltage/high impedance feedpoint on any the bands 160-6 which I will use. A fullblown vertical would of course be a better option but the slooping comes from the only available convinient atatchment point. I am also very restricted as far as "construction work" goes. The idéa is to have a "stealth" simple multiband antenna. Preliminary work mainly on lowbands gives good results for non DX work. So... does anyone of you gentlemen and women (?) have any experience/thoughts/idéas of this concept? Thanks in advance. SM0FKI /Ulf Article: 226398 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Induced signal? References: <1152607665.959599.175290@s13g2000cwa.googlegroups.com> <1152629374.119641.242380@s13g2000cwa.googlegroups.com> <1152642814.362640.247960@p79g2000cwp.googlegroups.com> <1152644696.098566.325300@m79g2000cwm.googlegroups.com> <1152645666.609883.321800@h48g2000cwc.googlegroups.com> <1152657483.200112.122940@35g2000cwc.googlegroups.com> <6yYsg.63956$fb2.47802@newssvr27.news.prodigy.net> <1152704803.578463.295440@75g2000cwc.googlegroups.com> Message-ID: Date: Wed, 12 Jul 2006 14:23:23 GMT w8ji@akorn.net wrote: > In your alleged system, you carried RF through the coax and used the > coax as a swixcthing stub. You seem to be confused by my actual system in my yard Vs the hypothetical piece of coax I introduced as a simplified example for discussion purposes. Forget the coax example. In my yard, I have run two wires up a piece of 1/4WL aluminum tubing to a relay which switched a top hat in and out just as the other fellow wanted to switch a wire in and out. The only thing that I would have to add to turn that system into switchable half-squares, like the other fellow has, would be two 3/4WL runs of wire. I suspect the SGC-230 autotuner at the base would match the new feedpoint impedance just fine. I've never seen an impedance it couldn't match. > In the other fellows system, he had a high impedance feed and had to > get a relay conductor past the high impedance feed without affecting > the system. The two physical configurations being discussed are *identical*, being 1/4WL of tubing through which two DC wires are routed. > They are TOTALLY different. Once again, you make an outrageous exclusive statement completely divorced from reality. If any one thing about the two antennas is not different, your statement is completely false. One wonders what compels you to make such strange assertions. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226399 of rec.radio.amateur.antenna From: "Steven Umbach" References: <44969559.30D72920@milestones.com> <44995516$0$11193$892e7fe2@authen.yellow.readfreenews.net> <1aOdnQMcX-kk9gTZnZ2dnUVZ_qadnZ2d@comcast.com> <129lvnf4h9st2d3@corp.supernews.com> <129m9ijcnshm47f@corp.supernews.com> <129ofcclvejs22f@corp.supernews.com> <0bjo92p0h2dfqcum243lc3u1mqv49nu10h@4ax.com> Subject: Re: OT: Outsourcing Date: Wed, 12 Jul 2006 09:26:44 -0500 Message-ID: Well said and beware of those trying to raise taxes on corporations. --- Steve "Cecil Moore" wrote in message news:lIZmg.104309$H71.44092@newssvr13.news.prodigy.com... > David wrote: > > Corporations pay way less than half the cost of running governments, > > Corporations don't pay any of the cost of running > governments - their customers pay it all. > -- > 73, Cecil http://www.qsl.net/w5dxp Article: 226400 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Quarterwave vertical with radials References: <12b560umsqr7033@corp.supernews.com> <1Jysg.129184$dW3.5355@newssvr21.news.prodigy.com> <1152578023.253600.314910@m73g2000cwd.googlegroups.com> <1152609735.071204.264590@m79g2000cwm.googlegroups.com> <1152647530.313784.53460@m73g2000cwd.googlegroups.com> <1152664193.502576.106990@s13g2000cwa.googlegroups.com> <44b456ae$0$1016$39cecf19@news.twtelecom.net> <1152705019.953092.101550@m73g2000cwd.googlegroups.com> Message-ID: Date: Wed, 12 Jul 2006 14:30:15 GMT w8ji@akorn.net wrote: > Tom Ring wrote: >> Won't matter, he'll have an explanation for it, and it will be anyone's >> fault but his. >> > You were right Tom. > He came up with one and it wasn't his fault. On the contrary, I confessed it was my fault for missing four days of postings and thus missing the "two and only two radial" context. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226401 of rec.radio.amateur.antenna From: "Frank's" References: Subject: Re: Waterfront antennna Message-ID: Date: Wed, 12 Jul 2006 15:19:07 GMT "Ulf B" wrote in message news:Wv7tg.8730$E02.2765@newsb.telia.net... > Hello all experts and gurus, > > I am experimenting with a 18m (54tf) end fed slooping (30 degr) wire. The > "bottom" end is located right at the waterfront and is also the feedpoint. > (Automatic tuner.) I will use 16 radials ea 10m/30ft where 8 vill be in > freshwater and the other burried in my lawn. I choose this length of > antenna in order not to have a voltage/high impedance feedpoint on any the > bands 160-6 which I will use. > > A fullblown vertical would of course be a better option but the slooping > comes from the only available convinient atatchment point. I am also very > restricted as far as "construction work" goes. The idéa is to have a > "stealth" simple multiband antenna. Preliminary work mainly on lowbands > gives good results for non DX work. > > So... does anyone of you gentlemen and women (?) have any > experience/thoughts/idéas of this concept? > > Thanks in advance. > > SM0FKI /Ulf I don't have any real experience with such an antenna, also not sure what you mean by sloping 30 deg. Is that 30 zenith, or elevation? Given a zenith angle of 30 degrees, the height will be about 47 ft and the end displaced by 27 ft from the ground plane center. Models for such an antenna indicate an input impedance of 14 - j 1982 ohms at 1.8 MHz. With such a structure the input voltage at the base feedpoint will be 5.8 kV RMS, with 100 W input. I have often considered such an antenna, but have never gotten around to actually putting it up. Regards, Frank (VE6CB) CM Sloping Vertical CE GW 1 27 0 27 46.7 0 0 0.1 0.0026706 GW 2 15 0 0 0.1 0 30 0.1 0.0026706 GM 1 9 0 0 36 0 0 0 002.002 GS 0 0 .3048 GE 1 GN 2 0 0 0 13.0000 0.0050 EX 0 1 11 00 7476.01578 0.00000 LD 5 1 1 27 5.8001E7 LD 5 2 1 15 5.8001E7 LD 5 3 1 15 5.8001E7 LD 5 4 1 15 5.8001E7 LD 5 5 1 15 5.8001E7 LD 5 6 1 15 5.8001E7 LD 5 7 1 15 5.8001E7 LD 5 8 1 15 5.8001E7 LD 5 9 1 15 5.8001E7 LD 5 10 1 15 5.8001E7 LD 5 11 1 15 5.8001E7 FR 0 1 0 0 1.8 1 RP 0 181 1 1000 -90 0 1.00000 1.00000 NE 0 1 1 11 10 0 0 1.0 1.0 1 EN Article: 226402 of rec.radio.amateur.antenna From: "Frank's" References: Subject: Re: Waterfront antennna Message-ID: Date: Wed, 12 Jul 2006 15:26:31 GMT > I don't have any real experience with such an antenna, also not sure > what you mean by sloping 30 deg. Is that 30 zenith, or elevation? > > Given a zenith angle of 30 degrees, the height will be about 47 ft > and the end displaced by 27 ft from the ground plane center. Models > for such an antenna indicate an input impedance of 14 - j 1982 ohms > at 1.8 MHz. With such a structure the input voltage at the base > feedpoint will be 5.8 kV RMS, with 100 W input. I have often > considered such an antenna, but have never gotten around to > actually putting it up. > > Regards, > > Frank (VE6CB) Typical, as usual I goofed. Changing the segmentation and not correcting for the feedpoint segment. The input impedance is in fact 5.467 - j 876.482, for an input voltage of 3.75 kV RMS, with 100 W applied. Corrected code below: CM Sloping Vertical CE GW 1 27 0 27 46.7 0 0 0.1 0.0026706 GW 2 15 0 0 0.1 0 30 0.1 0.0026706 GM 1 9 0 0 36 0 0 0 002.002 GS 0 0 .3048 GE 1 GN 2 0 0 0 13.0000 0.0050 EX 0 1 27 00 5301.416318 0.00000 LD 5 1 1 27 5.8001E7 LD 5 2 1 15 5.8001E7 LD 5 3 1 15 5.8001E7 LD 5 4 1 15 5.8001E7 LD 5 5 1 15 5.8001E7 LD 5 6 1 15 5.8001E7 LD 5 7 1 15 5.8001E7 LD 5 8 1 15 5.8001E7 LD 5 9 1 15 5.8001E7 LD 5 10 1 15 5.8001E7 LD 5 11 1 15 5.8001E7 FR 0 1 0 0 1.8 1 RP 0 181 1 1000 -90 0 1.00000 1.00000 NE 0 1 1 11 10 0 0 1.0 1.0 1 EN Article: 226403 of rec.radio.amateur.antenna From: "RHF" Subject: Re: OT: Outsourcing Date: 12 Jul 2006 09:14:10 -0700 Message-ID: <1152720850.662591.37690@b28g2000cwb.googlegroups.com> References: <44969559.30D72920@milestones.com> JB - Spoken like a True Red and White {Blue-in-the-Face} Canadian ~ RHF . . . . John Barnard wrote: > Cecil Moore wrote: > > David wrote: > >> Corporations pay way less than half the cost of running governments, > > > > Corporations don't pay any of the cost of running > > governments - their customers pay it all. > You are right! Corporations don't pay the cost of running governments. > They pay the cost of usurping governments! > > JB Article: 226404 of rec.radio.amateur.antenna From: Subject: Re: Need help on QRM rejection ( WITHOUT A BEAM !!) Date: Wed, 12 Jul 2006 11:18:16 -0500 Message-ID: References: <6A4tg.3299$2v.2542@newssvr25.news.prodigy.net> On Wed, 12 Jul 2006 10:57:06 GMT, Cecil Moore wrote: > >Try borrowing a ClearSpeech speaker. Mine turns >some signals from unreadable to readable. I have one which I purchased for the mobile rig. will try to figure out how to plug it in here... probably thru a phone jack. ever try to find old PL-1 phone jacks, locally ? better question, why hadn't ICOM gone to the banana jack by the time this 736 was built?? in fact, have they ever gone to a smaller phone jack? have not been able to afford the cover charge to look at a modern ICOM HF rig. 73s chas K5DAM -- Charles L Hamilton Houston, TX chasm@texas.net If you are reading this in English, Thank a Vet!! If you are reading this in Spanish, Thank the US Senate!! Article: 226405 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: New Swiss antenna system... Date: Wed, 12 Jul 2006 09:19:14 -0700 Message-ID: References: <1152588973.511463.222930@p79g2000cwp.googlegroups.com> <12b7qb5ohcdhk5b@corp.supernews.com> On Tue, 11 Jul 2006 23:29:01 +0100, Iain Kelly wrote: >Whilst the above comments are very well made I must say that there are >some good ideas with this whole HAP thing. A lot of my lecturers and >professors are involved with a big chunk of the research into this >venture, Hi Ian, This is called "conflict of interest," which discounts those same lecturers' and professors' credentials. >and for high speed broadband data access the idea is good. The >points made about cellular systems are true, but it is my understanding >that in densely populated areas there would be more HAPs up