Subject: glowbugs V1 #200
glowbugs Monday, December 1 1997 Volume 01 : Number 200
Date: Sun, 30 Nov 1997 14:43:22 -0600
From: w5hvv@aeneas.net (Roderick M. Fitz-Randolph)
Subject: Hartley Oscillator from 6BL7-GTA??????
I've run across two tubes in my trunk-of-tubes that have the
designation 6BL7-GTA. I looked up the characteristics to
see the differences between this and the much-favored 6SN7.
Following are the characteristics for both from the RCA
Receiving Tube Manual, Technical Series RC-19.
VERTICAL DEFLECTION OSCILLATOR OR AMPLIFIER:
MAXIMUM RATINGS AS OSCILLATOR (each unit)
Maximum Ratings 6SN7-GT 6BL7-GTA
DC Plate Voltage:.................... 450 Max...500 Max volts
Peak Cathode Current:................ 70 Max...210 Max ma
Plate Dissipation for either plate:.. 5 Max... 10 Max watts
For both Plates with
both units operating:............. 7.5 Max... 12 Max watts
Peak Heater Cathode Voltage:......... 200 Max...200 Max volts
I am a newcomer to the Glowbugs Reflector but it seems to me
that a 6BL7-GTA would make an even better choice for a Hartley
Oscillator than the tried and true 6SN7.... or am I missing
something here? I've read recently where the 6SN7, with plates
tied together, makes a very good Hartley or am I confusing it
with a regen? I would really like to hear from anyone that has
prior experience with the 6BL7 as to its suitability for the
famous Hartley and whether my layman's analysis of it bears any
credibility or not.
Thank you.
Rod, N5HV
w5hvv@aeneas.net
Date: Sun, 30 Nov 1997 21:03:02 +0000
From: Sandy W5TVW <ebjr@worldnet.att.net>
Subject: FS/FT: Bendix NOS "MIL" connectors
I have a quantity of Bendix 19 pin and 32 pin MIL
type connectors.
Type numbers are:
PT01CE 14-19R (SP)
" 14-19S (SP)
" 18-32P (SR)
" 18-32S (SP)
Most are NOS still in the vaporproof poly bags.
Would like to trade this lot and the installation tools
Probably have about 100 or more. These cost around $10-$15
each at the time and the tooling is also expensive. Will be
willing to let the whole lot go for $100 plus shipping/packing.
If you are interested, let me know and I'll supply more details.
73,
E. V. Sandy Blaize, W5TVW
"Boat Anchors collected, restored, repaired, traded and used!"
417 Ridgewood Drive
Metairie, LA., 70001
**860 Hartley 'ECO' under construction****
*** Looking for a TRC-10 transceiver ******
*** Looking for an RAL receiver ***********
Date: Sun, 30 Nov 1997 14:57:38 -0800 (PST)
From: Ken Gordon <keng@uidaho.edu>
Subject: Re: Hartley Oscillator from 6BL7-GTA??????
Do it!!! It will work just fine.
Ken W7EKB
Date: Sun, 30 Nov 1997 19:50:35 -1000
From: Jeffrey Herman <jeffreyh@hawaii.edu>
Subject: RE: ARRL cracks xtals with Tri-Tet? (fwd)
- ---------- Forwarded message ----------
Date: Sun, 30 Nov 1997 15:01:00 -1000
From: "Parker, Al" <al_parker@research.kaiseral.com>
To: Old Tube Radios <boatanchors@theporch.com>
Subject: RE: ARRL cracks xtals with Tri-Tet?
Hi folks,
I've been waiting for a reference to this "wooden" xmtr for some
time. I would have mentioned it if I had written my "bio" a while
back. I built one of them, from an early ARRL book, in 1956, in
preparation for receiving my novice license. (In West Hartford, CT,
home of the League at that time) I had 2 xtals (for a short time)
The novice band one fractured immediately (on a "dummy load" light
bulb). A replacement of course did the same. Had a surplus, out of
band xtal, that was the only one that would hold up. At $5 ea., I
didn't buy many Peterson xtals. I didn't have the knowledge, nor did
my buddies (at 14 yrs old) to figure it out. Think we did try a dial
bulb in series. Never did get the thing to work, guess I got sympathy
from my folks, to help finance a DX-35 kit, just introduced.
Thanks for the memories.
73, Al, W8UT al_parker@kacc.com
Dublin, CA
================================
From: MNHopkins@aol.com
Men, say it ain't so!
Tell me the Tri-Tet isn't the "crystal cracker" of old!
What about the little ones? On page 34 of the December, 1946 QST, in
describing the famous wooden rail "Most Inexpensive Transmitter" using
a 6F6
that would make a modern products liability lawyer faint, we read:
"The oriinal version of W9JVI used the grid-plate circuit; but the QST
version uses the Tri-tet circuit because it gives a little better
operation on the second harmonic."
Did Byron Goodman, W1DX, lead a generation astray?
Date: Sun, 30 Nov 1997 19:52:05 -1000
From: Jeffrey Herman <jeffreyh@hawaii.edu>
Subject: Schematics... (fwd)
- ---------- Forwarded message ----------
Date: Sun, 30 Nov 1997 09:34:25 -1000
From: Ken Gordon <keng@UIDAHO.EDU>
To: Old Tube Radios <boatanchors@theporch.com>
Subject: Schematics...
