Article: 221436 of rec.radio.amateur.antenna From: "hasan schiers" Subject: Re: Why did this work (160m antenna)? Date: Wed, 1 Feb 2006 15:04:57 -0600 Message-ID: References: Hi Chuck, The lawn staples are from DX Engineering (as was the beautiful radial plate with bulkhead coax connector). They are about 6 inches long, a rectangle, maybe 1 inch wide, and heavy enough that you can pound them in with a hammer, as long as your soil isn't concrete. Sold in packages of 10 or 20, I think. Quite reasonably priced. I only have one staple per wire now (doing it in the middle of winter made me move quickly between ice and mud patches). I'll put down a staple every 10' or so when things dry out. Google DX Engineering and you will find there web site. From there it's pretty easy to find stuff. 73, ...hasan, N0AN Article: 221437 of rec.radio.amateur.antenna From: "Bryan Martin" Subject: 802.11 link Message-ID: Date: Wed, 01 Feb 2006 21:25:48 GMT I am attempting to setup a 802.11b bridge between my location (siteA) down the powerlines but off to the right NLOS (siteB) roughly 1 mile away. Now their is nothing between the powerline and siteB except it is off the powerlines to the right by about 20-40 feet. No trees, hills or any other unforeseen obstacles other than I simply cant see it due to the location. I guess the easy way to explain the setup is picture a L. I have successfully been able to broadcast my signal in reverse from siteA down the powerline even further than siteB but it was a strait shot and also was NLOS due to a house being directly in front. This was using a 24db parabolic grid antenna. My question and what I am trying to get my head around is if I could get by with just a standard wireless router without any external addon or booster antenna at siteB. Common sense tells me that even though its shaped similar to a L as long as the signal coming off siteB is present at the end of the powerline then I should be able to pick it up from the grid antenna. I plan on trying it this weekend but I am hoping someone can elaborate on this before I get my hopes up to much. -- Poor planning on your part does not constitute an emergency on my part. Article: 221438 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: New program - Antenna Counterpoise. Date: Thu, 2 Feb 2006 02:05:43 +0000 (UTC) Message-ID: A coil-loaded counterpoise at a low height above ground is used to provide an artificial ground for an antenna when, for some reason, a true ground connection is not possible or there is not enough space to erect a full 1/4-wavelength horizontal wire. The principal effects of low height are a loss resistance induced in the wire from the ground, and a reduction in propagation velocity along the wire. A counterpoise can be considered to be an artificial ground. Its input resistance at resonance is equivalent to the input resistance of a true ground connection but its resistance will never be as low as a good ground. To provide a lower input resistance three or four counterpoises can be used in parallel. Or they can be resonant on different bands. New program C_POISE estimates the performance of a single coil-loaded counterpoise. The number of turns on a coil of given length and diameter needed to resonate a low wire to 1/4-wave resonance is calculated. The input resistance at resonance is also estimated.. All program output data is approximate due to the very low height of the wire above ground and uncertainty in the characteristics of the soil or whatever other materials may be under the wire. The wire may be allowed to rest on the ground surface but uncertainty will be at a maximum. It will nearly always be needed to prune the wire length for resonance. Or when the wire length is fixed the coil turns may need adjustment. When wire height exceeds wire length accuracy is much improved. Input resistance at resonance will be fairly small. Working Q will be high and the counterpoise will behave as a short antenna. For precise resonance the wire will still need pruning. Download program C_POISE in a few seconds from website below and run immediately. ---- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 221439 of rec.radio.amateur.antenna Subject: Antenna for Rock-Mite From: Tod Glenn Date: Wed, 01 Feb 2006 19:59:38 -0700 Message-ID: Greetings all. I am interested in suggestions for a compact and portable antenna for my Rockmite 40m QRT xceiver. Something I can pack easily is ideal, optimized for 7.040. Besides the baside wire dipole, anyone have some suggestions? ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 221440 of rec.radio.amateur.antenna From: David Subject: Missed information on plane antenna Message-ID: <07YBf.227215$V7.136542@news-server.bigpond.net.au> Date: Thu, 26 Jan 2006 04:21:16 GMT Opps, should have mentioned, dipole is set off from plane 56mm using nylon insulators. Article: 221441 of rec.radio.amateur.antenna Subject: Re: external wifi antennas in laptops From: Date: Thu, 26 Jan 2006 10:43:37 GMT Message-ID: References: <11tgd1g2hb4s970@corp.supernews.com> Dave Platt, well I never... your sister Sarah, bit young for kids,,, nice though, in a whiny sort of way. Quick tip... leave a roller skate on the stairs to put Phil out of 'the picture for a while. I love seeing your mum Gail cry, such fun... Article: 221442 of rec.radio.amateur.antenna From: dplatt@radagast.org (Dave Platt) Subject: Re: Mobile installation question Date: Fri, 27 Jan 2006 05:33:02 -0000 Message-ID: <11tjc4ef0sh65de@corp.supernews.com> References: <06KdnXmGUdGV3UTeRVn-uQ@comcast.com> <11tiia21u8voh0b@corp.supernews.com> In article , John Popelish wrote: >Dave Platt wrote: > >> You'd be somewhat better off running the power-ground wire all the way >> back to the battery, and connecting directly to the battery's negative >> post. Include a fuse in this line just before it connects to the >> battery negative. >Why would that be the best arrangement? No steady state power comes >from the battery. If you want the least voltage drop, you take a pair >of wires back to the alternator, where the power originates. The >only advantage of the battery connection might be lower alternator >rectifier noise in the power, but that is pretty easy to filter out >right at the alternator, before it gets out in the wiring harness and >into the antenna. I've never heard of anyone hooking up auxiliary loads right at the alternator. I can imagine somebody hooking a secondary-battery feed at this point (in an RV, perhaps) but I don't think I've ever seen radios hooked up there. I rather strongly suspect that you'd find the amount of "alternator whine" in the audio to be significant greater if you hook up the radio right at the alternator. Every mobile-ham-radio installation guide I've ever read (including the owners' manuals) seems to recommend running heavy wires back to the battery. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! Article: 221443 of rec.radio.amateur.antenna From: Brian Howie Subject: Re: New 4nec2 version Date: Thu, 26 Jan 2006 07:46:15 +0000 Message-ID: References: <1138119779.443881.171030@g49g2000cwa.googlegroups.com> In message <43D82AEB.1020009@comcast.net>, dansawyeror writes >All, > >Has anyone tried this successfully? If so what OS and level did you >use? I tried, the installation went issue however attempts to execute >the app result in an error: 50003. > >Has anyone successfully gotten this to work? It runs correctly under W2000 here. Brian GM4DIJ -- Brian Howie Article: 221445 of rec.radio.amateur.antenna From: fmmck@aol.com (Fred McKenzie) Subject: Re: 802.11 link Date: Wed, 01 Feb 2006 22:27:51 -0500 Message-ID: References: In article , "Bryan Martin" wrote: > My question and what I am trying to get my head around is if I > could get by with just a standard wireless router without any external addon > or booster antenna at siteB. Common sense tells me that even though its > shaped similar to a L as long as the signal coming off siteB is present at > the end of the powerline then I should be able to pick it up from the grid > antenna. Bryan- I don't think the power line has anything to do with your signal. One technique that has been used to get around corners, is use of a passive reflector (metal grid?), sometimes called a "billboard". It is a lossy method, but not nearly as bad as what you seem to be trying to do! The structures between sites may not block all signals. With 24dB at each end, there might be enough signal to complete the link if two parabolic antennas were pointed at each other. Your greatest chance of success would be to erect a mast at each end, and mount the parabolic antennas high enough to shoot line-of-sight above any obstacles. How do you measuring success? One program that works with a wireless card, is called Stumbler. (I have the Macintosh version.) It detects wireless hotspots, and gives an indication of signal strength. Fred Article: 221446 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: 802.11 link References: Message-ID: Date: Thu, 02 Feb 2006 10:01:50 -0600 Hi Bryan I'd try and model this for you but the s/w I use is broken at the moment. You can calculate path loss over an LOS path fairly easily. If you start with the RF output in dBm, add antenna gains, subtract the path and cable losses you'll get a close result. This can then be applied against the receiver sensitivity (I use to use -87dBm for 802.11 links) If you want to model in the existence of a reflector or (say) back to back yagi you do it is two paths using the received power at the reflecting device as the source power for the next minus about 3dB. The results tend to be less than encouraging in most places but it depends on the application. One study I did (for example) was to get a 410MHz signal into a railway cutting on the edge of a mountain. (ie no source of reflection from the other side) The 25W TX was about 2km away and we modeled two back to back 13dBi antennas. With -82dBm as the lowest specd RX signal we only got about 300m range from the reflecting array. Freds suggestion of using a billboard is however a good one and simple to experiment with. I also agree that the powerline wont be much help. Pls tell us how it works out! Cheers Bob VK2YQA Bryan Martin wrote: > I am attempting to setup a 802.11b bridge between my location (siteA) down > the powerlines but off to the right NLOS (siteB) roughly 1 mile away. Article: 221447 of rec.radio.amateur.antenna From: "johan aeq" References: Subject: Re: Antenna for Rock-Mite Date: Thu, 2 Feb 2006 17:43:49 +0100 Message-ID: buy a fishing rod and hang up a inverted v. If you feed it with 300Ohm line or even