in the air, >each could have multiple cells potentially... You've missed the point Roy made. Adding connections (more HAPs) does not add more bandwidth. Those extra HAPs will be competing for the same (now diminishing by proportion) spectrum. >Having said that I do get the impression from some research seminars >I've been to on the subject, that there is still a lot of work to be >done before the proposal can be realised to it's full potential, but I >do think the principle is sound. When there's existing hardware (after all, no one is telling the consumers to throw away their phones and buy HAP versions), and Hindenberg technology is a century old; then any proviso "there is still a lot of work to be done" translates into SEND MORE MONEY - a message tape with an infinite loop. Ask researcher1: "can I float a balloon?" researcher1: "Sure, no problem." Ask researcher2: "can I transmit and receive from a height?" researcher2: "Sure, no problem." Ask researcher3: "can I find a stabilizing platform?" researcher3: "Sure, no problem." Ask researcher4: "can more connections serve more customers?" researcher4: "Sure, no problem." The sum is not equal to the whole: Ask customers: "can you still hear me?" customers: "What the ****! My line is dead." 73's Richard Clark, KB7QHC Article: 226406 of rec.radio.amateur.antenna From: "RHF" Subject: Re: OT: Outsourcing Date: 12 Jul 2006 09:23:26 -0700 Message-ID: <1152721405.952131.202260@i42g2000cwa.googlegroups.com> References: <1149441418.531073.162560@j55g2000cwa.googlegroups.com> DaviD, So posting here is your sole employment {Business} ~ RHF . . . . David wrote: > On Thu, 22 Jun 2006 15:34:52 -0500, "DrDeath" > wrote: > > > > > >India is not a country we rely on to build super companies (for lack of a > >better term). Take a look at what we send to India. Toxic chemical factories > >that would be choked to death by special interest groups and politicians. We > >also outsource technical support, which is a waste of time and money, good > >thing companies don't pay them much, but it's a cheap way of saying "we have > >tech support" without truly having it. Look at the shoe mfg. industry, all > >moved to third world slave labor countries. Good for the shoe industry as > >they no longer have to deal with unions and we keep management and > >development in countries that have the talent and resources to maintain > >state of the art products. Look at how the auto industry has changed. They > >sent 1000s of jobs overseas to cut down on union labor (with management and > >R&D in the US), and the Japs are opening plants in the US (with management > >and R&D in Japan) that will never deal with the UAW. I could go on forever > >with this post (and talk about NAFTA), but will end my rave at this point. > >BTW, changed subject header as it didn't seem to fit. I would have trimmed a > >few NGs but am unsure what groups you are subscribed to. > > > > - The purpose of business is to keep people busy. Article: 226407 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Antenna optimization Date: Wed, 12 Jul 2006 09:27:51 -0700 Message-ID: References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> On 11 Jul 2006 13:45:49 -0700, w0zv@yahoo.com wrote: > >Ben AD7GD wrote: > >> On 2006-07-11, w0zv@yahoo.com wrote: >> > >> > Unfortunately K6STI no longer markets his software to hams (due to >> > software piracy issues). Hopefully you can find someone with a copy >> > who can optimize your initial results. >> >> Careful, you're pegging my irony meter. > >Why? The documentation says: > >************************************************************************ > This software is copyrighted. It has been provided to > you on the condition that you will not sell, rent, lend, give > away, or otherwise transfer the software to others. >************************************************************************ > >As I read it, there is no problem if I use it to optimize a model >for someone else. I'm NOT volunteering to do that however. Hi Bill, Strange as it may seem, yes you would be in violation. Copyright is the author's total monopoly to insure his revenue from his creation. If you disrupt that revenue flow you are breaking the law. You said it yourself, he doesn't market to amateurs - rather professionals who will pay for the LICENSE to use it professionally. If they choose to do someone a favor, and drop their fee, that is their hit, not his. He granted them the right, by LICENSE and at a cost, to lose money if they wish. Hence the irony meter being pegged. 73's Richard Clark, KB7QHC Article: 226408 of rec.radio.amateur.antenna From: "RHF" Subject: Re: OT: Outsourcing Date: 12 Jul 2006 09:40:07 -0700 Message-ID: <1152722407.879793.183020@m73g2000cwd.googlegroups.com> References: <44969559.30D72920@milestones.com> David wrote: > On Fri, 23 Jun 2006 14:14:17 -0500, "DrDeath" > wrote: > > >"David" wrote in message > >news:u9tn92tmv5angta69k852on9jq12brc412@4ax.com... > >> On Thu, 22 Jun 2006 18:22:57 -0500, "DrDeath" > >> wrote: > >> > >>> > >> > >>>> The purpose of business is to keep people busy. > >>>> > >>>No, It is to make money. > >>> > >>> > >> Then it would be called moneyness. > > > >Then I guess all those Fotrune 500 people have it wrong as they are in > >buisness for making money. Even my boss hired me to make money, not to keep > >me busy. Hell I can keep myself busy. > > > >> > >> Those gated communities won't protect you from the thundering hordes > >> of hungry people. > >> > > > >Gated communities? I live in the sticks armed to the teeth. They can eat the > >dead bodies I leave in the yard. > > > > > You're a tough guy. > > During a more civilised time a company went into business to provide > jobs and make profits and to be part of a community. Nowadays > corporations are extranational, have no local ties and just milk > markets dry and move on. > > Corporations pay way less than half th cost of running governments, > even though they are the major beneficieries of what governments > provide. This is because we let them write their own rules. DaviD, The vast majority of 'businesses' are "Sole Proprietorships" One Man trying to Create a Job for Himself and Ear a Living. -IF- He is Good & Lucky - His Business will Expand and He will be able to Hire Other People and Employ Them Too. Small Business is the Foundation of Bigger {BIG} Business. Three Points to Remember about Being-in-Business : # 1 - Become Profitable # 2 - Expand and Grow # 3 - Continue in Business business - think small and grow big ~ RHF . . . . Article: 226409 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Wed, 12 Jul 2006 09:47:36 -0700 Message-ID: References: <30954.oidi09.d0904.ddoi0@qkd.org> ORIGINAL MESSAGE: On Wed, 12 Jul 2006 16:06:55 GMT, dj@qkd.net (Dirk) wrote: >Ham's care more about operating appliances than knowing how to save a lives. > >:-( ------------ REPLY SEPARATOR ------------ 1 2 3 4 5 6 7 8 9 10 / / / / / / / / TROLL-O-METER Bill, W6WRT Article: 226410 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> Subject: Re: Antenna optimization Message-ID: Date: Wed, 12 Jul 2006 13:08:51 -0400 Is this lawyertwist's interpretation? Like it is not COPYright it is REVENUEright? Don't you anybody ask to read my copyrighted magazine issue! You will disrupt the revenue flow of the publisher/authors. Oh, and don't read any magazines in your dentist's office while you are shaking for the treatment. You could be imprisoned, but Sandy Burglar can give disks to Chinese and stuff his pants with classified documents with impunity. If I paid for the software/book and I use it 24 hours a day or once a year is not anybody's freakin business. Copyright is about COPYING or selling unauthorized copies. Gimme a break, or yuoze guyze just love to argue phantom threads? Get on the air. Tesla Radioclub fired up from it's new QTH as N2T celebrating 150th birthday of this greatest engineering genius (who would be turned into idiot by this NG guruship). Yuri, K3BU www.TeslaRadio.org "Richard Clark" wrote in message news:fd8ab2lmumsd1d2bth9n1mis7u4chg1vjm@4ax.com... > On 11 Jul 2006 13:45:49 -0700, w0zv@yahoo.com wrote: > >> >>Ben AD7GD wrote: >> >>> On 2006-07-11, w0zv@yahoo.com wrote: >>> > >>> > Unfortunately K6STI no longer markets his software to hams (due to >>> > software piracy issues). Hopefully you can find someone with a copy >>> > who can optimize your initial results. >>> >>> Careful, you're pegging my irony meter. >> >>Why? The documentation says: >> >>************************************************************************ >> This software is copyrighted. It has been provided to >> you on the condition that you will not sell, rent, lend, give >> away, or otherwise transfer the software to others. >>************************************************************************ >> >>As I read it, there is no problem if I use it to optimize a model >>for someone else. I'm NOT volunteering to do that however. > > Hi Bill, > > Strange as it may seem, yes you would be in violation. > > Copyright is the author's total monopoly to insure his revenue from > his creation. If you disrupt that revenue flow you are breaking the > law. You said it yourself, he doesn't market to amateurs - rather > professionals who will pay for the LICENSE to use it professionally. > If they choose to do someone a favor, and drop their fee, that is > their hit, not his. He granted them the right, by LICENSE and at a > cost, to lose money if they wish. > > Hence the irony meter being pegged. > > 73's > Richard Clark, KB7QHC Article: 226411 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: If you had to use CW to save someone's life, would that person References: <30954.oidi09.d0904.ddoi0@qkd.org> Message-ID: Date: Wed, 12 Jul 2006 17:14:47 GMT Dirk wrote: > Ham's care more about operating appliances than knowing how to save a lives. How many times in the entire history of amateur radio has a ham used CW to actually save a life? One would think there would be a book full of examples by now. