[Boatanchors] Re: old homebrew rigs

[N5CM@aol.com]

Hi Dave & Gang,

Speaking of homebrew rigs, have any of you heard of an oscillator circuit 
called a,
"Pull-Pull" oscillator????
Back in the spring of 1938 when I got my first ham ticket, W5HHA, I ran 
across the circuit in a publication and built it up....I cannot remember the 
publication and thought it was QST but haven't been able to locate it....
It resembled the "Tuned Grid Tuned Plate Oscillator", the difference being 
that the feedback coil wound over the plate coil was wound backwards.
He theorized that a change in plate current with varying load (Keying CW) 
caused a change in the field which induced a change in the feedback winding 
but in reverse polarity causing the two pulling in opposite directions to 
lock together holding the frequency steady (Pull-Pull)....
I can vouch that it was as stable as any crystal controlled xmtr....I never 
got less than a T9x report on 20 CW....
I would like to build up the little one tube xmtr again - if anyone has a 
type 47 tube, I would like to buy it....That was the only tube I had that was 
rated with reasonable output - was an audio output in some of the early 
"electric sets"....

Ken....N5CM....NNN0FKQ.... 



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