loudspeaker cable you don't need a balun up the rod. Match it with a 1:1 balun or a simple Zmatch (emtech). It works simple and very good... "TSnCS" schreef in bericht news:X_ednTlxy54ckn_enZ2dnUVZ_sudnZ2d@comcast.com... > If it's QRT, do your really need an antenna?? (Sorry, couldn't resist) > > > "Tod Glenn" wrote in message > news:webmaster-5918D5.19593701022006@news.usenet-access.com... > > Greetings all. > > > > I am interested in suggestions for a compact and portable antenna for my > > Rockmite 40m QRT xceiver. Something I can pack easily is ideal, > > optimized for 7.040. Besides the baside wire dipole, anyone have some > > suggestions? > > > > > > ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet > > News==---- > > http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 > > Newsgroups > > ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- > > Article: 221448 of rec.radio.amateur.antenna From: "Bryan Martin" References: Subject: Re: 802.11 link Message-ID: Date: Thu, 02 Feb 2006 19:07:28 GMT Well the downside is that I dont think I can pull off the reflector senerio or complete line of site going over the tree's. At the end of this powerline is someone else's lot so I can't place anything on or around that. I only have permission to put the unit in the building located behind someone's house. Ideally I would rather not have any external antenna's on the building if at all possible to make the intrusion on property as light as possible. Thats what brought me to my question. The building is just an old cheap yard shed more than anything. It has power and 2 windows on the back side facing the back of the lot. I hope to be able to place the wireless unit close to the window which should help push the signal. If the building was another 25-30 foot more to the right I might would have LOS to it but that is also when you cross over onto someone elses land which is not an option. As for seeing the signal I am almost completely positive the grid antenna would be able to intersect the wireless signal at the end of the powerline but I am unsure if that is enough to get the signal back? To see a very rough layout of what I am refering to see this http://home.triad.rr.com/tempdir/images/layout.jpg "Bob Bob" wrote in message news:e0n9b3-r7l.ln1@p400bob.personal.cox.net... > Hi Bryan > > I'd try and model this for you but the s/w I use is broken at the moment. > > You can calculate path loss over an LOS path fairly easily. If you start > with the RF output in dBm, add antenna gains, subtract the path and cable > losses you'll get a close result. This can then be applied against the > receiver sensitivity (I use to use -87dBm for 802.11 links) If you want to > model in the existence of a reflector or (say) back to back yagi you do it > is two paths using the received power at the reflecting device as the > source power for the next minus about 3dB. The results tend to be less > than encouraging in most places but it depends on the application. One > study I did (for example) was to get a 410MHz signal into a railway > cutting on the edge of a mountain. (ie no source of reflection from the > other side) The 25W TX was about 2km away and we modeled two back to back > 13dBi antennas. With -82dBm as the lowest specd RX signal we only got > about 300m range from the reflecting array. > > Freds suggestion of using a billboard is however a good one and simple to > experiment with. I also agree that the powerline wont be much help. > > Pls tell us how it works out! > > Cheers Bob VK2YQA > > Bryan Martin wrote: >> I am attempting to setup a 802.11b bridge between my location (siteA) >> down >> the powerlines but off to the right NLOS (siteB) roughly 1 mile away. Article: 221449 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Verticals versus Horizontal Dipoles Date: Fri, 3 Feb 2006 03:36:26 -0600 Message-ID: <476-43E3241A-1@storefull-3255.bay.webtv.net> References: Reg, G4FGQ wrote: "On the other hand, a simple vertical does reasonably well when working just across country because of the short propagation path, almost straight up and down again, even via the groundwave for a very short distance." True, but the thread is: "Verticals versus Horizontal Dipoles". Reg`s choice, I think. Verticals have a null toward the zenith which tends to impair their "straight up and down again" performance. The horizontal dipole`s nulls are at its tips, too, but are pointed elsewhere, not at the zenith. This mey actually avoid some noise and interference beyond that originating in the directions of straight up or down again. As much noise is vertically polarized, it may be rejected by ctoss-polarization. The horizontal dipole performs pretty well in the directions near the zenith when it is elevated at less than 1/2-wavelength in height, and for frequencies below the maximum usable frequency at near vertical incidence. At 1/2-wavelength elevation, the horizondal dipole develops a null toward the zenith, too. Propagation of H-F signals via the groundwave is for a very short distance indeed. Frequency has a pronounced effect upon sffective earth conductivity. Conductivity falls fast with increasing frequency due to skin effect. . The earth layer penetrated by the wave thins as frequency increases, making it less conductive and increases loss. For example, over soil of 10 mmhos/m, a fairly common value, a transmitter would have to ptoduce 1,000 times more power at 5 MHz to produce the same signal at 10 miles as would a 0.5 MHz transmitter. The earth`s attenuation of low-angle radiation from a 1/4-wave vertical antenna has a significant effect on the vertical radiation pattern. ee Fig. 54-1 on page 465 of B. Whitfield Griffith`s "Radio-Electronic Transmission Fundamentals". This figure shows field intensity curves versus vertical angle from a 1/4-wave vertical antenna radiating 1 kilowatt over earth of average conductivity. Anything below about 5-degrees is gone, eaten by the earth`s losses. I conclude that for high frequencies, unless you have good or very good conductivity soil, horizontal polarization will likely serve you better than vertical polarization. If you are at sea or immediately on the sea shore, you likely may do better with vertical polarization. There are so many variables that it would likely be best to have antennas of both polarizations available, and to use the antenna which gave the best signal in the particular instance. Best regards, Richard Harrison, KB5WZI Article: 221450 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: New program - Antenna Counterpoise. Date: Fri, 3 Feb 2006 10:06:16 +0000 (UTC) Message-ID: References: > Reg , What is your opinion about the effectiveness of (a) counter poise(s) > of any length in series with an adjustable series resonance circuit > ,adjusted for maximum RF current at the operating frequency ? > Frank GM0CSZ / KN6WH =========================================== Frank, the effectiveness of a counterpoise depends on its input resistance. The lower this resistance better it is. It is the 'ground' connection for the antenna. (And the transmitter). But there's no point in making it longer than 1/4-wave. This increases coupling with the ground, increases loss resistance and also undesirably increases radiation resistance. The counterpoise then behaves more like a very low antenna. When it is 1/2-wavelength long it has a very high input resistance and is entirely non-effective. It may just as well not be there. At some lengths the loading coil would have to be replaced with a loading capacitor. Remember, the antenna wire plus counterpoise is behaving as an off-centre fed, bent, dipole with the lower section being very near to the lossy ground. (Whatever the ground is). We don't want the lower section to be TOO long. The current into the counterpoise is the same current as is entering the antenna. If there is an antenna tuning unit it will tune up the counterpoise simultaneously with the antenna. They behave together as one thing! So there is no point in having a separate tuner just for the counterpoise. Maximum current flows into the counterpoise at the same time as it flows into the antenna proper. The purpose of the loading coil in the counterpoise is to provide a low impedance connection to the braid of the coaxial feedline. If there is no feedline then it provides an artificial 'ground' for the transmitter plus tuner. And all the foregoing arises because it is difficult or impossible for the station owner to provide a set of buried ground radials. ---- Reg, G4FGQ Article: 221451 of rec.radio.amateur.antenna From: "Richard Fry" References: <476-43E3241A-1@storefull-3255.bay.webtv.net> Subject: Re: Verticals versus Horizontal Dipoles Date: Fri, 3 Feb 2006 07:00:32 -0600 Message-ID: <43e3532e_1@newsfeed.slurp.net> "Richard Harrison" wrote: > The earth`s attenuation of low-angle radiation from a 1/4-wave vertical > antenna has a significant effect on the vertical radiation pattern. ee > Fig. 54-1 on page 465 of B. Whitfield Griffith`s "Radio-Electronic > Transmission Fundamentals". This figure shows field intensity curves > versus vertical angle from a 1/4-wave vertical antenna radiating 1 > kilowatt over earth of average conductivity. Anything below about > 5-degrees is gone, eaten by the earth`s losses. ________________ This certainly is not true for frequencies below about 2 MHz. If it was true, MW broadcast stations would have no groundwave coverage -- which of course is the only useful coverage they _do_ have in the daytime. A monopole vertical radiator of any length up to 5/8-wave, when used with a ground system of ~120 buried radials each ~1/2-wave long, radiates its peak field very nearly in the horizontal plane regardless of the conductivity of the ground in which the radials are buried. This gain is within a few percent of the theoretical peak gain for these radiators when working against an infinite, perfectly conducting ground plane, as was demonstrated by the field tests of Brown, Lewis & Epstein in 1937. This principle has been accepted and used by the FCC and other regulating agencies, and has been field-proven in thousands of installations going back many decades. Once "launched," the groundwave signal is affected by ground conductivity along the propagation path, earth curvature, obstructions etc. Groundwave path loss increases with increasing frequency, and above some frequency in the low HF range, the groundwave is unable to serve a practical purpose. But that doesn't necessarily mean that the transmit antenna did not generate the groundwave in the first place, ie, that it radiated zero field in the