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226412 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Need help on QRM rejection ( WITHOUT A BEAM !!) References: <6A4tg.3299$2v.2542@newssvr25.news.prodigy.net> Message-ID: Date: Wed, 12 Jul 2006 17:18:18 GMT chasm@texas.net wrote: > On Wed, 12 Jul 2006 10:57:06 GMT, Cecil Moore wrote: >> Try borrowing a ClearSpeech speaker. Mine turns >> some signals from unreadable to readable. > > I have one which I purchased for the mobile rig. > will try to figure out how to plug it in here... probably thru a phone jack. > ever try to find old PL-1 phone jacks, locally ? > better question, why hadn't ICOM gone to the banana jack by the time this 736 > was built?? in fact, have they ever gone to a smaller phone jack? have not > been able to afford the cover charge to look at a modern ICOM HF rig. I have a drawer full of misc adapters gathered over the years for just such a purpose. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226413 of rec.radio.amateur.antenna From: "an old freind" Subject: Re: If you had to use CW to save someone's life, would that person die? Date: 12 Jul 2006 10:24:55 -0700 Message-ID: <1152725095.545555.121150@h48g2000cwc.googlegroups.com> References: <30954.oidi09.d0904.ddoi0@qkd.org> Dirk wrote: > Ham's care more about operating appliances than knowing how to save a lives. > > :-( if i was at my home station is no they would not die and I am as no code as they come I down right hate the mode and yet y pc and station is quite able to work cw as needed to save a life if it was needed Article: 226414 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 13:26:22 -0400 From: "John L. Sielke" Subject: Re: OT: Outsourcing References: <44969559.30D72920@milestones.com> <44995516$0$11193$892e7fe2@authen.yellow.readfreenews.net> <1aOdnQMcX-kk9gTZnZ2dnUVZ_qadnZ2d@comcast.com> <129lvnf4h9st2d3@corp.supernews.com> <129m9ijcnshm47f@corp.supernews.com> <129ofcclvejs22f@corp.supernews.com> <0bjo92p0h2dfqcum243lc3u1mqv49nu10h@4ax.com> <1152720850.662591.37690@b28g2000cwb.googlegroups.com> Message-ID: <7ZWdnbeedbkjrSjZnZ2dnUVZ_oudnZ2d@comcast.com> RHF wrote: > JB - Spoken like a True Red and White > {Blue-in-the-Face} Canadian ~ RHF > . > . > . . > > John Barnard wrote: >> Cecil Moore wrote: >>> David wrote: >>>> Corporations pay way less than half the cost of running governments, >>> Corporations don't pay any of the cost of running >>> governments - their customers pay it all. >> You are right! Corporations don't pay the cost of running governments. >> They pay the cost of usurping governments! >> >> JB > It' all because back in the 60's all those draft-dodger types went to Canada. Canada not only welcomed them, but allowed them to breed. The gene pool has never been the same. Article: 226415 of rec.radio.amateur.antenna From: Boomhauer Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Wed, 12 Jul 2006 17:29:25 -0000 Message-ID: <12bacbllpabrpd1@corp.supernews.com> References: <30954.oidi09.d0904.ddoi0@qkd.org> Dirk wrote: > > Ham's care more about operating appliances than knowing how to save a lives. > > :-( au revoir adiós arrivederci Auf Wiedersehen Article: 226416 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: If you had to use CW to save someone's life, would that person Date: Wed, 12 Jul 2006 12:38:53 -0500 Message-ID: <12bactjanpufjfc@corp.supernews.com> References: <30954.oidi09.d0904.ddoi0@qkd.org> Cecil Moore wrote: > Dirk wrote: > >> Ham's care more about operating appliances than knowing how to save a >> lives. > > > How many times in the entire history of amateur radio > has a ham used CW to actually save a life? One would > think there would be a book full of examples by now. A ham operator intercepted the SOS from the RMS Titanic. Article: 226417 of rec.radio.amateur.antenna From: "an old freind" Subject: Re: If you had to use CW to save someone's life, would that person die? Date: 12 Jul 2006 10:46:53 -0700 Message-ID: <1152726413.592316.117800@s13g2000cwa.googlegroups.com> References: <30954.oidi09.d0904.ddoi0@qkd.org> David G. Nagel wrote: > Cecil Moore wrote: > > > Dirk wrote: > > > >> Ham's care more about operating appliances than knowing how to save a > >> lives. > > > > > > How many times in the entire history of amateur radio > > has a ham used CW to actually save a life? One would > > think there would be a book full of examples by now. > > A ham operator intercepted the SOS from the RMS Titanic. how many life were saved thereby the Carpathia wheard the call and arrived to save some folks what role did the ARS playing in saving even one life that sorry day? Article: 226418 of rec.radio.amateur.antenna From: paggonzalez@gmail.com Subject: Re: Reradiating RF signals from Satellital Modem Date: 12 Jul 2006 10:55:44 -0700 Message-ID: <1152726944.011458.76070@75g2000cwc.googlegroups.com> References: <1152298653.803900.283720@s13g2000cwa.googlegroups.com> Jerry Martes ha escrito: > wrote in message > news:1152298653.803900.283720@s13g2000cwa.googlegroups.com... > > I'm to install a satellital modem (Globalstar GSP-1620) in a place > > where there's no full direct sky visibility due to some metallic > > obstacules. > > To overcome this problem I'm thinking of placing a reradiating antenna > > or RF repeater over the top of the highest obstacule, facing the real > > GSP1620 antenna down on the ground. > > > > The GSP1620 has two RF frequencies, one for TX (1610-1625 Mhz) and > > another for RX (2484-2499 Mhz). Does anyone have any ideas on how to > > build up such reradiating antenna and/or RF repeater ? Is there any > > commercial product similar to this ? > > > > Thanks a lot. > > Pablo > > Hi Pablo > > I am curious about your globalstar instalation. What kind of antenna will > you use at the location that "sees" the satellites? > And, why is it *not* OK to use coax cable from the remote antenna to the > telephone in the shadows? > > I am currently trying to build an antenna for Chris W. for his Globalstar > satelite phone. > > Jerry Jerry, For the location that actually sees the satellites the antenna must be an omnidirectional one ('cause globalstar constelation is LEO), perhaps the one that comes with the GSP-1620 (check http://www.globalstarusa.com/en/data/data_display.php?id=6). Since the OEM modem will be on the ground and since I cannot use any coax cable between them, I'm trying to find a wireless alternative, i.e. place an omnidirectional antenna over the highest obstacule and forward/repeat that RF signal down thru a directive antenna back to the ground where another (to be build) directive antenna (to avoid multipath satellite fixes) is attached to the modem. My question is about how to build such forwarding/repeating RF device and the corresponding directive antenna for both ends. Regards, Pablo Article: 226419 of rec.radio.amateur.antenna From: "Ulf B" References: Subject: Re: Waterfront antennna Message-ID: Date: Wed, 12 Jul 2006 18:04:01 GMT > Typical, as usual I goofed. Changing the segmentation and not > correcting for the feedpoint segment. The input impedance is > in fact 5.467 - j 876.482, for an input voltage of 3.75 kV RMS, > with 100 W applied. >> >> Regards, >> >> Frank (VE6CB) > Thanks Frank, 30 degrees is the slanting angle ref to ground. The azimuth is not important for this discussion. I would appreciate if you could do the same calculation for 3.75 MHz. This would help me estimate my ground losses based on the SWR measurements I have done. On this freq the SWR is at a minimum with a SWR 1.2 reading. Regards SM0FKI / Ulf Article: 226420 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: If you had to use CW to save someone's life, would that person References: <30954.oidi09.d0904.ddoi0@qkd.org> <12bactjanpufjfc@corp.supernews.com> Message-ID: <05btg.118974$H71.118121@newssvr13.news.prodigy.com> Date: Wed, 12 Jul 2006 18:21:48 GMT David G. Nagel wrote: > Cecil Moore wrote: >> How many times in the entire history of amateur radio >> has a ham used CW to actually save a life? One would >> think there would be a book full of examples by now. > > A ham operator intercepted the SOS from the RMS Titanic. Did that save even one life? If the Titanic's CW operator had not bullied the California's CW operator off the air, the California might have saved the day. But after such shabby treatment from the Titanic's arrogant CW operator, the California's CW operator shut down and turned in. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226421 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Antenna optimization Date: Wed, 12 Jul 2006 11:26:33 -0700 Message-ID: <9mfab293frnaarqolpejemllktd6d1ru5e@4ax.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> On Wed, 12 Jul 2006 13:08:51 -0400, "Yuri Blanarovich" wrote: > Gimme a break, or yuoze guyze just love to argue Talk about bellyaching.... Article: 226422 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: If you had to use CW to save someone's life, would that person Date: Wed, 12 Jul 2006 13:33:22 -0500 Message-ID: <12bag3q7hc7u723@corp.supernews.com> References: <30954.oidi09.d0904.ddoi0@qkd.org> <12bactjanpufjfc@corp.supernews.com> <1152726413.592316.117800@s13g2000cwa.googlegroups.com> an old friend wrote: > David G. Nagel wrote: > >>Cecil Moore wrote: >> >> >>>Dirk wrote: >>> >>> >>>>Ham's care more about operating appliances than knowing how to save a >>>>lives. >>> >>> >>>How many times in the entire history of amateur radio >>>has a ham used CW to actually save a life? One would >>>think there would be a book full of examples by now. >> >>A ham operator intercepted the SOS from the RMS Titanic. > > how many life were saved thereby the Carpathia wheard the call and > arrived to save some folks what role did the ARS playing in saving even > one life that sorry day? > We aren't talking about failure to receive a CW SOS. Those ships that responded did so after receiving word of the sinking by radio. They saved many lives from the lifeboats which would otherwise have been lost to the cold. Dave N Article: 226423 of rec.radio.amateur.antenna From: "Jerry Martes" References: <1152298653.803900.283720@s13g2000cwa.googlegroups.com> <1152726944.011458.76070@75g2000cwc.googlegroups.com> Subject: Re: Reradiating RF signals from Satellital Modem Message-ID: Date: Wed, 12 Jul 2006 18:45:46 GMT wrote in message news:1152726944.011458.76070@75g2000cwc.googlegroups.com... > > Jerry Martes ha escrito: > >> wrote in message >> news:1152298653.803900.283720@s13g2000cwa.googlegroups.com... >> > I'm to install a satellital modem (Globalstar GSP-1620) in a place >> > where there's no full direct sky visibility due to some metallic >> > obstacules. >> > To overcome this problem I'm thinking of placing a reradiating antenna >> > or RF repeater over the top of the highest obstacule, facing the real >> > GSP1620 antenna down on the ground. >> > >> > The