I have just scanned the schematic diagrams and parts lists for 4
transmitters which have been the subject of discussion on this list
lately.
Although I have NOT yet made them available on my web page, I thought I
should at least provide the URL for it now:
http://www.mines.uidaho.edu/~keng/
These will be:
1) The 813 Xtal oscillator from the back of QST for 1938.
2) A push-pull xtal oscillator transmitter using 2 ea 807s from my 3rd
edition of "Practical Radio Communications". This was originally from RCA
Tech Tips # TT-3 and was originally configured for 5 meters.
3) A push-pull dual triode transmitter, circa 1932. Most of the circuit is
from the above mentioned handbook (Nilson and Hornung), slightly modified
by myself from information taken from the following circuit.
4) 1932 Hartley taken from an article by George Grammer originally
published in QST and subsequently modified slightly by NA4G Bob Keyes for
use with more a more modern tube.
I intend to also re-draw, scan, and post a copy of the Frank Jones
push-pull xtal controlled 10 watter which was recently mentioned. This
transmitter is extremely simple and looks like a lot of fun to build and
operate. It was originally published for use with either a 53 or a 6A6,
both of which are functionally equivalent to the 6N7, although I think any
small dual triode would work in this rig.
In case you don't think these qualify as BA, think of the power-supplies
which would be needed to drive these, especially if you were to use a pair
of 304TLs in the PP oscillator transmitter.
Ken W7EKB
Date: Mon, 1 Dec 1997 09:34:30 -0800 (PST)
From: Ken Gordon <keng@uidaho.edu>
Subject: Schematics...
OK. I have TWO out of the 5 I wanted to put up now in operation.
The URL is:
http://www.mines.uidaho.edu/~keng/schematics/
There are short descriptions of each circuit, and places to click to view
the schematics.
The Jones rig, and the Hartley are available immediately and can be
printed from the screen.
The other three will be available as soon as I can RE-draw them in REALLY
dark ink, re-scan, and reduce to proper size for printing.
Enjoy.
Ken W7EKB
Date: Mon, 1 Dec 1997 13:33:47 -0400
From: "Brian Carling" <bry@mnsinc.com>
Subject: Re: CCF days - again
We've added some new things to the CCF RADIO WebPages!
Please have a look when you get a chance.
http://www.mnsinc.com/bry/ham/ccfradio.htm
There are pictures of some fine British WW2-era radios along with
the memoirs of some of the CADETS who operated them from various
schools around the UK in the 1960s etc.
You will thoroughly enjoy their recollections of the good old days of
Daytime AM operations that thrilled many a young schoolboy!
Cheers - Bry, G3XLQ / AF4K
Date: Mon, 1 Dec 1997 21:55:55 +0000
From: Sandy W5TVW <ebjr@worldnet.att.net>
Subject: RE: Modifications
Gee, I guess I coulda been crowned "Command Set/ARC-5 Changer"
back during my grammer school/high school days! Converted more
receivers to "AC-DC" than I want to count!
On changing currently available and unavailable "old gear" I have
a strong tendency to dislike "added" holes, especially on front panels
of gear! There are changes that are very useful like product detectors,
mechanical filter adapters, etc. that can be added without butchering up
a piece of gear. I have a National NC-183D with an added product detector
module built up and plugged in to the NBFM adapter socket. The RADIO-PHONO
switch doing the audio switching. All the changes can be removed VERY
easily and the set returned to its original condition.
I have a Heath HR-10B, the 6X4 rectifier socket is now occupied by
an 0B2 regulator tube and the supply rectifiers are now silicon diodes.
Everything mounted on a new terminal strip soldered to the chassis rear
apron inside. No new holes! It too can be changed back to "stock" if
someone desires.
I have seen receivers with added "S" meters in a hole that looks like
it was gouged by a cold chisel! I remember seeing a beautiful Hallicrafters
S-40 (original one) with a Calrad Jap "S" meter added to it's panel!
Jeese, what's wrong with a seperate little box sitting atop the set? "Velcro"
will hold it there without holes!
One of the attractive things about this older tube gear is, one can
tinker with the insides, sometimes improve things, and learn what
should and should not be tried. Most of the Rice-box gear is almost
impossible to experiment with, and very unforgiving of any brash
mistakes by the "tinkerer"!
Some "dogs" are not REALLY worth the effort it would take to
re-manufacture them to quasi-original spendor, so they are "parted
out", thereby supplying those who have restorable gear, a parts source
long since gone! I do agree with Dave Stinson when I see an
untouched ARC-5 receiver. I'd rather trade it off to someone looking
for a pristine one for a couple of "changed" ones if I wanted to
"tinker" with them or use them for something other than receivers.
It's ashamed to break up one of these nowadays, as they ain't making
any more of 'em!
Just my 2 pennie's worth.
73,
E. V. Sandy Blaize, W5TVW
"Boat Anchors collected, restored, repaired, traded and used!"
417 Ridgewood Drive
Metairie, LA., 70001
**860 Hartley 'ECO' under construction****
*** Looking for a TRC-10 transceiver ******
*** Looking for an RAL receiver ***********
End of glowbugs V1 #200
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