horizontal plane and at very low elevation angles. RF Visit http://rfry.org for FM transmission system papers. Article: 221452 of rec.radio.amateur.antenna Subject: Re: Pulley Arrangement For Horiz. Antenna ? From: "Doc" Date: Fri, 3 Feb 2006 13:36:50 GMT Message-ID: <1138974047_19567@sp6iad.superfeed.net> References: One alternative is to use whatever pulley arrangement you can, and to add a spring between the rope and end of the antenna (insulator would probably be worth having too). How big of a spring? Beats me, how big/heavy is your antenna? - 'Doc Article: 221453 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Verticals versus Horizontal Dipoles Date: Fri, 3 Feb 2006 13:40:40 +0000 (UTC) Message-ID: References: <1138866750.041474.65870@g49g2000cwa.googlegroups.com> <1138961472.184345.67410@g44g2000cwa.googlegroups.com> My geometric argument that beyond distances of several hundred, perhaps 500 miles, the vertical puts down a stronger signal and receives stronger signals than the horizontal dipole cannot be disputed. If you can't be heard at 1000 miles or more using a dipole, you are more likely to be heard using a vertical regardless of what antenna the other fellow is using to receive. At great distances you are much more likely to be heard using a vertical at the same average height above its surroundings. Signal to noise ratio does matter of course. Local noise level is much greater than received from distance sources for obvious reasons. Local noise is vertically polarised. It comes in via groundwave. Noise from a distance is randomly polarised. It comes in via the ionosphere. So in towns and cities, with buildings wiring, overhead power and phone lines, where most of us live, the vertical collects more local noise. In the wide open countryside both types of antenna tend to perform equally well on randomly polarised, distant noise levels. With distant noise and interference and distant signals, both types of antenna result in the same signal to noise ratio in the receiver. But the vertical antenna receives the stronger signal plus noise. If the internal receiver noise is greater than the received signal plus noise then the vertical antenna will win the contest. However, there is another effect which sometimes gives the dipole the advantage. It is multi-hop propagation. The angle of elevation of the radio path increases with the number of hops involved. The number of hops depends on the sun-angle and day or nighttime. Across the States or across the Pacific, for example, the propagation loss can be much less with 2 or 3 hops than it is with one or two hops. Waves sometimes bounce between the F2 and E layers. The increase in elevation angle favours the horizontal dipole. And how many amateurs know the number of hops involved at any point in time? But what eventually favours the vertical over the dipole is their respective service areas. The service area covered by the vertical is many times, far greater than the dipole and so is the world wide distribution of radio amateurs and short-wave listeners. We have now returned to the simplistic but precise Geometry of the ancient Egyptians and Greeks. ;o) ---- Reg, G4FGQ. Article: 221454 of rec.radio.amateur.antenna From: "Richard Fry" References: Subject: Re: Verticals versus Horizontal Dipoles Date: Fri, 3 Feb 2006 08:21:58 -0600 Message-ID: <43e36643_2@newsfeed.slurp.net> "Reg Edwards" wrote: > The low-angle performance of a half-wave dipole, even when > radiating broadside towards the receiver, is very poor in > comparison with a simple vertical. ________________ To the extent that this is true, it is not just a function of the intrinsic radiation patterns of the (horizontally polarised) half-wave dipole and the vertical monopole, but also to the net gain toward the other end of the path including reflections of that intrinsic radiation from the physical environment around the antenna. The performance of an antenna near the earth can depend as much on its installation conditions as its free space pattern. RF Article: 221455 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Verticals versus Horizontal Dipoles Date: Fri, 3 Feb 2006 14:30:12 +0000 (UTC) Message-ID: References: <476-43E3241A-1@storefull-3255.bay.webtv.net> <43e3532e_1@newsfeed.slurp.net> "Richard Fry" wrote in message news:43e3532e_1@newsfeed.slurp.net... > "Richard Harrison" wrote: > > The earth`s attenuation of low-angle radiation from a 1/4-wave vertical > > antenna has a significant effect on the vertical radiation pattern. ee > > Fig. 54-1 on page 465 of B. Whitfield Griffith`s "Radio-Electronic > > Transmission Fundamentals". This figure shows field intensity curves > > versus vertical angle from a 1/4-wave vertical antenna radiating 1 > > kilowatt over earth of average conductivity. Anything below about > > 5-degrees is gone, eaten by the earth`s losses. > ________________ > > This certainly is not true for frequencies below about 2 MHz. If it was > true, MW broadcast stations would have no groundwave coverage -- which of > course is the only useful coverage they _do_ have in the daytime. > > A monopole vertical radiator of any length up to 5/8-wave, when used with a > ground system of ~120 buried radials each ~1/2-wave long, radiates its peak > field very nearly in the horizontal plane regardless of the conductivity of > the ground in which the radials are buried. This gain is within a few > percent of the theoretical peak gain for these radiators when working > against an infinite, perfectly conducting ground plane, as was demonstrated > by the field tests of Brown, Lewis & Epstein in 1937. This principle has > been accepted and used by the FCC and other regulating agencies, and has > been field-proven in thousands of installations going back many decades. > > Once "launched," the groundwave signal is affected by ground conductivity > along the propagation path, earth curvature, obstructions etc. Groundwave > path loss increases with increasing frequency, and above some frequency in > the low HF range, the groundwave is unable to serve a practical purpose. > But that doesn't necessarily mean that the transmit antenna did not generate > the groundwave in the first place, ie, that it radiated zero field in the > horizontal plane and at very low elevation angles. > ========================================== Rich, all what you say is quite true - except that groundwave is radiated at ALL frequencies from a vertical of 5/8-wave or shorter. Useful propagation occurs at 30 MHz and below. But loss in the ground and loss due to obstructions above 1/4-wave in height is high. Solid ragchews across town and small city are quite possible on the 10m band. For predicting groundwave propagation from VLF to HF, download program GRNDWAV3 from website below. ---- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 221456 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Verticals versus Horizontal Dipoles Date: Fri, 3 Feb 2006 14:49:36 +0000 (UTC) Message-ID: References: <476-43E3241A-1@storefull-3255.bay.webtv.net> <43e3532e_1@newsfeed.slurp.net> > For predicting groundwave propagation from VLF to HF, download program > GRNDWAV3 from website below. ====================================== Sorry, I should have said download program GRNDWAV4 from website below. ---- ............................................................ Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 221457 of rec.radio.amateur.antenna From: W8LNA Subject: Re: Pulley Arrangement For Horiz. Antenna ? References: Message-ID: Date: Fri, 03 Feb 2006 16:41:28 GMT Robert11 wrote: > Hi, > > Pretty sure I'll probably be able to come up with something that will more > or less work, but was wondering if any of you folks have a real clever > solution for this: > > Will be stringing a horiz wire listening only antenna between two trees out > back. > Trees have a fair amount of movement, particularly in the winter. > > So, I thought I'd fasten one end securely, and then use the pulley > arrangement, with a hanging weight, like you see in all the pix for this > sort of thing. > > But, we get a lot of ice and freezing rain, and I doubt that the pulley > would really function well, if at all in the winter. > But, perhaps ? > > Think a large metal ring, with a Dacron rope goint thru (one end to the wire > end) would be better ? > Coat Dacron with Silicone Spray ? In Colorado I had a 150' balanced fed dipole hung between a blue spruce and an oak tree, the spruce end fastened and the oak end with a pulley held up with a garage door spring to the oak, a rope through the pulley to the ground and tied off to a screw eye in the trunk of the tree. I used nylon ropes, allowed the dipole to sag a couple feet and never had a problem with it. The garage door spring was about 4 feet long relaxed and I could stretch it a foot or so just pulling on it, it was stretched maybe two feet with the antenna up. The pulley was handy because the feed line broke off and I was able to lower the feed point to the ground and make repairs. The antenna would bounce around on windy days, stayed up with about an inch coating of snow and ice and got me a QSL card from a Clipperton Island expedition. W8LNA Article: 221458 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: Verticals versus Horizontal Dipoles References: Message-ID: Date: Fri, 03 Feb 2006 10:05:30 -0600 Hi Reg Interesting stuff I wonder however if you have any hard data on the merits of using one polarization over another in an electrically noisy environment. For years I have believed (but never seen proof) that on average horizontal is better for this. Any comments? If it is horiz, why? Is it indeed the high radiation angle missing local noise makers or something else..? Cheers Bob VK2YQA Reg Edwards wrote: > There is much discussion about the relative merits of the simple > vertical versus horizontal dipole antennas. Article: 221459 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: 802.11 link References: Message-ID: Date: Fri, 03 Feb 2006 11:11:41 -0600 Hi Bryan Am a little confused. Probably from working nights and not getting enough sleep! From your diagram you are trying to get a signal between the site that has the 24dB gridpack and the "Outside building". You have done some tests from the road and it seems to work. I'd expect you biggest prohblem is the pine forest. They are excellent for attenuating microwave signals! My gut feel is that you'll need a gain antenna at the "outside building" as well as the existing one. This very much depends on the pine tree density that I dont have any actual attenuation figures on. I actually modelled