GSP1620 has two RF frequencies, one for TX (1610-1625 Mhz) and >> > another for RX (2484-2499 Mhz). Does anyone have any ideas on how to >> > build up such reradiating antenna and/or RF repeater ? Is there any >> > commercial product similar to this ? >> > >> > Thanks a lot. >> > Pablo >> >> Hi Pablo >> >> I am curious about your globalstar instalation. What kind of antenna >> will >> you use at the location that "sees" the satellites? >> And, why is it *not* OK to use coax cable from the remote antenna to >> the >> telephone in the shadows? >> >> I am currently trying to build an antenna for Chris W. for his >> Globalstar >> satelite phone. >> >> Jerry > > Jerry, > > For the location that actually sees the satellites the antenna must be > an omnidirectional one ('cause globalstar constelation is LEO), perhaps > the one that comes with the GSP-1620 (check > http://www.globalstarusa.com/en/data/data_display.php?id=6). Since the > OEM modem will be on the ground and since I cannot use any coax cable > between them, I'm trying to find a wireless alternative, i.e. place an > omnidirectional antenna over the highest obstacule and forward/repeat > that RF signal down thru a directive antenna back to the ground where > another (to be build) directive antenna (to avoid multipath satellite > fixes) is attached to the modem. My question is about how to build such > forwarding/repeating RF device and the corresponding directive antenna > for both ends. > > Regards, > Pablo Hi Pablo The site you referanced implies that there is only one antenna supplied with this Globalstar GSP1620. Your text indicated that the GSP 1620 sends and receives signals on two widely seperated frequencies (1.62 GHz ans 2.4 GHz). Although I would like to know more about how the GSP 1620 works, this is probably not the right place for me to get educated. I'll be impresed if you manage to make dual frequency system work by using radiated RF to connect between a remote location and the Antenna. If there was any posibility that the entire Modum *and* Antenna could be located up at the location where the satellites can see it, you could (maybe) create a RF link between the GSP 1620 Modum and the remote location. Jerry Article: 226424 of rec.radio.amateur.antenna From: paggonzalez@gmail.com Subject: Re: Reradiating RF signals from Satellital Modem Date: 12 Jul 2006 12:34:19 -0700 Message-ID: <1152732859.041808.322940@i42g2000cwa.googlegroups.com> References: <1152298653.803900.283720@s13g2000cwa.googlegroups.com> Jerry Martes ha escrito: > wrote in message > news:1152726944.011458.76070@75g2000cwc.googlegroups.com... > > > > Jerry Martes ha escrito: > > > >> wrote in message > >> news:1152298653.803900.283720@s13g2000cwa.googlegroups.com... > >> > I'm to install a satellital modem (Globalstar GSP-1620) in a place > >> > where there's no full direct sky visibility due to some metallic > >> > obstacules. > >> > To overcome this problem I'm thinking of placing a reradiating antenna > >> > or RF repeater over the top of the highest obstacule, facing the real > >> > GSP1620 antenna down on the ground. > >> > > >> > The GSP1620 has two RF frequencies, one for TX (1610-1625 Mhz) and > >> > another for RX (2484-2499 Mhz). Does anyone have any ideas on how to > >> > build up such reradiating antenna and/or RF repeater ? Is there any > >> > commercial product similar to this ? > >> > > >> > Thanks a lot. > >> > Pablo > >> > >> Hi Pablo > >> > >> I am curious about your globalstar instalation. What kind of antenna > >> will > >> you use at the location that "sees" the satellites? > >> And, why is it *not* OK to use coax cable from the remote antenna to > >> the > >> telephone in the shadows? > >> > >> I am currently trying to build an antenna for Chris W. for his > >> Globalstar > >> satelite phone. > >> > >> Jerry > > > > Jerry, > > > > For the location that actually sees the satellites the antenna must be > > an omnidirectional one ('cause globalstar constelation is LEO), perhaps > > the one that comes with the GSP-1620 (check > > http://www.globalstarusa.com/en/data/data_display.php?id=6). Since the > > OEM modem will be on the ground and since I cannot use any coax cable > > between them, I'm trying to find a wireless alternative, i.e. place an > > omnidirectional antenna over the highest obstacule and forward/repeat > > that RF signal down thru a directive antenna back to the ground where > > another (to be build) directive antenna (to avoid multipath satellite > > fixes) is attached to the modem. My question is about how to build such > > forwarding/repeating RF device and the corresponding directive antenna > > for both ends. > > > > Regards, > > Pablo > > > Hi Pablo > > The site you referanced implies that there is only one antenna supplied > with this Globalstar GSP1620. Your text indicated that the GSP 1620 sends > and receives signals on two widely seperated frequencies (1.62 GHz ans 2.4 > GHz). > Although I would like to know more about how the GSP 1620 works, this is > probably not the right place for me to get educated. > I'll be impresed if you manage to make dual frequency system work by using > radiated RF to connect between a remote location and the Antenna. > If there was any posibility that the entire Modum *and* Antenna could be > located up at the location where the satellites can see it, you could > (maybe) create a RF link between the GSP 1620 Modum and the remote location. > > Jerry That's correct, there's only one antenna that handles both frequencies. In the bottom of the antenna you have two SMA connectors, one for TX and other for RX. In case you are further interested in this modem and its capabilities you can download the integrator's manual from http://common.globalstar.com/doc/common/en/products/gsp1620_integrator_manual.pdf Well I certanly do hope to get around this problem, since I cannot place both the modem and antenna in the same higher spot. Regards, Pablo Article: 226425 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 15:36:14 -0400 From: Dave Subject: Re: If you had to use CW to save someone's life, would that person References: <30954.oidi09.d0904.ddoi0@qkd.org> <12bactjanpufjfc@corp.supernews.com> Message-ID: David G. Nagel wrote: > Cecil Moore wrote: > >> Dirk wrote: >> >>> Ham's care more about operating appliances than knowing how to save a >>> lives. >> >> >> >> How many times in the entire history of amateur radio >> has a ham used CW to actually save a life? One would >> think there would be a book full of examples by now. > > > A ham operator intercepted the SOS from the RMS Titanic. Yep!! It happened once! Article: 226426 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Wed, 12 Jul 2006 12:44:01 -0700 Message-ID: References: <30954.oidi09.d0904.ddoi0@qkd.org> <1152725095.545555.121150@h48g2000cwc.googlegroups.com> ORIGINAL MESSAGE: On 12 Jul 2006 10:24:55 -0700, "an old freind" wrote: >if i was at my home station is no they would not die > >and I am as no code as they come I down right hate the mode and yet y >pc and station is quite able to work cw as needed to save a life if it >was needed ------------ REPLY SEPARATOR ------------ He apparently hates English too. Bill, W6WRT Article: 226427 of rec.radio.amateur.antenna From: "R. Scott" Subject: Re: If you had to use CW to save someone's life, would that person die? Message-ID: References: <30954.oidi09.d0904.ddoi0@qkd.org> Date: Wed, 12 Jul 2006 20:04:06 GMT > ------------ REPLY SEPARATOR ------------ > > 1 2 3 4 5 6 7 8 9 10 > \ > \ > \ > \ > \ > \ > \ > \ > TROLL-O-METER > > > Bill, W6WRT There I fixed it for you Article: 226428 of rec.radio.amateur.antenna From: w8ji@akorn.net Subject: Re: Voltage feeding a VHF yagi Date: 12 Jul 2006 13:39:25 -0700 Message-ID: <1152736765.706079.169140@p79g2000cwp.googlegroups.com> References: <1152233762.848358.152070@s13g2000cwa.googlegroups.com> Cecil Moore wrote: > > The half-wave end-fed antenna starts at point X. The feedline is > at point B. Here's what you said: > > w8ji@akorn.net wrote: > > 1.) You have a half-wave end-fed antenna. There has to be as much > > common mode current leaving the end of that point and flowing down the > > feedline as there is flowing out onto the antenna at that point. There > > isn't any exception to this rule. The STUB is a balanced transmission line. If you quoted the entire post everyone would see what I meant. Your constant little games of pulling things from context just waste time and ruin the purpose of technical forums. You really should quit that, and try to use the forums for education. 73 Tom Article: 226429 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 17:37:16 -0400 From: Dave Subject: Re: If you had to use CW to save someone's life, would that person References: <30954.oidi09.d0904.ddoi0@qkd.org> <12bactjanpufjfc@corp.supernews.com> Message-ID: Cecil Moore wrote: > Dave wrote: > >> David G. Nagel wrote: >> >>> A ham operator intercepted the SOS from the RMS Titanic. >> >> >> Yep!! It happened once! > > > If CW had not existed at the time, how would things have > turned out differently? If the present GPS-based system > had existed at the time, how would things have turned out? > Which system is presently inferior and virtually obsolete? C'mon Cecil, you've been licensed as long as I have. I Know you Know CW. Does that mean we're virtually obsolete? RE Titanic: The same result would have happened. The ship hit an iceberg in poor visibility. I don't think icebergs carry GPS transponders these days. Now, the Titanic's GPS; does it have transponder capability? The older GPS units do not. Anyway, after the crew slipped by the iceberg that ripped it open, the radio op gets on the air and reports "SOS" or equivalent. The nearest ships respond. Under conditions similar to 1914{?} the Titanic still sinks. Many people still die. But, now we know to 20 feet exactly where the ship was when it sank. GPS won't make a difference. Neither will CW today. I still enjoy CW. Article: 226430 of rec.radio.amateur.antenna From: w0zv@yahoo.com Subject: Re: Antenna optimization Date: 12 Jul 2006 14:41:59 -0700 Message-ID: <1152740519.671520.212240@p79g2000cwp.googlegroups.