[Boatanchors] new on list with old gear

Wed Sep 5 21:04:28 EDT 2018

   The help here is very encouraging, I'd like to restore it.  A little
information about myself.

   Licenced in 1970, got on the air with a 19 set, then a borrowed DX60
until my Dad and I built an HW 101.  After leaving home there were gaps
in my activity, but I didn't wander far.  Bought, and still have, a Ten
Ten Omni A (1980), with the VFO.  I've built a R2Pro receiver and have
some familiarity with phasing SSB generation and direct conversion
receivers, which makes the 20A that much more interesting as its like a
grandfather to what I've been working with.

   My background is avionics, a bench tech since 1980, doing more
installation and line maintenance now.

   My XYL Laura is VE8LT, and my youngest son is Nathan VE8TN.

   I have a few boxes of vacuum tubes, a couple of tube testers, and a
better than basic service bench at home.

   This year I turned 63, I'd like to put together a period station to
use in my retirement.  I'd also like to find the right people to pass
on any vintage gear of value to before I become a SK myself.

   As I hadn't set out to take on this project, I'm glad it came
along.  On Saturday I woke up to the honking of geese flying south, it
was +2C outside.  This morning it was snowing.  This new to me
gear gave got me thinking about operating during the winter
with some warmth and dim light coming from the vacuum tube gear.  My
equivalent of keeping warm by the fireplace (which I don't have :-( 

 Perhaps hard to understand if you're used to warmer regions, but I like
it here, and for the last couple of years have put in at least a mile
and half walk outdoors, regardless of the weather, during my lunch
break (really want to retire in good health if possible :-)

   There is no rush to get these on the air.  I may try to pair them up
with the R2Pro, but it would be nice to eventually acquire a
receiver from the same time.

   Ron VE8RT

On Wed, 5 Sep 2018 19:11:55 -0500
Robert Nickels <ranickel at comcast.net> wrote:

> On 9/5/2018 6:28 PM, Ron VE8RT wrote:
> >     With respect to the Central Electronics 20A, my suspicion is that
> > this was a kit that could be built without phone capability.  The
> > components and controls for phone operation are missing.
> 
> Rich,
> 
> The 20A is one of the first commercial SSB transmitters from the 1950s, 
> and played a major role in popularizing SSB.  It's a classic and 
> deserves restoration and hopefully use on the air, where it will rival 
> the audio quality of  any rig.
> 
> But you should begin by reading the manual so you understand what you 
> have and  how it works.    You can download it here: 
> http://bama.edebris.com/manuals/ce/
> 
> Basically,  the 20A is a heterodyne exciter that requires an external 
> VFO or signal source, or a crystal for a specific frequency.  Since it 
> generates SSB (or AM or PM) on 9 MHz, the frequency of the external VFO 
> must be able to mix with that to produce the desired output frequency.  
> The easiest solution is to use a VFO that tune in the 5 MHz range which 
> will cover 80 meters (9 minus 5) and 20 meters (9 plus 5).   This is why 
> you'll see that a Command Set transmitter which was available cheaply on 
> the surplus market at the time was commonly used, and Central sold a kit 
> that added circuitry to cover the other amateur bands.   Those VFOs were 
> quite good but not perfect, but nowadays a digital synthesizer with the 
> required output level can be used for stability on par with any modern rig.
> 
> The output of the 20A is typically 15-20 watts, which is plenty to drive 
> a linear, as it was intended to do.   But I've made lots of contacts 
> with a"barefoot" 20A.    Properly adjusted they will make very 
> good-sounding AM as well as SSB.
> 
> You're right in that the 20A was sold both as a kit and factory wired, 
> but everything required for AM, PM, and SSB phone operation was 
> included.   If you noticed an empty octal socket in the middle of the 
> chassis,  that's for the QT-1 which was an optional anti-trip unit for 
> VOX operation with a loudspeaker.    Be sure the other plug-in module 
> that's halfway back on the left-hand side which is labelled "PS-1" is 
> present, because the transmitter won't work without it.
> 
> Hope this helps, as you can probably guess I love the 20A! There's a 
> separate list just for Central Electronics gear and lots of help 
> available if you need it.
> 
> 73, Bob W9RAN
> 
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-- 
Ron VE8RT <ve8rt at yknwt.ca>