a 2.4GHz link to my mother in laws place about half a mile away through trees and with gridpacks at each end. I had about 50dB of margin but was still worried about 100-200 yards of pine trees. If nothing else you'll get multipath interference and may need to play with polarization. If all else fails try bouncing the signal off the house. You might be surprised! Sorry I cant be more helpful. Pine needles and tree trunks I dont have any figures on! Cheers Bob Bryan Martin wrote: > Well the downside is that I dont think I can pull off the reflector senerio > or complete line of site going over the tree's. At the end of this > powerline is someone else's lot so I can't place anything on or around that. > I only have permission to put the unit in the building located behind > someone's house. Ideally I would rather not have any external antenna's on > the building if at all possible to make the intrusion on property as light > as possible. Thats what brought me to my question. The building is just an > old cheap yard shed more than anything. It has power and 2 windows on the > back side facing the back of the lot. I hope to be able to place the > wireless unit close to the window which should help push the signal. If the > building was another 25-30 foot more to the right I might would have LOS to > it but that is also when you cross over onto someone elses land which is not > an option. As for seeing the signal I am almost completely positive the > grid antenna would be able to intersect the wireless signal at the end of > the powerline but I am unsure if that is enough to get the signal back? Article: 221460 of rec.radio.amateur.antenna From: "Bryan Martin" References: Subject: Re: 802.11 link Message-ID: Date: Fri, 03 Feb 2006 18:12:27 GMT You are right in that I am attempting to pass the signal from the building to the 24db antenna down the powerline NLOS. Distance wise I have passed the signal even further than I need NLOS but it was a strait shot NLOS not off to the right like I am going to attempt. I will be able to actually try this tomorrow and may post my results. "Bob Bob" wrote in message news:effcb3-36o.ln1@p400bob.personal.cox.net... > Hi Bryan > > Am a little confused. Probably from working nights and not getting enough > sleep! > > From your diagram you are trying to get a signal between the site that has > the 24dB gridpack and the "Outside building". You have done some tests > from the road and it seems to work. > > I'd expect you biggest prohblem is the pine forest. They are excellent for > attenuating microwave signals! My gut feel is that you'll need a gain > antenna at the "outside building" as well as the existing one. This very > much depends on the pine tree density that I dont have any actual > attenuation figures on. I actually modelled a 2.4GHz link to my mother in > laws place about half a mile away through trees and with gridpacks at each > end. I had about 50dB of margin but was still worried about 100-200 yards > of pine trees. If nothing else you'll get multipath interference and may > need to play with polarization. > > If all else fails try bouncing the signal off the house. You might be > surprised! > > Sorry I cant be more helpful. Pine needles and tree trunks I dont have any > figures on! > > Cheers Bob > > Bryan Martin wrote: >> Well the downside is that I dont think I can pull off the reflector >> senerio or complete line of site going over the tree's. At the end of >> this powerline is someone else's lot so I can't place anything on or >> around that. I only have permission to put the unit in the building >> located behind someone's house. Ideally I would rather not have any >> external antenna's on the building if at all possible to make the >> intrusion on property as light as possible. Thats what brought me to my >> question. The building is just an old cheap yard shed more than >> anything. It has power and 2 windows on the back side facing the back of >> the lot. I hope to be able to place the wireless unit close to the >> window which should help push the signal. If the building was another >> 25-30 foot more to the right I might would have LOS to it but that is >> also when you cross over onto someone elses land which is not an option. >> As for seeing the signal I am almost completely positive the grid antenna >> would be able to intersect the wireless signal at the end of the >> powerline but I am unsure if that is enough to get the signal back? Article: 221461 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Verticals versus Horizontal Dipoles Date: Fri, 3 Feb 2006 18:41:14 +0000 (UTC) Message-ID: References: > Interesting stuff > > I wonder however if you have any hard data on the merits of using one > polarization over another in an electrically noisy environment. For > years I have believed (but never seen proof) that on average horizontal > is better for this. > > Any comments? If it is horiz, why? Is it indeed the high radiation angle > missing local noise makers or something else..? > > Cheers Bob VK2YQA > > Reg Edwards wrote: > > There is much discussion about the relative merits of the simple > > vertical versus horizontal dipole antennas. ========================================== Local noise is stronger in terms of milli-volts per meter than distant noise for obvious reasons. It is nearer and man-made. Local noise is vertically polarised and comes in via the groundwave and at low elevation angles. Therfore, a vertical antenna which is most sensitive to vertical polarisation and to signals and noise coming from low angles produces greater low-angle signals and low-angle noise in the receiver. Whereas, distant noise comes in from high angles via the ionosphere and is randomly polarised. It is weaker than local noise. It depends on lattitude, the sun, day or night and season of the year. Therefore, a horizontal dipole which is most sensitive to signals and noise coming in from the higher angles produces greater high-angle signals and high-angle noise in the receiver. Now carry on from there. Compare a dipole receiving a low-angle signal with high-angle noise coming in from all directions, with a vertical antenna receiving a high-angle signal with low-angle noise coming in from all directions. ---- Reg. Article: 221462 of rec.radio.amateur.antenna Subject: Re: Verticals versus Horizontal Dipoles From: Dave Oldridge References: Message-ID: Date: Fri, 03 Feb 2006 19:03:22 GMT "Reg Edwards" wrote in news:drqije$rqq$1 @nwrdmz03.dmz.ncs.ea.ibs-infra.bt.com: > Opinions of the many individuals depend on geographic lattitude, World > population densities, what bands happen to be favourites, G5RV's and > how much money there is in the bank. Let's try to remove these > distracting factors. > > I'll put it in somewhat different "simplistic" terms. > > Everything else being equal, the deciding factors are geometry and > trigonometry. The performance of a dipole is better at elevation > angles greater than about 45 degrees and the performance of a vertical > is better at lower angles. That's because the vertical and horizontal > antenna types are oriented at 90 degrees to each other. At elevation > angles around 45 degrees performance is about the same for both types. No, at 45 degrees the PATTERN is about the same (assuming that the horizontal antenna is at least .25 wavelength high). But the actual GAIN over an isotropic source is equivalent down at around 25 degrees. That's because the vertical is normally a monopole, the other half of which is reflected in the ground, whereas the dipole is a dipole and its ground reflection is therefore another dipole stacked with it. Ground losses for the dipole occur at a lower incident angle and further from the antenna and are thus lower. Of course, you can have the best of both worlds by using a vertical dipole, in which case your take-off angle will really be quite low. The main reason why verticals tend to outperform dipoles on low-band DX paths is that the dipoles and other horizontally polarized wires are rarely very high. A lot of them are only about an eighth of a wavelength up or even less. This increases ground losses at all angles and reduces the efficiency of the antenna. And if you can get the current loop to climb up the antenna (by top loading it), a vertical will compete very strongly below about 30 degrees. -- Dave Oldridge+ ICQ 1800667 Article: 221463 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Verticals versus Horizontal Dipoles Date: Fri, 3 Feb 2006 13:17:28 -0600 Message-ID: <11960-43E3AC48-35@storefull-3253.bay.webtv.net> References: Reg wrote: "If you can`t be heard at 1000 miles or more using a dipole, you are more likely to be heard using a vertical regardless of what the other fellow is using to receive." That must not always be the case. Otherwise all the shortwave broadcast stations I`ve worked in, and seen for that matter, would not use horizontal antennas. They have no way of knowing what their audience will use for antennas, and it does not make much difference as following ionospheric reflection, all wave polarizations are available and may be received. At the equator, a time zone is about 1000 miles wide. at the poles (a bad place for shortwave propagation) the width of a time zone is insignificant. All the stations I refer to are in the temperate zone and their targets are likely 1000 miles or so away, though some targets of some stations are only a few hundred miles away. Antennas at these shortwave broadcast stations are a product of studying successful antennas and carefully designing new antennas anf testing their performance in and around their intended targets. They are proved to be effective. Why would a vrtical antenna be better? >From Arnold B. Bailey`s giant antenna catalog in his "TV and Other Receiving Antennas", the free-space gain is the same for a ground plane as it is for a center-fed 1/2-wave dipole. An antenna`s proximity to the earth may change the balance between horizontal and vertical antennas. Terman writes on page 886 of his 1955 edition: "Consider an antenna that is far enough from ground so that the total power radiated by a given set of antenna currents is independent of the presence of the ground. Then a ground reflection that reinforces the main lobe will double the field strength of the main lobe, and so will increase directive gain of the antenna system by a factor of 4. This condition corresponds to an antenna height great enough to make the mutual impedance between the antenna and its image small (see page 894).With horizontally polarized systems this will be the case if the center of the antenna