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> Richard Clark wrote: > On 11 Jul 2006 13:45:49 -0700, w0zv@yahoo.com wrote: > > > > >Ben AD7GD wrote: > > > >> On 2006-07-11, w0zv@yahoo.com wrote: > >> > > >> > Unfortunately K6STI no longer markets his software to hams (due to > >> > software piracy issues). Hopefully you can find someone with a copy > >> > who can optimize your initial results. > >> > >> Careful, you're pegging my irony meter. > > > >Why? The documentation says: > > > >************************************************************************ > > This software is copyrighted. It has been provided to > > you on the condition that you will not sell, rent, lend, give > > away, or otherwise transfer the software to others. > >************************************************************************ > > > >As I read it, there is no problem if I use it to optimize a model > >for someone else. I'm NOT volunteering to do that however. > > Hi Bill, > > Strange as it may seem, yes you would be in violation. > > Copyright is the author's total monopoly to insure his revenue from > his creation. If you disrupt that revenue flow you are breaking the > law. You said it yourself, he doesn't market to amateurs - rather > professionals who will pay for the LICENSE to use it professionally. > If they choose to do someone a favor, and drop their fee, that is > their hit, not his. He granted them the right, by LICENSE and at a > cost, to lose money if they wish. Hi Richard, 1. I paid for the non-professional version of K6STI's software while he WAS selling to amateurs. If you read his agreement carefully, it only prohibits transfer of the software itself. 2. I am not sure Brian markets YO to professionals any longer. There was apparently one well-known antenna manufacturer who bought his non-professional version and used it to design commercial antennas. I understand that this contributed to Brian's decision to exit the amateur business, but the main reason was someone in Europe hacked his RITTY program and posted it publicly. 3. If I were to do a gratis optimization for someone today, that would not violate the original license (i.e. transfer of the software itself) and Brian's revenue flow is not being broken since he no longer has any revenue flow from it. If a professional consultant were involved, they would have to show they sustained actual damages (i.e. lost business) which might be difficult to prove (not to mention the time and cost of doing so). > Hence the irony meter being pegged. No, that's the too-much-time-on-their-hands troll meter pegging. :-) It's a shame the piracy issue drove K6STI from the ham business. He is truly a genius and I love his AO, YO and DSP Blaster programs. I believe he's now doing something in the audiophile business...their gain and our loss. 73, Bill W4ZV. Article: 226431 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Wed, 12 Jul 2006 16:30:37 -0500 Message-ID: References: <30954.oidi09.d0904.ddoi0@qkd.org> Uh oh! Now a battle of the troll-o-meters... Really cute, Bill...I love it. 73, Steve, K9DCI P.S. I tilted my monitor and I see that this movement is a little out of balance on the sides. End-to-end balance is ok. Carefully turn the balance weight on the right side in a little, then it'll sit on zero regardless of the orientation... "R. Scott" wrote in message news:J2B3qt.68p@news.boeing.com... > > ------------ REPLY SEPARATOR ------------ > > > > 0 1 2 3 4 5 6 7 8 9 10 > > \ > > \ > > \ > > \ > > \ > > \ > > \ > > \ > > TROLL-O-METER > > > > > > Bill, W6WRT > > There I fixed it for you > > Article: 226432 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Antenna optimization Date: Wed, 12 Jul 2006 14:49:34 -0700 Message-ID: References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> On 12 Jul 2006 14:41:59 -0700, w0zv@yahoo.com wrote: >Brian's revenue flow is not being broken since he no longer has any >revenue flow from it. Hi Bill, This is NOT a defense against infringement. The author's rights are total, and the author's monopoly is total. There is nothing in the law that suspends those rights or monopoly even in the event of death of the author, so being out of the market place is a specious argument. This, and everything else you've had to offer may in fact be done, I see folks run red lights frequently too. >If you read his agreement carefully, it only >prohibits transfer of the software itself. I've read many agreements, but not this one. If you have a means to render it faithfully here, then perhaps so; otherwise those others I've read inform me better. 73's Richard Clark, KB7QHC Article: 226433 of rec.radio.amateur.antenna From: Ron Subject: FA: A KT34A was just listed on eBay for your information only. Date: 12 Jul 2006 17:52:33 EDT Message-ID: I guess I am not sure if eBay listing are approved on this list if they are not then let me know and I will not post on this group again. Being this is an antenna newsgroup and this is an antenna listing I figured some people might be interested. I just listed a new old stock KT34A on eBay. Please email me directly with your comments and question so as not to overpost on this group. Thanks Ron WA0KDS Article: 226434 of rec.radio.amateur.antenna From: "an old freind" Subject: Re: If you had to use CW to save someone's life, would that person die? Date: 12 Jul 2006 15:13:52 -0700 Message-ID: <1152742432.549280.204940@m79g2000cwm.googlegroups.com> References: <30954.oidi09.d0904.ddoi0@qkd.org> Dave wrote: > Cecil Moore wrote: > > C'mon Cecil, you've been licensed as long as I have. I Know you Know CW. Does > that mean we're virtually obsolete? not what make CW obseltete is that is out dated and all bu useless serious comms > GPS won't make a difference. Neither will CW today. meaning in light of the trolig title is useless > > I still enjoy CW. more power to you Article: 226435 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Antenna optimization Date: Wed, 12 Jul 2006 15:16:09 -0700 Message-ID: <12bat5ae09qe7d9@corp.supernews.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> I can't speak for Brian, but any output you produce from EZNEC is yours, and you can sell it or give it away as you wish. I think this is typical of software license agreements. Roy Lewallen, W7EL Richard Clark wrote: > On 12 Jul 2006 14:41:59 -0700, w0zv@yahoo.com wrote: > >> Brian's revenue flow is not being broken since he no longer has any >> revenue flow from it. > > Hi Bill, > > This is NOT a defense against infringement. The author's rights are > total, and the author's monopoly is total. There is nothing in the > law that suspends those rights or monopoly even in the event of death > of the author, so being out of the market place is a specious > argument. > > This, and everything else you've had to offer may in fact be done, I > see folks run red lights frequently too. > >> If you read his agreement carefully, it only >> prohibits transfer of the software itself. > > I've read many agreements, but not this one. If you have a means to > render it faithfully here, then perhaps so; otherwise those others > I've read inform me better. > > 73's > Richard Clark, KB7QHC Article: 226436 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 18:21:09 -0400 From: Dave Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> Message-ID: w0zv@yahoo.com wrote: Sorry, I lost the attribution trail. >>> >>>Why? The documentation says: >>> >>>************************************************************************ >>> This software is copyrighted. It has been provided to >>> you on the condition that you will not sell, rent, lend, give >>> away, or otherwise transfer the software to others. >>>************************************************************************ >>> SNIPPED >>Hi Bill, >> >>Strange as it may seem, yes you would be in violation. >> >>Copyright is the author's total monopoly to insure his revenue from >>his creation. If you disrupt that revenue flow you are breaking the >>law. You said it yourself, he doesn't market to amateurs - rather >>professionals who will pay for the LICENSE to use it professionally. >>If they choose to do someone a favor, and drop their fee, that is >>their hit, not his. He granted them the right, by LICENSE and at a >>cost, to lose money if they wish. > > There are two additional issues here. First, a registered copyright is valid for 55 years, it transcends death and becomes part of the copyright holder's estate. It can be renewed under specified conditions. So, going out of or changing business does not void the copyright. By law, the legal penalties begin at $100,000 per violation. Second, the principle of REASONABLE USAGE is applicable to copyrighted material. Example: I buy a Copyrighted CD for my personal usage. I am allowed to install an additional copy on my computer for my personal usage. I am allowed to install an additional copy on my MP3 player for my personal usage. All subject to the condition that only one copy will be used at any one time. This does not violate the copyright law and applicable precedents. Libraries are allowed to makes partial copies of copyrighted material. It is the REASONABLE PRESUMPTION that libraries provide data. Universities can make partial copies of copyrighted material for academic classroom and research usage. Etc. The legal burden for proof of REASONABLE USAGE rests with the individual or institution who purchases the license. Article: 226437 of rec.radio.amateur.antenna From: "Jerry Martes" References: <1152298653.803900.283720@s13g2000cwa.googlegroups.com> <1152726944.011458.76070@75g2000cwc.googlegroups.com> <1152732859.041808.322940@i42g2000cwa.googlegroups.com> Subject: Re: Reradiating RF signals from Satellital Modem Message-ID: Date: Wed, 12 Jul 2006 22:35:14 GMT wrote in message news:1152732859.041808.322940@i42g2000cwa.googlegroups.com... > > Jerry Martes ha escrito: > >> wrote in message >> news:1152726944.011458.76070@75g2000cwc.googlegroups.com... >> > >> > Jerry Martes ha escrito: >> > >> >> wrote in message >> >> news:1152298653.803900.283720@s13g2000cwa.googlegroups.com... >> >> > I'm to install a satellital modem (Globalstar GSP-1620) in a place >> >> > where there's no full direct sky visibility due to some metallic >> >> > obstacules. >> >> > To overcome this problem I'm thinking of placing a reradiating >> >> > antenna >> >> > or RF repeater over the top of the highest obstacule, facing the >> >> > real >> >> > GSP1620 antenna down on the ground. >> >> > >> >> > The GSP1620 has two RF frequencies, one for TX (1610-1625 Mhz) and >> >> > another for RX (2484-2499 Mhz). Does anyone have any ideas on how to >> >> > build up such reradiating antenna and/or RF repeater ? Is there