[HBR] RSGB Keyer: I QUIT!!!

[MARSHALL DUES]

Eddy,

I recently came across an old QST magazine from October, 1958, that
has a very similar keyer to the
RSGB keyer, except this one does not have a relay to key the
transmitter -- it has a vacuum tube keying
stage to replace the relay.  There was not a lot of circuit
description in the text, but the schematic has a
tube like a 6AS7, I believe, as the keyer .  The front end, however,
was just like the RSGB circuit, in that
the B+ supply was at ground potential for the plates, with the
cathodes at negative potential so no high
voltage would appear on the paddle switch contacts.  Also, it had an
audio transformer connected in the
same manner, and it used two 12AU7s or 12AT7s before the 6AS7 output
stage.  I will see if I can find
and copy the article for you soon if you would like to see it.

Regards

Marshall Dues, K5MMD
Katy, Texas



On Tue, May 27, 2008 at 9:47 AM, EP Swynar <gswynar at durham.net> wrote:
> Good Day All,
>
> Well, that's it...!
>
> I'm through fooling around with the single 12AT7 RSGB keyer that I've been
> working on here, lo these past many months...
>
> http://www.flickr.com/photos/15888272@N05/?saved=1
>
> I simply can NOT get the doggone thing to oscillate, try as I might...
>
> I located a dandy old Hammond interstage audio transformer --- with a
> 10,500-ohm centre-tapped wiring --- and thought that would do the trick, in
> the absence of a push-pull audio output transformer...no dice. I then
> checked, & RE-checked, my wiring...nothing. I replaced the capacitor
> (smaller, bigger, & in- between)...zippo. I checked the value of the
> components, the voltages, etc. etc. ad nauseam...zilch.
>
> Sometimes what appears to be the simplest of circuits / projects, brings
> with it the biggest chance of complete & utter failure, I guess!
>
> The ONLY time that I could get the darned mercury wetted relay to close was
> when I had the weight control set near one end of its maximum travel --- but
> that area of the circuit isn't even a part of the oscillator itself, anyway
> (sigh!).
>
> Oh well --- I still have my trusty old Vibroplex Presentation bug to key the
> Drake Twins...and I suppose I could always salvage the enclosure, such as it
> is, for some other project, as yet to be...
>
> ~73!~ Eddy VE3CUI - VE3XZ
>
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