is at least one wavelength above ground; with vertically polarized systems it is true even at lower heights. However. when the antenna is sufficiently close to the ground the effect of the ground reflection is to cause the directive gain to differ from 4. Thus , for a vertical doublet close to the ground, the directive gain is twice the free-space value, since the presence of the ground does not alter the directional pattern and there is no energy radiated in the direction of the hemisphere occupied by the ground. In contrast, the directive gain of a horizontal antenna very close to the ground can be more than 4 as compared with the same antenna in free space, as discussed below in connection with Fig. 23-36." Seems horizontal antenna users are not fools after all. Best wishes, Richard Harrison, KB5WZI Article: 221464 of rec.radio.amateur.antenna From: "void * clvrmnky()" Subject: Re: Another ATAS-120 -- FT-857D question References: Message-ID: Date: Fri, 03 Feb 2006 17:21:34 -0500 On 03/02/2006 4:27 PM, Joe S. wrote: > My FT-857 display is showing the word MTUNE. No mention of this in the > manual. I went through the setup routine for the ATAS-120 and the antenna > seems to be working fine -- it tunes when I change bands and I am making HF > contacts on it. > > Anyone know what this means? "Memory Tune" Google is your friend in this case. Get a searchable copy of the Operating Manual and look for "mtune". Check the "Memory Operation" section of the manual. If you are stuck, I can send you the PDF I have. Article: 221465 of rec.radio.amateur.antenna From: "Richard W. Solomon, W1KSZ" Subject: Thru-Wall Coax Feedthrus Message-ID: Date: Fri, 03 Feb 2006 23:41:51 GMT I know you can get UHF type feedthrus in various lengths, but do they exist in "N" Connector style. What do folks use to run coax thru walls ? Tnx, Dick, W1KSZ Article: 221466 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Verticals versus Horizontal Dipoles Message-ID: <4q58u1pl6ro7oh9f1u9r0l4r0jdmg6nvem@4ax.com> References: <1138866750.041474.65870@g49g2000cwa.googlegroups.com> Date: Sat, 04 Feb 2006 02:57:52 GMT On Thu, 02 Feb 2006 21:57:47 -0500, Mike Coslo wrote: > But here is the interesting thing. On the horizontal antenna, the >listening is a whole heckava lot more pleasant. Another item of interest Mike, you will be aware that a lot of commercial HF amateur transceivers have two HF antenna sockets which can be selected from the front panel. I have always wondered why they do not support a mode of tx on Ant-1, rx on Ant-2 to conveniently support the very configuration you are using. Owen -- Article: 221467 of rec.radio.amateur.antenna From: mcalhoun@ksu.edu Subject: Re: Pulley Arrangement For Horiz. Antenna ? Date: 3 Feb 2006 22:24:36 -0600 Message-ID: References: >... was wondering if any of you folks have a real clever solution for this: >... [snipping pulley and weight vs. spring discussion...] Instead of pulleys, I use a fairly-large (they come in several sizes) screw-in glass insulators like you might use when running a power line; they are easy to install, plenty strong enough, there's no danger of the rope slipping off the pulley wheel, and they are smooth enough that I've never had a rope break because of chafing. And instead of weights, I use one/two/three/... (as many as I think the length and weight of wire needs) screen-door-type springs; they're cheap and seem to last forever. They can be overstretched, but they're cheap.... If you do use a weight, be sure to tie it up (loosely) in such a way that if the antenna breaks, the weight won't clobber someone who just happens to be standing below it! -- --Myron A. Calhoun. Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) Article: 221468 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: Pulley Arrangement For Horiz. Antenna ? Message-ID: References: Date: Sat, 04 Feb 2006 04:59:55 GMT On Fri, 3 Feb 2006 07:46:17 -0500, "Robert11" wrote: >Hi, > >Pretty sure I'll probably be able to come up with something that will more >or less work, but was wondering if any of you folks have a real clever >solution for this: > >Will be stringing a horiz wire listening only antenna between two trees out >back. >Trees have a fair amount of movement, particularly in the winter. > >So, I thought I'd fasten one end securely, and then use the pulley >arrangement, with a hanging weight, like you see in all the pix for this >sort of thing. > >But, we get a lot of ice and freezing rain, and I doubt that the pulley >would really function well, if at all in the winter. >But, perhaps ? > >Think a large metal ring, with a Dacron rope goint thru (one end to the wire >end) would be better ? >Coat Dacron with Silicone Spray ? > >Or,... ? > >Bob > For a 130 foot dipole stretched between 3 trees, I use inexpensive screen door springs from the hardware store at each end. The springs get rusty, but still work and my antenna has yet to break. bob k5qwg Article: 221469 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Verticals versus Horizontal Dipoles Date: Sat, 04 Feb 2006 03:26:46 -0800 Message-ID: <11u93rpp6sqo61e@corp.supernews.com> References: <1138866750.041474.65870@g49g2000cwa.googlegroups.com> <1138961472.184345.67410@g44g2000cwa.googlegroups.com> Mike Coslo wrote: > . . . > I gotta get > these two meters calibrated against each other. > . . . If you don't have a signal generator with variable output, connect the two feedlines through a DPDT switch so it swaps the antenna to each receiver when you switch it back and forth. Write down the meter reading on each receiver for the same signal from the same antenna. It probably won't take long to accumulate a decent cross reference. Of course, you still won't have a clue as to how many dB each meter unit represents. That'll take an investment of a few dollars and an evening to make a step attenuator. Roy Lewallen, W7EL Article: 221470 of rec.radio.amateur.antenna From: "Charlie" Subject: Re: Thru-Wall Coax Feedthrus Date: Sat, 4 Feb 2006 11:05:29 -0600 Message-ID: <11u9no8gjpe5v76@news.supernews.com> References: Amos that is way too simple and effective!! But I can top that..I use a partially opened widow, snipped window screen, piece of wood and lots of adhesive-backed 1" wide weather stripping to seal the whole mess up!! Works FB too!!! -- Charlie-AD5TH www.deepsouthnet.net "Amos Keag" wrote in message news:DqudnefiutHEP3neRVn-iA@comcast.com... > Richard W. Solomon, W1KSZ wrote: > >> I know you can get UHF type feedthrus in various lengths, >> but do they exist in "N" Connector style. >> What do folks use to run coax thru walls ? >> >> Tnx, Dick, W1KSZ > > Dick, I use a drill followed by a length of coax. > > !-) > Article: 221471 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Verticals versus Horizontal Dipoles Message-ID: <176au1dd5a0s6nbri5728ml0ql1j1e1l7j@4ax.com> References: <1138866750.041474.65870@g49g2000cwa.googlegroups.com> <1138961472.184345.67410@g44g2000cwa.googlegroups.com> <11u93rpp6sqo61e@corp.supernews.com> Date: Sat, 04 Feb 2006 21:26:52 GMT On Sat, 04 Feb 2006 03:26:46 -0800, Roy Lewallen wrote: >represents. That'll take an investment of a few dollars and an evening >to make a step attenuator. A greatly overlooked item of test equipment. I recall advising a ham to buy a HP355 step attenuator so that he could quantify the level of interference from nearby power leaks and build a prime facie case for non compliance with emission standards. Although he had just winged at length about his $20,000 plus investment in a tower and VHF/UHF antennas, more on radios, etc... he baulked at spending a $100 on something as unexciting as a step attenuator. This was an opportunity to learn a little more about predicting path loss than a $100 burden. As part of my FSM project for measuring BPL emissions, I went searching the net for kits for RF step attenuators, and all that I found were kits that had gone obsolete, no longer available. Today it should be a piece of cake to do a low cost kit with miniature switches, precision surface mount resistors etc... but we as a community are apparently not sufficiently interested in quantifying things these days. Owen -- Article: 221472 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Verticals versus Horizontal Dipoles Date: Sat, 04 Feb 2006 15:20:39 -0800 Message-ID: <11uadmer968m2a2@corp.supernews.com> References: <1138866750.041474.65870@g49g2000cwa.googlegroups.com> <1138961472.184345.67410@g44g2000cwa.googlegroups.com> <11u93rpp6sqo61e@corp.supernews.com> <176au1dd5a0s6nbri5728ml0ql1j1e1l7j@4ax.com> Owen Duffy wrote: > . . . > As part of my FSM project for measuring BPL emissions, I went > searching the net for kits for RF step attenuators, and all that I > found were kits that had gone obsolete, no longer available. Today it > should be a piece of cake to do a low cost kit with miniature > switches, precision surface mount resistors etc... but we as a > community are apparently not sufficiently interested in quantifying > things these days. A step attenuator which is completely adequate for HF and can easily resolve 1 dB can be made from a few cheap slide switches, some PC board material, and a handful of ordinary 5% quarter watt resistors. Detailed instructions can be found in numerous sources, including the Web -- a Google search brought a large number of hits, the first of which was http://www.arrl.org/tis/info/pdf/9506033.pdf. But I'm afraid that this level of homebrewing is beyond the interest if not the ability of the majority of today's amateurs. Roy Lewallen, W7EL Article: 221473 of rec.radio.amateur.antenna From: "Mr Fed UP" References: <11u9no8gjpe5v76@news.supernews.com> Subject: Re: Thru-Wall Coax Feedthrus Message-ID: Date: Sat, 4 Feb 2006 14:32:02 -0600 What?!!! all these good iders and no one included good ol' duct tape yet. Just restarting a new shack myself... empty room... not much jingle so I'll just stuff mine out the wood slab in the winder too. Good luck Y'all Oh, and don't forget the rubber sillycone sealer. lol 73 K4TWO Gary "Charlie" wrote in message news:11u9no8gjpe5v76@news.supernews.com... > Amos that is way too simple and effective!! But I can top that..I use a > partially opened widow, snipped window screen, piece of wood and lots of > adhesive-backed 1" wide weather stripping to seal the whole mess up!! > Works FB too!!! > > -- > > Charlie-AD5TH > www.deepsouthnet.net > > > "Amos Keag" wrote in message > news:DqudnefiutHEP3neRVn-iA@comcast.com... >> Richard W. Solomon, W1KSZ wrote: >> >>> I know you can get UHF type feedthrus in various lengths, >>> but do they exist in "N" Connector style. >>> What do folks use to run coax thru walls ? >>> >>> Tnx, Dick, W1KSZ >> >> Dick, I use a drill followed by a length of coax. >> >> !