any >> >> > commercial product similar to this ? >> >> > >> >> > Thanks a lot. >> >> > Pablo >> >> >> >> Hi Pablo >> >> >> >> I am curious about your globalstar instalation. What kind of >> >> antenna >> >> will >> >> you use at the location that "sees" the satellites? >> >> And, why is it *not* OK to use coax cable from the remote antenna to >> >> the >> >> telephone in the shadows? >> >> >> >> I am currently trying to build an antenna for Chris W. for his >> >> Globalstar >> >> satelite phone. >> >> >> >> Jerry >> > >> > Jerry, >> > >> > For the location that actually sees the satellites the antenna must be >> > an omnidirectional one ('cause globalstar constelation is LEO), perhaps >> > the one that comes with the GSP-1620 (check >> > http://www.globalstarusa.com/en/data/data_display.php?id=6). Since the >> > OEM modem will be on the ground and since I cannot use any coax cable >> > between them, I'm trying to find a wireless alternative, i.e. place an >> > omnidirectional antenna over the highest obstacule and forward/repeat >> > that RF signal down thru a directive antenna back to the ground where >> > another (to be build) directive antenna (to avoid multipath satellite >> > fixes) is attached to the modem. My question is about how to build such >> > forwarding/repeating RF device and the corresponding directive antenna >> > for both ends. >> > >> > Regards, >> > Pablo >> >> >> Hi Pablo >> >> The site you referanced implies that there is only one antenna supplied >> with this Globalstar GSP1620. Your text indicated that the GSP 1620 >> sends >> and receives signals on two widely seperated frequencies (1.62 GHz ans >> 2.4 >> GHz). >> Although I would like to know more about how the GSP 1620 works, this >> is >> probably not the right place for me to get educated. >> I'll be impresed if you manage to make dual frequency system work by >> using >> radiated RF to connect between a remote location and the Antenna. >> If there was any posibility that the entire Modum *and* Antenna could >> be >> located up at the location where the satellites can see it, you could >> (maybe) create a RF link between the GSP 1620 Modum and the remote >> location. >> >> Jerry > > That's correct, there's only one antenna that handles both frequencies. > In the bottom of the antenna you have two SMA connectors, one for TX > and other for RX. In case you are further interested in this modem and > its capabilities you can download the integrator's manual from > http://common.globalstar.com/doc/common/en/products/gsp1620_integrator_manual.pdf > > Well I certanly do hope to get around this problem, since I cannot > place both the modem and antenna in the same higher spot. > > Regards, > Pablo Hi Pablo By my standards, you have a problem that would be Very impractical to solve. You cant use coax from the antenna (located at the higher spot) to the modem. And you cant locate the modem at the higher spot, with the antenna. I would go so far as to state that there is No solution to your problem. If I had the obligation to demonstrate to you that the "higher spot" antenna idea wont work with your restrictions, I'd start with basic far field path loss. But, if you absolutely have to get that Globalstar GSP1620 working, I hope I'm wrong. Jerry Jerry Article: 226438 of rec.radio.amateur.antenna From: w0zv@yahoo.com Subject: Re: Antenna optimization Date: 12 Jul 2006 15:58:23 -0700 Message-ID: <1152745103.661683.249040@p79g2000cwp.googlegroups.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> Roy Lewallen wrote: > I can't speak for Brian, but any output you produce from EZNEC is yours, > and you can sell it or give it away as you wish. I think this is typical > of software license agreements. I agree Roy. The **software** is licensed...not its output. Brian's license agreement says absolutely nothing about output. Am I correct about Brian going into the audio business? Thought you might know. 73, Bill W4ZV Article: 226439 of rec.radio.amateur.antenna From: Jim - NN7K Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> Message-ID: Date: Wed, 12 Jul 2006 23:13:48 GMT Does this also include ALL Public Libraries (includeing the Library of Congress)?? Especially those that have Copying Machines? If so, then DON'T support them, BAN'em!! A thought-- Jim NN7K Yuri Blanarovich wrote: > Is this lawyertwist's interpretation? > Like it is not COPYright it is REVENUEright? > Don't you anybody ask to read my copyrighted magazine issue! You will > disrupt the revenue flow of the publisher/authors. Oh, and don't read any > magazines in your dentist's office while you are shaking for the treatment. Article: 226440 of rec.radio.amateur.antenna From: w0zv@yahoo.com Subject: Re: Antenna optimization Date: 12 Jul 2006 16:34:20 -0700 Message-ID: <1152747260.219160.151020@35g2000cwc.googlegroups.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> w0zv@yahoo.com wrote: > > Am I correct about Brian going into the audio business? Thought you > might know. Quick Google search resulted in the following. Not sure how Brian is making money on this but his head is clearly not into ham radio any longer. :-( http://users.tns.net/~bb/index.html 73, Bill W4ZV Article: 226441 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 18:35:54 -0500 From: Tom Ring Subject: Re: Warning: New Usenet ModeratorTo Shut Down Abusers IfNecesssary. References: <4n6ql.jaf.19.1@news.alt.net> <12b8k3ugq5ovgeb@corp.supernews.com> <44b45621$0$1016$39cecf19@news.twtelecom.net> Message-ID: <44b5875a$0$6154$39cecf19@news.twtelecom.net> Sal M. Onella wrote: > > Yes, but I think this was more an odd attempt to be funny. Suggest all go > back and look at whom he said he "will not hesitate to contact" ... then > decide how to take the OP. I bet he didn't mean to spin up so many people. > > No offense, but only an idiot wouldn't have known that they would "spin up" people on these news groups, or any others for that matter. Your idea is possible, but I'd have to say not probable. If what you say _is_ true, maybe he'll 'fess up. That would be interesting. tom K0TAR Article: 226442 of rec.radio.amateur.antenna From: ml Subject: boomless 'quad' ? Message-ID: Date: Wed, 12 Jul 2006 23:59:30 GMT not sure if i am really correctly describing a idea that came into my mind properly and hey it may be a 1/2 baked idea but i was trying to think of what might be a interesting experiment to take advantage of some unusual 'realestate' my building complex consists of several equal height and almost equially spaced buildings from one end to the other would be a few blocks long at least over 500ft n/s and going west about 1000ft (more like a t shape east is a big park (3000ackers) i was wondering if i could make a quad or somthing that each building would have a piece of thinking would eliminate the boom and i would end up with a antenna that might be very interesting on say 40 80 160 (&others) maybe i am wrong and end up w/marginal gain/performance anythoughts as to someone that might have constructed a simular experiment, if it might yeild me 'good gain' the idea of a quad arose, because i was thinking it'd offer more performance than say a really long dipole, w/the quad or so i could have many elements the idea of a beam came to mind too but i thought making many horizontal parts and interconnecting them may be harder the smallest 'gap' between buildings seems about 50ft any thoughts? Article: 226443 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> Subject: Re: Antenna optimization Message-ID: <85gtg.4014$2B3.1209@fe10.lga> Date: Wed, 12 Jul 2006 20:02:38 -0400 Back to antenna optimization, modeling software is a great tool and can save a lot of tinkering with hardware in the freezing nights, but has to be taken with a grain of salt. I treat it as a "bring me into the ballpark" tool, rather than "gospel". K6STI did great job with his YO and AO and W4ZV used it to optimize his KLM stacks very closely. I tried it on my 3 el. Quad design, which was originally designed on the 2m antenna test range and then scaled to HF bands, which worked quite well, within 50 kHz in resonant frequencies. When I tried to make it better by sticking it into optimization software, the software made it better, on paper. When I readjusted the dimensions accordingly, thing was off and worse than before. Maybe software did not capture the color of spreaders. There are still some parameters that modeling does not capture 100% and I am always taking the modeling results with grain of salt. There is whole "industry" of antenna "designers" doing it on models and proclaiming as gospel. Reality is sometimes cruel and doesn't care what the model says, especially when considering the environment in which antennas are to operate. Just caution not believe 100% blindly what the model says, as we saw in case of loading coils. I love the free space designs :-) YO, AO, MMANA, 4NEC2 are great tools and to see how good they are, just let them optimize the same design and see how close they get within each other. Sorry to see Brian, K6STI quit producing ham stuff, but I do not blame him. I was in the similar situation, developed Cyrillic languages support for desktop publishing, sold few dozen copies, only to find that there were hundreds if not thousands in use from Praha to Vladivostok. I can see my stamp in the fonts files all over the world. So I quit producing the software and let the Microsoft carry on, now it is built into Windoze. 