Subject: GLOWBUGS digest 134

From: [email-masked]
Date: Mon, 18 Mar 1996 19:40:44 -0600 (CST)

GLOWBUGS Digest 134

Topics covered in this issue include:

  1) 1937 edt. of amateur radiotelephony
	by robert fowle <[email-masked]>
  2) 3579.545 tonight anyone?
	by [email-masked]
  3) What kind of buffer amp for freqmeter vfo?
	by [email-masked]
  4) Driver for xtal socket
	by Conard Murray <[email-masked]>
  5) Re: What kind of buffer amp for freqmeter vfo?
	by [email-masked]

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Date: Sun, 17 Mar 1996 21:11:08 -0500 (EST)
From: robert fowle <[email-masked]>
To: [email-masked]
Cc: [email-masked], [email-masked]
Subject: 1937 edt. of amateur radiotelephony
Message-ID: <[email-masked]>

greetings;
        as the subject says, i have the 1937 edtion of amateur radiotelephony.
would like to trade this for manuals i don't have.
if interested, please e-mail list of what ya have availible to trade.
thanks

===========================================================]-[->
Robert Fowle
The HAMMARLUND Historian
Ph. voice or fax  517-789-6721
1215 Winifred
Jackson, Mich. 49202-1946
E-mail at: [email-masked]
                              HAMMARLUND LITERETURE WANTED
===========================================================]-[->

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Date: Mon, 18 Mar 1996 13:44:20 -0500 (EST)
From: [email-masked]
To: [email-masked], [email-masked]
Cc: [email-masked] ()
Subject: 3579.545 tonight anyone?
Message-ID: <[email-masked]>

Reminder..... QRG 3579.545 QTR 0300/0400/0500/0600UTC

Fires ye up yer bottleburners an' plys the ether.....(:+}}.....

73/ZUT DE NA4G/Bob

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Date: Mon, 18 Mar 1996 13:50:15 -0500 (EST)
From: [email-masked]
To: [email-masked]
Cc: [email-masked] ()
Subject: What kind of buffer amp for freqmeter vfo?
Message-ID: <[email-masked]>

I was playing around with a dead, cut up AN/URM-32 freq meter (last gasp
of the BC-221).  It sports a 5814A osc/cathode follower buffer, but
does not quite have the poop to run Big Bertha Radiomarine in the xtal
holder position.  My suspicion is that an untuned 6AG7 or 6BH7 or some
sort of pentode that might fit in a large 9 pin mini socket would work.
That would make a mean vfo driver for almost any sort of breadboard
project.....(:+}}.....  

How would other Globuggites do it?  Just for discussion's sake?

73/ZUT DE NA4G/Bob

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Date: Mon, 18 Mar 1996 13:28:41 +0800
From: Conard Murray <[email-masked]>
To: Multiple recipients of list <[email-masked]>
Subject: Driver for xtal socket
Message-ID: <[email-masked]>

-- [ From: Conard Murray * EMC.Ver #2.5.02 ] --

I imagine what 'ol Bob needs is some sort of untuned voltage amplifier but
that depends entirely on the circuit in Bertha. If voltage gain is all that
is necessary, then a small triode would work ok. If power is needed, then
something along the 6AG7 would be a good choice. 
One of the resistance-coupled amplifier designs from a mid-50's Handbook
comes to mind if  proper selection of bypass elements were chosen. 

Everyone remember to join in the party on 3.579 on the hour...

ZUT! 
de Conard ws4s

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Date: Mon, 18 Mar 1996 15:39:42 -0500 (EST)
From: [email-masked]
To: [email-masked] (Rhett T. George)
Cc: [email-masked] (), [email-masked]
Subject: Re: What kind of buffer amp for freqmeter vfo?
Message-ID: <[email-masked]>

> 
>  - Bob -
> 
> Hi, there.  I think you are going after the right stuff in using a pentode
> buffer amp.  The 6CL6 is a 9-pin with 7.5 W plate dissipation, the 6CM6
> has a max of 12 W.  Either should do the job for Big Bertha.  My guess is
> that you are running the osc at 1.8 MHz (whoops, 1.8mc/s) or 3.6.  A
> pentode plate load of inductor paralleled with a resistor small enough
> to quench any tendency to oscillate at this stage gets my vote.
> 
> Let us know what happens and how it works, please.
> 
> 73					Rhett - KE4HIH
> 

Good, some discussion.....

The Freqmeter oscillates at 160 meters, after downward padding, and the
buffer is an untuned cathode follower.  As-is, it will drive Big Bertha's
xtal oscillator stage (an 807) with just sufficient drive to work straight
through on 160 and get the full 200 watts out of the final.  On doubling,
it is way insufficient to drive at all, even if the xtal oscillator is still
on 160 and I am using Bertha to double up from there.  Thus, I need to
up the drive by a factor of 3-10x to get sufficient voltage to drive
Big Bertha's 807 xtal oscillator.  So, some sort of standard small driver
tube would be appropriate.  For Globugging use, let's take the frame of
reference that we need to use something that is cheap and not sought after
so it can be picked up at hamfests for a buck or two.....  The 6CL6 and
the 6CM6 are commonly used, and that might mean that they would not be
so easy to find.  Any other tubes than the 6CL6 or 6CM6?  For some
reason, the 6CL6 has been getting harder to find lately.  I was opting for
something like a 6V6 or 6AG7, although there should be a very common 9 pin
pentode or beam power tube, that is not so hard to find.  Maybe something
from the TV sets such as a 5xxx or such.   I will have to finger through
the RCA manual tonight and see what surfaces.  I am trying to stay away
from sweep tubes and tubes used commonly like the 6CL6 and 12BY7, because
they are being eaten up at hamfests.  There has gotta be a sleeper there
that would be ideal for this kind of thing, and good for glowbugging......

I found the 13EM7 in the TV style tubes that has a standard triode like a
6SN7 and a 10 watt triode companion.  That is one of those ``sleepers''
from the TV era that could prove interesting to work with.....  actually,
even a class A 6SN7 untuned pair (two sections in series) might also work....

But, the chassis has a place for a 9 pin socket already (12AT7 sat there),
so to keep chassis cutting to a minimum, something like a 6BQ5/El-84 might
work (although the audio types eat that one up). 

So.... to continue the discussion, if you had to use an off the wall tube
type, not commonly used in normal ham sets and thus likely to be found in
the junk box at hamfests, what would ring the bells.....

Bob/NA4G

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End of GLOWBUGS Digest 134
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