-) >> > > Article: 221474 of rec.radio.amateur.antenna From: "Rightrik" Subject: FA: HV ceramic insulators for wire antennas Date: Sun, 5 Feb 2006 01:12:33 +0100 Message-ID: http://cgi.ebay.it/ws/eBayISAPI.dll?ViewItem&item=5862892253&rd=1&sspagename=STRK%3AMESE%3AIT&rd=1 Article: 221475 of rec.radio.amateur.antenna From: "me" Subject: Hi Q TAD Question Date: Sun, 5 Feb 2006 10:37:40 +1000 Message-ID: Hi I need to hear any comments in rgds the performance of the HI Q TAD 4/160 (Tune a dipole ) quality, performance, anything really, ease of tuning, etc etc rgds Article: 221476 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <11u9no8gjpe5v76@news.supernews.com> Subject: Re: Thru-Wall Coax Feedthrus Date: Sat, 4 Feb 2006 19:50:42 -0500 Message-ID: <3b7e$43e54c01$97d56b99$9280@ALLTEL.NET> I kinda wrap it round the stump holdin up the house, and bring er up thru a crack in the floor. lest ways thats how we do it here abouts... "Mr Fed UP" wrote in message news:ZbbFf.19975$eY5.7677@bignews7.bellsouth.net... > What?!!! all these good iders and no one included good ol' duct tape yet. > Just restarting a new shack myself... empty room... not much jingle so > I'll just stuff mine out the wood slab in the winder too. Good luck Y'all > Oh, and don't forget the rubber sillycone sealer. lol > > 73 K4TWO Gary Article: 221477 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Verticals versus Horizontal Dipoles Date: Sun, 5 Feb 2006 03:48:15 +0000 (UTC) Message-ID: References: <1138866750.041474.65870@g49g2000cwa.googlegroups.com> <1138961472.184345.67410@g44g2000cwa.googlegroups.com> <11u93rpp6sqo61e@corp.supernews.com> <176au1dd5a0s6nbri5728ml0ql1j1e1l7j@4ax.com> "Owen Duffy" wrote > but we as a community are apparently not sufficiently interested > in quantifying things these days. ========================================== "When you can measure what you are speaking about and express it in numbers you know something about it. But when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind. It may be the beginning of knowledge but you have scarcely in your thoughts advanced to the state of science." : William Thomson, Lord Kelvin, 1824-1907. ========================================== Arithmetic is not taught in Western schools and universities any more. Even teachers are innumerate! ---- Reg. Article: 221478 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: Verticals versus Horizontal Dipoles References: Message-ID: Date: Sat, 04 Feb 2006 22:09:16 -0600 Tnxs for that Reg What is the generally accepted "number" in either S points or dB of employing horizontal instead of vertical for noise reasons? Obviously it would vary greatly but any idea you have would be helpful. I would also like to get an idea how "critical" it is to make sure ones antenna truly is horizontal (eg not an inverted V or quad loop) if noise is the greatest concern. One would assume you also get a similar affect of "less horizontal noise" from the actual noise source for the same reason. eg power lines radiate well upwards but not so well in groundwave. Cheers Bob W5/VK2YQA Reg Edwards wrote: > > Local noise is stronger in terms of milli-volts per meter than distant > noise for obvious reasons. It is nearer and man-made. Article: 221479 of rec.radio.amateur.antenna From: Butch Magee Subject: YO! Date: Sun, 05 Feb 2006 02:08:49 -0600 Message-ID: <11ubckkq31jh13f@corp.supernews.com> Is that 5 dollars or is it 5 thousand dollars that is the starting bid? KF5DE Article: 221480 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Verticals versus Horizontal Dipoles Date: Sun, 5 Feb 2006 08:15:11 +0000 (UTC) Message-ID: References: "Bob Bob" wrote - > Tnxs for that Reg > > What is the generally accepted "number" in either S points or dB of > employing horizontal instead of vertical for noise reasons? ========================================= Bob, First of all we must entirely disregard the opinions of individuals who may be located in high or low noise districts, areas or regions. I myself live in an industrial, densely populated, area near to a factory with a dozen electrical arc welding machines. Others live out in the wilderness, isolated from modern, electrical noise generating civilisation. There exist statistics of AVERAGE field strength noise levels experienced in cities, small towns and in the open countryside. I have forgotten where to find such statistics but Google may help. The statistics depend very much on frequency. They vary greatly between ELF and HF. Noise levels decrease by crudely 10 dB or 20 dB per octave or decade increase in frequency. Furthermore, at ELF and VLF, noise propagates to far greater distances than at HF. There are always continuous world-wide electrical storms somewhere on the Earth's surface. At 10 KHz noise levels may be several hundred milli-volts per meter. At 7 MHz they may be microvolts per meter. At 30 MHz they are of the order of the internal receiver noise. The noise level indicated by your S-meter is a function of the size of the antenna relative to wavelength and antenna efficiency. It can be crudely calibrated in terms of micro-volts per metre using a little arithmetic. Learn how to estimate. In my own experience (which as I say should be disregarded) the difference in noise level between a horizontal dipole and a vertical is about one or two S-points on the 160 metre band. (Or a difference of 6 or 12 dB.) On the other hand, distant stations come in stronger using a 150-feet, vertical (inverted-L) than they do on a dipole. Not that I have ever used the two types of antenna simultaneously. It's just my opinion. So I prefer the inverted-L. In general, the signal to noise ratio is better and there is less fading. One hop instead of two, via the F2-layer, at night, using a dipole? ---- Reg, G4FGQ Article: 221481 of rec.radio.amateur.antenna From: Scott Subject: Re: Thru-Wall Coax Feedthrus Message-ID: References: Date: Sun, 05 Feb 2006 09:48:14 GMT I drilled the wall and put in a section of PVC. Ran all the coax and then filled the PVC with foam in insulation. Scott N2WMD On Sat, 04 Feb 2006 07:47:23 -0500, Amos Keag wrote: >Richard W. Solomon, W1KSZ wrote: > >> I know you can get UHF type feedthrus in various lengths, >> but do they exist in "N" Connector style. >> What do folks use to run coax thru walls ? >> >> Tnx, Dick, W1KSZ > >Dick, I use a drill followed by a length of coax. > >!-) Article: 221482 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: Thru-Wall Coax Feedthrus Message-ID: References: Date: Sun, 05 Feb 2006 14:38:35 GMT On Fri, 03 Feb 2006 23:41:51 GMT, "Richard W. Solomon, W1KSZ" wrote: >I know you can get UHF type feedthrus in various lengths, >but do they exist in "N" Connector style. >What do folks use to run coax thru walls ? > >Tnx, Dick, W1KSZ www.thewireman.com has bulkhead double-female feedthroughs, some for regular UHF connectors, and, yes, some for N connectors. You could call them to get the various lengths they have in stock. bob k5qwg Article: 221483 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: 4nec2 and linux ?? References: <5JydnZ5Siru-FnjenZ2dnUVZ_sednZ2d@comcast.com> Message-ID: Date: Sun, 05 Feb 2006 10:04:32 -0600 Hi Dan Yes I have tried and failed so far encountering a series of problems centered around the bat file. Its been a while though so pls take the following with memory fade in mind! - The actual necd2.exe file baulks under wine with some kind of malloc problem. I have however succesfully run it under DOSEMU, the DOS emulator. The original problem I had under wine was also wine version specific but I cant remember the details. - The BAT file supplied by Arie has some characters/syntax that are illegal under wine/DOSEMU. From memory these were tabs somewhere. Replacing them with spaces fixed things. I dont know if Arie addressed this in later versions or not. - I had the system running at one stage by using the GUI and getting an error doing the calculation. I then ran it manually under DOSEMU and loaded the output file back into the GUI. Clunky but usable. My next effort was going to be to modify the bat file as supplied with a pause statement (and no calc) that gave me time to launch my own script under DOSEMU. I was also looking into some way to launch a Linux script from a bat file but never delved into that too far. Hope this helps.. If I get excited over fixing this I may do some more experimentation Cheers Bob W5/VK2YQA dansawyeror wrote: > > > All, > > I am trying to run 4nec2 under linux using wine. It loads and runs fine > until a bat file is engaged. The bat files are not supported under > linux. Is there a way to translate bat files to linux? > > Thanks - Dan Article: 221484 of rec.radio.amateur.antenna From: mcalhoun@ksu.edu Subject: Re: Thru-Wall Coax Feedthrus Date: 5 Feb 2006 12:14:07 -0600 Message-ID: References: >>> What do folks use to run coax thru walls ? >I drilled the wall and put in a section of PVC. Ran all the coax and >then filled the PVC with foam in insulation. Obviously one must fill the extra space with something just to keep bugs, snakes, and mice from crawling in, but foaming seems sorta final in that, when one wants to add another coax, the foam will need to be dug out. I've always just stuffed fiberglas insulation around the coax, but here's a QUESTION: Would using steel wool (which mice won't chew) affect currents in and/or on the coax? -- --Myron A. Calhoun. Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) Article: 221485 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: Thru-Wall Coax Feedthrus Date: Sun, 5 Feb 2006 15:30:39 -0500 Message-ID: <11ucnvqhck36j37@corp.supernews.com> References: Foam is not a good idea. It can become very difficult to remove. Best is to use cooper wool. It will not rust nor flake and beasties do not eat it. The stuff has become hard to find, however. 73 Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net wrote in message news:ds5f9f$pa4@unix1.cc.ksu.edu... > >>> What do folks use to run coax thru walls ? > >I drilled the wall and put in a section of PVC. Ran all the coax and > >then filled the PVC with foam in insulation. > > Obviously one must fill the extra space with something just to keep bugs, > snakes, and mice from crawling in, but foaming seems sorta final in that, > when one wants to add another coax, the foam will need to be dug out. > > I've always just stuffed fiberglas insulation around the coax, but here's > a QUESTION: Would using steel wool (which mice won't chew) affect > currents in and/or on the coax? > > -- > --Myron A. Calhoun. Article: 221486 of rec.radio.amateur.antenna From: Jim - NN7K Subject: Re: Thru-Wall Coax Feedthrus References: Message-ID: <4MwFf.1523$rL5.1310@newssvr27.news.prodigy.net> Date: Mon, 06 Feb 2006 00:29:52 GMT Depends--- Choke to R.F.