73 Yuri, K3BU "Jim - NN7K" wrote in message news:Mmftg.171403$F_3.22153@newssvr29.news.prodigy.net... > Does this also include ALL Public Libraries (includeing the Library of > Congress)?? > Especially those that have Copying Machines? > > If so, then DON'T support them, BAN'em!! > A thought-- Jim NN7K > > > Yuri Blanarovich wrote: >> Is this lawyertwist's interpretation? >> Like it is not COPYright it is REVENUEright? >> Don't you anybody ask to read my copyrighted magazine issue! You will >> disrupt the revenue flow of the publisher/authors. Oh, and don't read any >> magazines in your dentist's office while you are shaking for the >> treatment. Article: 226444 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 19:37:11 -0500 From: Tom Ring Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> Message-ID: <44b595b8$0$1008$39cecf19@news.twtelecom.net> Richard Clark wrote: > > I've read many agreements, but not this one. If you have a means to > render it faithfully here, then perhaps so; otherwise those others > I've read inform me better. > > 73's > Richard Clark, KB7QHC Well, searching the documemtation of version 6.04, I can find only this in YO.DOC Copyright 1995 by Brian Beezley, K6STI All Rights Reserved Version 5.0 is not quite the same, this is from READ.ME, nothing in YO.DOC, or any other file Copyright and License This software is copyrighted. It is licensed for use by the purchaser only. Copies may not be sold, rented, leased, loaned, given away, or otherwise distributed. This copy is licensed for amateur use only. That's all there is in either version of YO that contains the "copyright" in any form, case insensitive. I am ignoring the companion programs. Interestingly, the .EXE files do not include a copyright notice internal to the program, at least in plain text. The only thing that shows when running the program (v6.x) is "Copyright 1995 by Brian Beezley, K6STI All Rights Reserved" at the top line on the files menu. I am writing the last from memory since it's a DOS program, so I might not have it perfect. tom K0TAR Article: 226445 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 19:44:46 -0500 From: Tom Ring Subject: Re: If you had to use CW to save someone's life, would that person References: <30954.oidi09.d0904.ddoi0@qkd.org> Message-ID: <44b5977e$0$1008$39cecf19@news.twtelecom.net> Dirk wrote: > Ham's care more about operating appliances than knowing how to save a lives. > > :-( > PLONK! tom K0TAR Article: 226446 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Wed, 12 Jul 2006 17:44:54 -0700 Message-ID: References: <30954.oidi09.d0904.ddoi0@qkd.org> ORIGINAL MESSAGE: On Wed, 12 Jul 2006 20:04:06 GMT, "R. Scott" wrote: >> ------------ REPLY SEPARATOR ------------ >> >> 1 2 3 4 5 6 7 8 9 10 >> \ >> \ >> \ >> \ >> \ >> \ >> \ >> \ >> TROLL-O-METER >> >> >> Bill, W6WRT > >There I fixed it for you > ------------ REPLY SEPARATOR ------------ I think you just unplugged your trolltenna. Bill, W6WRT Article: 226447 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 19:47:26 -0500 From: Tom Ring Subject: Re: If you had to use CW to save someone's life, would that person References: <30954.oidi09.d0904.ddoi0@qkd.org> Message-ID: <44b5981e$0$1008$39cecf19@news.twtelecom.net> R. Scott wrote: >>------------ REPLY SEPARATOR ------------ >> >> 1 2 3 4 5 6 7 8 9 10 >> \ >> \ >> \ >> \ >> \ >> \ >> \ >> \ >>TROLL-O-METER >> >> >>Bill, W6WRT > > > There I fixed it for you > > PLONK! There, I fixed it for me. tom K0TAR Article: 226448 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Antenna optimization Date: Wed, 12 Jul 2006 18:03:54 -0700 Message-ID: <12bb6vskrf58l28@corp.supernews.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> Tom Ring wrote: > > That's all there is in either version of YO that contains the > "copyright" in any form, case insensitive. I am ignoring the companion > programs. Interestingly, the .EXE files do not include a copyright > notice internal to the program, at least in plain text. The only thing > that shows when running the program (v6.x) is "Copyright 1995 by Brian > Beezley, K6STI All Rights Reserved" at the top line on the files menu. > I am writing the last from memory since it's a DOS program, so I might > not have it perfect. Under current U.S. law, a copyright notice isn't required in order to secure a copyright; the copyright automatically exists as soon as the work is created. Adding a copyright notice does bring some advantages if a lawsuit is filed, however. Disclaimer: I'm not an attorney. Roy Lewallen, W7EL Article: 226449 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 20:30:41 -0500 From: Tom Ring Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> <12bb6vskrf58l28@corp.supernews.com> Message-ID: <44b5a241$0$6145$39cecf19@news.twtelecom.net> Roy Lewallen wrote: > > Under current U.S. law, a copyright notice isn't required in order to > secure a copyright; the copyright automatically exists as soon as the > work is created. Adding a copyright notice does bring some advantages > if a lawsuit is filed, however. > > Disclaimer: I'm not an attorney. > > Roy Lewallen, W7EL I am only passing along what I have found. I have no dog in this fight, hihi. tom K0TAR Article: 226450 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 21:43:36 -0400 From: John Popelish Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> <12bb6vskrf58l28@corp.supernews.com> <44b5a241$0$6145$39cecf19@news.twtelecom.net> Message-ID: Tom Ring wrote: (snip) > I have no dog in this fight, hihi. Tom, please define "hihi" in this context. Thank you. Article: 226451 of rec.radio.amateur.antenna Subject: Re: If you had to use CW to save someone's life, would that person die? From: Dave Oldridge References: <30954.oidi09.d0904.ddoi0@qkd.org> Message-ID: Date: Thu, 13 Jul 2006 01:50:13 GMT dj@qkd.net (Dirk) wrote in news:30954.oidi09.d0904.ddoi0@qkd.org: > Ham's care more about operating appliances than knowing how to save a > lives. The person would not die on my watch, as long as I could get a signal out and someone on the other end could copy it. I'd probably have to practice a bit to get back up over 50wpm, but I can do 25 or 30 all day long. -- Dave Oldridge+ ICQ 1800667 Article: 226452 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Antenna optimization Date: Wed, 12 Jul 2006 18:48:42 -0700 Message-ID: References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> On Wed, 12 Jul 2006 19:37:11 -0500, Tom Ring wrote: >That's all there is in either version of YO that contains the >"copyright" in any form, case insensitive. I am ignoring the companion >programs. Hi Tom, Pretty unsophisticated, certainly. This redoubles my experience with other licensing as being far more exclusive. However, with five patents of my own, I can certainly attest that these scraps offer protection that have all the muscle of paper. These ego certificates allow you to get past a lawyer's secretary and spend money trying to convince judges with the technically savvy of troglodytes. Franklin was right about these matters. As for automated optimization, NASA spent huge bucks on this stuff to design twisted paper clips to replace Walt's work of 30 years ago. I can well bet that license runs pages. If the testimonials to Beezley are any indicator, the utility of the software is in inverse proportion to the length of its license. 73's Richard Clark, KB7QHC Article: 226453 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 20:56:38 -0500 From: Tom Ring Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> <12bb6vskrf58l28@corp.supernews.com> <44b5a241$0$6145$39cecf19@news.twtelecom.net> Message-ID: <44b5a856$0$6145$39cecf19@news.twtelecom.net> John Popelish wrote: > Tom Ring wrote: > (snip) > > I have no dog in this fight, hihi. > > Tom, please define "hihi" in this context. Thank you. > hihi, CW for laughter. Lots of dits in a row. Meant I am amused by the whole thing. Do you need more explanation, or was that adequate? tom K0TAR Article: 226454 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 22:12:48 -0400 From: John Popelish Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> <12bb6vskrf58l28@corp.supernews.com> <44b5a241$0$6145$39cecf19@news.twtelecom.net> <44b5a856$0$6145$39cecf19@news.twtelecom.net> Message-ID: Tom Ring wrote: > John Popelish wrote: > >> Tom Ring wrote: >> (snip) >> > I have no dog in this fight, hihi. >> >> Tom, please define "hihi" in this context. Thank you. >> > > hihi, CW for laughter. Lots of dits in a row. Meant I am amused by the > whole thing. > > Do you need more explanation, or was that adequate? Perfectly adequate. Thank you. I have seen this a lot, lately, and didn't know its meaning. Article: 226455 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 21:16:29 -0500 From: Tom Ring Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> Message-ID: <44b5acfd$0$6145$39cecf19@news.twtelecom.net> Richard Clark wrote: > As for automated optimization, NASA spent huge bucks on this stuff to > design twisted paper clips to replace Walt's work of 30 years ago. I > can well bet that license runs pages. If the testimonials to Beezley > are any indicator, the utility of the software is in inverse > proportion to the length of its license. > > 73's > Richard Clark, KB7QHC However some of it does work very well. YO, when used correctly can just barely beat K1FO's designs, which were done on a PDP11, using a special version of BASIC, as I remember from conversations with him long ago. He got the designs as right as possible, using an EME'rs version of right. He hit max gain for boomlength within less than 1dB, pattern is wonderful, SWR BW is astonishing, and pattern and gain are all fairly constant across the usable SWR BW. Input impedance is not too low, at about 20-25 ohms, and efficient match can be had with a T-match. And it handles ice and rain detuning perfectly. Build sensitivity is nice; you can skew the design by induced errors of +-2mm element length and +-5mm vertical off the boom and +-2mm element position on the boom with no significant change. Gain not off by .1dB, pattern not off by 2dB, normally less. I ran a lot of tests. And I could be misremembering a bit, but probably by too high rather than too low. And YO could beat K1FO by only hudredths of a dB. If he'd had more CPU power to do more runs per day... tom K0TAR Article: 226456 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 21:21:04 -0500 From: Tom Ring Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> Message-ID: <44b5ae10$0$6145$39cecf19@news.twtelecom.net> Richard Clark wrote: > As for automated optimization, NASA spent huge bucks on this stuff to > design twisted paper clips to replace Walt's work of 30 years ago. I > can well bet that license runs pages. If the testimonials to Beezley > are any indicator, the utility of the software is in inverse > proportion to the length of its license. > > 73's > Richard Clark, KB7QHC I forgot to mention that the K1FO designs referred to were at 432. tom K0TAR Article: 226457 of rec.radio.amateur.antenna Date: Wed, 12 Jul 2006 21:23:42 -0500 From: Tom Ring Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> <12bb6vskrf58l28@corp.supernews.com> <44b5a241$0$6145$39cecf19@news.twtelecom.net> <44b5a856$0$6145$39cecf19@news.twtelecom.net> Message-ID: <44b5aeae$0$6145$39cecf19@news.twtelecom.net> John Popelish wrote: > > > Perfectly adequate. Thank you. > > I have seen this a lot, lately, and