[Milsurplus] 958 Acorn Tube Char. Charts?

[David Ross]

Dave & the gang -

  OK on the proposed TBY mod -  hopefully you can get some sort of
amnesty deal on the War Crimes rap, given that it is such a worthwhile
mod & also that the changes are trivial.

  The TBY TX is a pair of 958A acorn tubes in a push-pull modulated
oscillator, filament voltage is 1.5VDC and as I recall there is a "C"
bias voltage of -7.5VDC.  That 9VDC might work as VCC for a CMOS digital
IC -  if you could get a 74HC74 to clock at 56.XXX MCS, it's Q & /Q
outputs would give you appropriate 10 meter push-pull drive for those
smokin' 958As.

  Someone posted several links to acorn tube info yesterday -  thanks. 
Fascinating to note that some 958s in oscillator circuits would continue
to oscillate even after filament voltage was removed -  see the link at:
http://www.antiquewireless.org/otb/acorntube.htm
  From that page:
> In 1942 the 958 received tighter controls on
> emission and became the 958A. This was in
> response to a report from the Navy that, in
> one of their transmitters -- possibly an early
> model of the TBY -- the tube kept oscillating
> even after filament power was turned off.
> Filaments with unusually high emission could
> keep going, heated only by the plate current.

  Good luck with the TBY work Dave, please keep the group posted re your
progress.

best 73
Dave Ross    N7EPI    ross@hypertools.com