-- NO, Choke to Critters, like mice, rats and other's, YES! and try S.O.S.- they don't like soap in their mouths any more than you did as a kid! Jim NN7K Dan Richardson wrote: > On 5 Feb 2006 12:14:07 -0600, mcalhoun@ksu.edu wrote: > > >>I've always just stuffed fiberglas insulation around the coax, but here's >>a QUESTION: Would using steel wool (which mice won't chew) affect >>currents in and/or on the coax? > > > Naw, it won't have any noticeable effect on the coax. Sometime ago > some proposed packing steel wool around coax as a common mode choke, > however, Walter Maxwell did some measurements and found that was just > about worthless for choking. > > 73, > > Danny > > > > > email: k6mhearrlnet > http://www.k6mhe.com/ Article: 221487 of rec.radio.amateur.antenna From: "me" Subject: Re: Thru-Wall Coax Feedthrus Date: Mon, 6 Feb 2006 11:22:54 +1000 Message-ID: References: well none of the above stops the Lightning getting into shack and racing around zapping all and sundry ? i got a Border Collie here that could get coax into a shack, stop getting gear zapped , well thats different heres what I did, get ur coax from INSIDE TO OUTER WALL, Terminate it pl259's or whatever, make 2 pieces of ally box section that will fit together, on the outer side, alighn SO-239's on both ally pieces, one to collect the coax from INSIDE the shack, and another row to collect the terminated coax from the antennas,, slide the ally box section together, and connect centre of SO-239's to SO -239's with BANANA PLUG centres to ensure a RF connection, position a Bolt on one side of one ally section, and form a S shaped piece of ally flat with a hole drilled into it, to take a thin piece of rope, terminate all so-239s with appropiate coax's ?/ all done, STORM comes, pull rope, S shape pivots against the bolt in the ally section and UNPLUGS all antennas together, KEEPING all the nasties OUTSIDE, when storm has gone plug it back in, been using one for 15 yrs, 73 will gladly take some pics if anyone wants "David Shrader" wrote in message news:FMedndDAK4Vj-nvenZ2dnUVZ_tCdnZ2d@comcast.com... > Scott wrote: >> I drilled the wall and put in a section of PVC. Ran all the coax and >> then filled the PVC with foam in insulation. Scott >> N2WMD >> >> On Sat, 04 Feb 2006 07:47:23 -0500, Amos Keag >> wrote: >> >> >>>Richard W. Solomon, W1KSZ wrote: >>> >>> >>>>I know you can get UHF type feedthrus in various lengths, >>>>but do they exist in "N" Connector style. >>>>What do folks use to run coax thru walls ? >>>> >>>>Tnx, Dick, W1KSZ >>> >>>Dick, I use a drill followed by a length of coax. >>> >>>!-) > > FOAM?? No! > > Dick, get a tube of colored caulking compound. I use BROWN for a brown > house [of course]. It makes a weather and insect proof seal and is easily > removed if needed [simply pull the coax and both the coax and caulking > come right out]. > > Dave > Article: 221488 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: Verticals versus Horizontal Dipoles Date: Sun, 5 Feb 2006 22:50:55 -0500 Message-ID: <11udhp9n9si5kee@corp.supernews.com> References: <1138866750.041474.65870@g49g2000cwa.googlegroups.com> <1138961472.184345.67410@g44g2000cwa.googlegroups.com> <11u93rpp6sqo61e@corp.supernews.com> <176au1dd5a0s6nbri5728ml0ql1j1e1l7j@4ax.com> Reg: Your making such an obviously false statement calls into question all of your pronouncements. There is not a single student in my University (or any other similar institution that I know of) who will graduate without providing many demonstrations of their significant arithmetic and mathematical ability. Your veracity is gone. Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Reg Edwards" wrote in message news:ds3shv$295$1@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com... > ========================================== > > Arithmetic is not taught in Western schools and universities any more. > Even teachers are innumerate! > ---- > Reg. > > Article: 221489 of rec.radio.amateur.antenna From: "Old Ed" References: <4MwFf.1523$rL5.1310@newssvr27.news.prodigy.net> Subject: Re: Thru-Wall Coax Feedthrus Message-ID: Date: Mon, 06 Feb 2006 04:47:12 GMT Well, maybe... One of our Dobermans ate a whole box of SOS, apparently because he LIKED the flavor of the soap! 73, Ed, W6LOL "Jim - NN7K" wrote in message news:4MwFf.1523$rL5.1310@newssvr27.news.prodigy.net... > Depends--- Choke to R.F.-- NO, Choke to Critters, like > mice, rats and other's, YES! and try S.O.S.- they don't > like soap in their mouths any more than you did as a kid! > Jim NN7K > > > Dan Richardson wrote: > > On 5 Feb 2006 12:14:07 -0600, mcalhoun@ksu.edu wrote: > > > > > >>I've always just stuffed fiberglas insulation around the coax, but here's > >>a QUESTION: Would using steel wool (which mice won't chew) affect > >>currents in and/or on the coax? > > > > > > Naw, it won't have any noticeable effect on the coax. Sometime ago > > some proposed packing steel wool around coax as a common mode choke, > > however, Walter Maxwell did some measurements and found that was just > > about worthless for choking. > > > > 73, > > > > Danny > > > > > > > > > > email: k6mhearrlnet > > http://www.k6mhe.com/ Article: 221490 of rec.radio.amateur.antenna From: "GS" References: <1139180401.897959.93150@g44g2000cwa.googlegroups.com> Subject: Re: Beldon 8214 Message-ID: <8%KFf.1435$J%6.86558@news20.bellglobal.com> Date: Mon, 6 Feb 2006 11:41:47 -0500 See www.k1cra.com This product is very similar to RG8/U I would look at the CQ "Super-8" which is an even better product in terms of lower loss. 73's Guenther VE3CVS wrote in message news:1139180401.897959.93150@g44g2000cwa.googlegroups.com... > Wanted 50-60' of belden 8214 please assist, will pay pal! > > Max > Article: 221491 of rec.radio.amateur.antenna From: "R. Scott" Subject: Re: Beldon 8214 Message-ID: References: <1139180401.897959.93150@g44g2000cwa.googlegroups.com> <8%KFf.1435$J%6.86558@news20.bellglobal.com> Date: Mon, 6 Feb 2006 18:17:00 GMT GS" wrote in message news:8%KFf.1435$J%6.86558@news20.bellglobal.com... > See www.k1cra.com > > This product is very similar to RG8/U I would look at the CQ "Super-8" > which is an even better product in terms of lower loss. > > 73's > Guenther VE3CVS I use this by DavisRF products. Very Reasonable and great shipping . 9913, double shield (100%), 50 ohm, solid 9.5 AWG copper center cond, 84% VP, PVC jacket. http://www.davisrf.com/ham1/coax.htm Article: 221492 of rec.radio.amateur.antenna From: "Bryan Martin" Subject: Passive Repeater Message-ID: <7_MFf.10650$915.3051@southeast.rr.com> Date: Mon, 06 Feb 2006 18:57:07 GMT Ok, my first test failed so far. Example of what I am doing is here http://home.triad.rr.com/tempdir/images/layout.jpg. My next thing I am thinking about trying is to place some kind of somewhat small (no billboard) passive repeater at the end of the powerline attached to a utility pole where it meets the field. No power this far out and trenching is not an option. I can google and find hords of info about people using passive repeaters to bend the signal but I cannot find an actual passive repeater or how to build one. Also when dealing with this type of repeater would it force me to have directional antenna's at both ends where currently I have only the one directional parabolic grid at the top of the powerline and just a standard AP inside the building. Anyone think of anything else that may work. going over the forest is also not an option. I own the land where the grid antenna is located but I dont own the land where the building is located as I just have permission to place a AP at that site. I am trying to make the impact as minimal as possible at that site. Bryan -- Poor planning on your part does not constitute an emergency on my part. Article: 221493 of rec.radio.amateur.antenna From: "AAA RF Products" Subject: Coax Cable & Connector Catalog Message-ID: Date: Mon, 6 Feb 2006 11:56:58 -0800 For your free copy of our new catalog, Please email sales@AAARFProducts.com or see www.aaarfproducts.com or call 949 481 3154 (San Clemente, CA, USA) No minimum order. No handling charges. Article: 221494 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: Passive Repeater References: <7_MFf.10650$915.3051@southeast.rr.com> Message-ID: <96okb3-td.ln1@p400bob.personal.cox.net> Date: Mon, 06 Feb 2006 14:29:29 -0600 Hi again Bryan A passive repeater is very simple. You simply take two antennas and join them with feeder, then point one antenna at one end of the link and the other at the other end of the link. You may need to separate them some so they dont interfere with each others capture pattern. There will be a link budget that defines how much system gain (and thus antenna gain) you need. You could conceivably get away with using the standard AP antenna at that one end. As I said previously the software I use for this is broken and I am not in a position to redo it by hand just at the moment. There is a simple formula for determining path loss over a line of sight path. You just do that twice with the received strength at the repeater being the source power for the next link (minus about 3dB) What are the distances from each site to the passive rptr location? If one does the calclulation then outoput power and receiver sensitivity is also needed. Cheers Bob Bryan Martin wrote: > Ok, my first test failed so far. Example of what I am doing is here > http://home.triad.rr.com/tempdir/images/layout.jpg. My next thing I am > thinking about trying is to place some kind of somewhat small (no billboard) > passive repeater at the end of the powerline attached to a utility pole > where it meets the field. No power this far out and trenching is not an > option. I can google and find hords of info about people using passive > repeaters to bend the signal but I cannot find an actual passive repeater or > how to build one. Also when dealing with this type of repeater would it > force me to have directional antenna's at both ends where currently I have > only the one directional parabolic grid at the top of the powerline and just > a standard AP inside the building. Anyone think of anything else that may > work. going over the forest is also not an option. I own the land where > the grid antenna is located but I dont own the land where the building is > located as I just have permission to place a AP at that site. I am