didn't know its meaning. As a Syrius Cybernetics construct would say "Glad to be of service!" tom K0TAR Article: 226458 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Antenna optimization Date: Wed, 12 Jul 2006 20:04:34 -0700 Message-ID: References: <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> <44b5acfd$0$6145$39cecf19@news.twtelecom.net> On Wed, 12 Jul 2006 21:16:29 -0500, Tom Ring wrote: >He got the designs as right as possible, using an EME'rs version of >right. He hit max gain for boomlength within less than 1dB, pattern is >wonderful, SWR BW is astonishing, and pattern and gain are all fairly >constant across the usable SWR BW. Input impedance is not too low, at >about 20-25 ohms, and efficient match can be had with a T-match. And it >handles ice and rain detuning perfectly. Build sensitivity is nice; you >can skew the design by induced errors of +-2mm element length and +-5mm >vertical off the boom and +-2mm element position on the boom with no >significant change. Gain not off by .1dB, pattern not off by 2dB, >normally less. I ran a lot of tests. And I could be misremembering a >bit, but probably by too high rather than too low. Hi Tom, This is all pretty significant stuff. Its success probably ties in with what Reggie had to say about the quality of automated software being tied to the competence of the user/designer (Reggie may wish to distance himself from my paraphrase however). As a negative example, some half decade or more ago we had a fractal designer who threw as much computational horsepower at this as his budget would allow in hiring eager, bright faced graduates building parallel processors. They perhaps knew Genetic Algorithms (the hot topic in academia whose bloom had long faded in cut-throat industry), but certainly nothing about the bajillion degrees of freedom in antenna design. Well, that stack of computers was more a marketing paper weight than a design producer - I've never seen an independent headline announcing the dawn of a new age of fractals in Boston. In fact, it would seem that same NASA program stole their thunder - and it is still a yawn. 73's Richard Clark, KB7QHC Article: 226459 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: Antenna optimization Date: Wed, 12 Jul 2006 23:12:20 -0400 Message-ID: <12bbedm11d1eubd@corp.supernews.com> References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> <12bb6vskrf58l28@corp.supernews.com> Dear Roy and the group: As you know, my other job is that of a patent attorney. It is time to comment. We are not concerned with patents. It is common to overlap patent protection of something useful with copyright protection of an expression. This is more common when software is involved because a patent might involve software and Congress has made it clear that software is amiable of copyright protection. As you have observed, a copyright notice is no longer required. However, I always tell clients to provide such a notice. Judges, most reasonably, may wonder why a notice was not provided when to do so costs (in most cases) nothing and the absence of a notice can cause mischief. The requirement not to require notices was due to pressure from European interests. If one thinks one will need to defend one's copyright, it is beneficial to register the copyright with the Copyright Office (part of the Library of Congress) - a simple process. Let us turn to what copyright is: it is the right to prevent the making of copies of a work by others. One who holds a copyright to a work has the right to control copies of that work. Congress and the courts have carved out some exceptions. We have seen one used here where one copies small sections of a copyrighted book or paper. Researchers and universities are given some narrow rights to copy the works of others. In a law suit, an important aspect is the degree that someone's unauthorized copying has actually injured the copyright owner. Absent a specific contract to the contrary, one who legally purchases a copyrighted work may sell it, destroy it, read it if it can be read, and run it on a computer if it is software. Such a lawful copy may be used to facilitate the crafting of another work (such as using WordPerfect to write a letter) or may be used to facilitate the fabrication of useful articles (such as the use of EZNEC to design an antenna that is improved in some way). Let us keep patent protection and copyright protection in their separate cages. To the issue of the French radio amateur who started this long string (and with a nod to the opinion of the experienced radio amateur in the UK): optimization of more than simple antennas still requires the intersession of a thoughtful and experienced human. My experience has been that the human's main contribution relates to crafting an adaptive notion of what optimum is, for the subject antenna. In other words: knowing when further playing is not appropriate. 73, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Roy Lewallen" wrote in message news:12bb6vskrf58l28@corp.supernews.com... > Tom Ring wrote: > > > > That's all there is in either version of YO that contains the > > "copyright" in any form, case insensitive. I am ignoring the companion > > programs. Interestingly, the .EXE files do not include a copyright > > notice internal to the program, at least in plain text. The only thing > > that shows when running the program (v6.x) is "Copyright 1995 by Brian > > Beezley, K6STI All Rights Reserved" at the top line on the files menu. > > I am writing the last from memory since it's a DOS program, so I might > > not have it perfect. > > Under current U.S. law, a copyright notice isn't required in order to > secure a copyright; the copyright automatically exists as soon as the > work is created. Adding a copyright notice does bring some advantages > if a lawsuit is filed, however. > > Disclaimer: I'm not an attorney. > > Roy Lewallen, W7EL Article: 226460 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Voltage feeding a VHF yagi References: <1152233762.848358.152070@s13g2000cwa.googlegroups.com> <1152578671.148819.275420@b28g2000cwb.googlegroups.com> <1152609823.761832.13220@p79g2000cwp.googlegroups.com> <1152631289.594334.34440@m73g2000cwd.googlegroups.com> <1152643960.102707.230980@35g2000cwc.googlegroups.com> <1152645952.257578.20580@h48g2000cwc.googlegroups.com> <1152651970.397776.294700@35g2000cwc.googlegroups.com> <1152657212.158640.43920@h48g2000cwc.googlegroups.com> <1152736765.706079.169140@p79g2000cwp.googlegroups.com> Message-ID: Date: Thu, 13 Jul 2006 03:13:47 GMT w8ji@akorn.net wrote: > Cecil Moore wrote: >> The half-wave end-fed antenna starts at point X. The feedline is >> at point B. Here's what you said: >> >> w8ji@akorn.net wrote: >> > 1.) You have a half-wave end-fed antenna. There has to be as much >> > common mode current leaving the end of that point and flowing down the >> > feedline as there is flowing out onto the antenna at that point. There >> > isn't any exception to this rule. > > The STUB is a balanced transmission line. If you quoted the entire post > everyone would see what I meant. That is a complete quote of your item number 1. What you said is self explanatory. You said the current flowing onto the antenna is equal to the current flowing down the feedline. You were wrong. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226461 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: If you had to use CW to save someone's life, would that person References: <30954.oidi09.d0904.ddoi0@qkd.org> <12bactjanpufjfc@corp.supernews.com> Message-ID: Date: Thu, 13 Jul 2006 03:19:13 GMT Dave wrote: > C'mon Cecil, you've been licensed as long as I have. I Know you Know CW. > Does that mean we're virtually obsolete? My favorite mode is CW and it's a fun mode but it is never going to save the world. -- 73, Cecil http://www.qsl.net/w5dxp Article: 226462 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Antenna optimization References: <44b3afc1$0$990$ba4acef3@news.orange.fr> <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> <12bb6vskrf58l28@corp.supernews.com> <44b5a241$0$6145$39cecf19@news.twtelecom.net> <44b5a856$0$6145$39cecf19@news.twtelecom.net> Message-ID: Date: Thu, 13 Jul 2006 03:28:17 GMT Tom Ring wrote: > hihi, CW for laughter. hii hii, the beginning of the Texas Aggie war hymn. "Hullabaloo, Caneck! Caneck! Hullabaloo, Caneck! Caneck!" -- 73, Cecil http://www.qsl.net/w5dxp Article: 226463 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Antenna optimization Message-ID: References: <44b3d3d0$0$819$ba4acef3@news.orange.fr> <1152639085.369972.127940@m79g2000cwm.googlegroups.com> <1152650749.420397.51760@m73g2000cwd.googlegroups.com> <1152740519.671520.212240@p79g2000cwp.googlegroups.com> <44b595b8$0$1008$39cecf19@news.twtelecom.net> <12bb6vskrf58l28@corp.supernews.com> <12bbedm11d1eubd@corp.supernews.com> Date: Thu, 13 Jul 2006 03:44:28 GMT On Wed, 12 Jul 2006 23:12:20 -0400, "J. Mc Laughlin" wrote: > Absent a specific contract to the contrary, one who legally purchases a >copyrighted work may sell it, destroy it, read it if it can be read, and run >it on a computer if it is software. Such a lawful copy may be used to >facilitate the crafting of another work (such as using WordPerfect to write >a letter) or may be used to facilitate the fabrication of useful articles >(such as the use of EZNEC to design an antenna that is improved in some >way). Mac, I am not sure of you meaning of a "specific contract". It is often the case that we acquire software (being a copyright work) under a licence that is an agreement between the licensor and the licensee. The agreement may be in the form of a general license, for instance an end user licence that the user is deemed to have accepted in using the software, or it could be in the form of a specific formal agreement executed by the parties. That agreement may limit the licensee's rights, including the purpose for which software is used. I give an example, the BestOne mainframe performance evaluation suite licence limited it use to execution a specific computer and explicitly only for analysis of performance data collected from that computer. Isn't the license agreement like any contract in that the parties can agree to anything lawful. It seems to me that one has to read the relevant licence agreement to form a view on what is or isn't permitted by the licence in addition to any rights under copyright statutes. Owen --