trying > to make the impact as minimal as possible at that site. > > Bryan > Article: 221495 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Verticals versus Horizontal Dipoles Date: Mon, 6 Feb 2006 21:47:07 +0000 (UTC) Message-ID: References: "Bob Bob" wrote > I would also > like to get an idea how "critical" it is to make sure ones antenna truly > is horizontal (eg not an inverted V or quad loop) if noise is the > greatest concern. > > One would assume you also get a similar affect of "less horizontal > noise" from the actual noise source for the same reason. eg power lines > radiate well upwards but not so well in groundwave. ======================================== Bob, The angle of the 'horizontal' dipole relative to the horizontal, whether it is an inverted-V or not, makes negligible difference to the amount of noise it collects. It is non-critical in this respect. The incoming, mainly distant noise comes in from all directions and angles and is randomly polarised. Except, that is, for locally generated noise, which is mainly a vertically polarised ground-wave and from low angles to which the horizontal dipole is quite insensitive. Noise radiated from nearby elevated power lines is probably randomly polarised and is collected in similar proportions by both horizontal and vertical antennas. When a power line is half-mile or more away I would guess that the received noise reverts to vertically polarised groundwaves which at HF are rapidly attenuated. The horizontal waves are even more rapidly attenuated. Noise can be studied only from its statistical probability distributions versus direction, angle, frequency, receiver bandwidth and time. The opinions and anecdotes of individuals matter only to the inviduals concerned and their locations on the Earth's surface. ---- Reg. Article: 221496 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Passive Repeater Date: Mon, 6 Feb 2006 17:24:05 -0600 Message-ID: <22148-43E7DA95-635@storefull-3258.bay.webtv.net> References: <7_MFf.10650$915.3051@southeast.rr.com> Bryan Martin wrote: "I can google and find hordes of info about people using passive repeaters to bend the signal but I cannot find an actual passive pepeater or how to build one." Maybe that is because the billboard reflector is close to 98% efficient, while back-to-back antennas are only about 30% efficient. Best regards, Richard Harrison, KB5WZI Article: 221497 of rec.radio.amateur.antenna From: Russ Subject: Re: 4nec2 and linux ?? Message-ID: References: <5JydnZ5Siru-FnjenZ2dnUVZ_sednZ2d@comcast.com> <4AydnZv0TsUhJnreSa8jmw@karoo.co.uk> Date: Mon, 06 Feb 2006 23:58:51 GMT On Mon, 06 Feb 2006 21:12:34 +0000, Dan Andersson wrote: >dansawyeror wrote: > >> All, >> >> I am trying to run 4nec2 under linux using wine. It loads and runs fine >> until a bat file is engaged. The bat files are not supported under linux. >> Is there a way to translate bat files to linux? >> >> Thanks - Dan > > >Emulating a NEC for Windooze in Linux?! > >Why are you not running a native NEC - compiled for Linux? > >Try > >http://radio.linux.org.au/?sectpat=antenna&ordpat=title > > >Cheers > > >Dan / M0DFI Nice concept. Too bad that www.qsl.net is offline or otherwise inreachable (at least right now). R Article: 221498 of rec.radio.amateur.antenna From: Russ Subject: Re: 4nec2 and linux ?? Message-ID: References: <5JydnZ5Siru-FnjenZ2dnUVZ_sednZ2d@comcast.com> <4AydnZv0TsUhJnreSa8jmw@karoo.co.uk> Date: Tue, 07 Feb 2006 00:04:44 GMT On Mon, 06 Feb 2006 21:12:34 +0000, Dan Andersson wrote: >dansawyeror wrote: > >> All, >> >> I am trying to run 4nec2 under linux using wine. It loads and runs fine >> until a bat file is engaged. The bat files are not supported under linux. >> Is there a way to translate bat files to linux? >> >> Thanks - Dan > > >Emulating a NEC for Windooze in Linux?! > >Why are you not running a native NEC - compiled for Linux? > >Try > >http://radio.linux.org.au/?sectpat=antenna&ordpat=title > > >Cheers > > >Dan / M0DFI Follow-up to my follow-up...all of the servers listed in "whois" are not reachable, the pings time out. I hope there are mirrors available and someone can change the pages listed above. R Article: 221499 of rec.radio.amateur.antenna From: "Bryan Martin" References: <7_MFf.10650$915.3051@southeast.rr.com> <22148-43E7DA95-635@storefull-3258.bay.webtv.net> Subject: Re: Passive Repeater Message-ID: <9fSFf.10664$915.8953@southeast.rr.com> Date: Tue, 07 Feb 2006 00:56:37 GMT You lost me somewhere. Was this supposed to help or was it just a slam? "Richard Harrison" wrote in message news:22148-43E7DA95-635@storefull-3258.bay.webtv.net... > Bryan Martin wrote: > "I can google and find hordes of info about people using passive > repeaters to bend the signal but I cannot find an actual passive > pepeater or how to build one." > > Maybe that is because the billboard reflector is close to 98% efficient, > while back-to-back antennas are only about 30% efficient. > > Best regards, Richard Harrison, KB5WZI > Article: 221500 of rec.radio.amateur.antenna From: "Bryan Martin" References: <7_MFf.10650$915.3051@southeast.rr.com> <96okb3-td.ln1@p400bob.personal.cox.net> Subject: Re: Passive Repeater Message-ID: Date: Tue, 07 Feb 2006 00:55:38 GMT The building location is maybe 500 feet away from where the repeater would be. The parabolic grid is maybe 3000-3500 feet away from the repeater location. As for the output we will talk about the grid antenna first. It is currently at 28mw which is adjustable up to 250mw but I would be way over the limit with the 24db gain antenna (also the way I understand it which is a learning in process I should not need to increase the xmit power due to the focus of the directional type antenna). Plus since this will be out in the open in a sealed weather proof box I don't want heating problems or bird nuking etc.... Sadly I am unable to find out what the current MN-700 AP which is located in the building transmits at or what the gain of the stock antenna's is. I have purchased another AP similar to the one hooked to the grid antenna which by default would be transmitting at 28mw with 7db gain rubber duck antenna. Passive antenna "You simply take two antennas and join them with feeder". Help me out a bit here if possible. So I take two antenna's such as (http://sharperconcepts.zoovy.com/c=6buOjuTwyhk8OnXuIOz6ZqKK6/product/YSC-HG2409Y) and hook the pig tails together? Point one at the grid and one at the building right? Does the gain really matter? Do they need to both be directional? "You may need to separate them some so they dont interfere with each others capture pattern." I dont think this would be an issue as one would have to be on 1 side of the utility pole and one on the other. Do you think this would cause problems? "Bob Bob" wrote in message news:96okb3-td.ln1@p400bob.personal.cox.net... > Hi again Bryan > > A passive repeater is very simple. > > You simply take two antennas and join them with feeder, then point one > antenna at one end of the link and the other at the other end of the link. > You may need to separate them some so they dont interfere with each others > capture pattern. > > There will be a link budget that defines how much system gain (and thus > antenna gain) you need. You could conceivably get away with using the > standard AP antenna at that one end. As I said previously the software I > use for this is broken and I am not in a position to redo it by hand just > at the moment. There is a simple formula for determining path loss over a > line of sight path. You just do that twice with the received strength at > the repeater being the source power for the next link (minus about 3dB) > > What are the distances from each site to the passive rptr location? If one > does the calclulation then outoput power and receiver sensitivity is also > needed. > > Cheers Bob > > Bryan Martin wrote: >> Ok, my first test failed so far. Example of what I am doing is here >> http://home.triad.rr.com/tempdir/images/layout.jpg. My next thing I am >> thinking about trying is to place some kind of somewhat small (no >> billboard) passive repeater at the end of the powerline attached to a >> utility pole where it meets the field. No power this far out and >> trenching is not an option. I can google and find hords of info about >> people using passive repeaters to bend the signal but I cannot find an >> actual passive repeater or how to build one. Also when dealing with this >> type of repeater would it force me to have directional antenna's at both >> ends where currently I have only the one directional parabolic grid at >> the top of the powerline and just a standard AP inside the building. >> Anyone think of anything else that may work. going over the forest is >> also not an option. I own the land where the grid antenna is located but >> I dont own the land where the building is located as I just have >> permission to place a AP at that site. I am trying to make the impact as >> minimal as possible at that site. >> >> Bryan >> Article: 221501 of rec.radio.amateur.antenna From: pbreed@netburner.com Subject: Rocket Antennas... Date: Mon, 06 Feb 2006 17:11:44 -0800 Message-ID: <9asfu1lrtksihlbhvl2ns6kk948apfg02l@4ax.com> I'm helping the SDSU mechanical engineering students with their Rocket. See: http://www-rohan.sdsu.edu/%7esharring/sdsurocket.html I've asked for help on this group before, but the response went over my head. I a reasonably skilled EE, with ZERO antenna design experience. I would like to design an antenna that was conformal with the rocket main tube. The rocket is about 8" in diameter and all metal. I need two antennas.... I have two channels a 70cm ATV transmitter and a 900Mhz non-ham telemetry radio. For the last attempt: Telemetry: I put two 1/4 wave verticals on opposite sides of the rocket fed them with a minicircuits splitter. This worked well as I got data from lift off to impact. ATV Last attempt I just had a single 1/4 wave dipole sticking out one side of the rocket. As the rocket rolled the signal faded in and out. The last time I asked this question I got a response that I could not use because I did not understand it. So I'm looking for someone to help that can do the detail design. IE provide instructions build a tobe with this pattern on it, hook up coax here and trim this spot to adjust SWR. I'm perfectly willing to get the fabrication done, but the design is beyond me. I realize that I'm asking a lot, but any one that wants to help with the antenna can have a front row seat in the block house to watch it launch, and some cool video tape ;-) (The launch will be at the MTA near Mojave, CA) Paul (Kl7JG)