[Amps] Transceivers

[Will Matney]

Peter,
This very technique was used by Yaesu in several tube transceivers I've 
found. It was shown in the book, "Understanding Radio" by the Untied 
States Armed Forces Institute, published in 1940 and 1951 by McGraw 
Hill. In the book, it mainly described using triodes in the circuit 
where Yaesu mainly used dual tubes having a triode and a pentode (6U8) 
as the receive mixer. The pentodes G1 was driven by the output of the 
oscillator. There were some military receivers using similar circuitry 
which I have the schematics here. This is the very information I am 
looking for. Thanks for the input.

Will Matney

peter.chadwick at Zarlink.Com wrote:

>
> Bill said:
>
> >But if  the local oscillator signal  is strong enough to simply turn 
> on and off the mixer tube it does become a very effective >frequency 
> mixer.  It then appears to be an analog mixer multiplying a signal 
> with a square wave.
>
> It does reduce the conversion gain, though. That's the big problem 
> with switching mixers. The so called 'Gilbert cell' (which Barrie 
> Gilbert doesn't claim as his -  it was first patented by a guy from 
> RCA as a 4 quadrant multiplier -  Barrie's claim is that he was the 
> first to suggest using it as a mixer, and even that's disputed) can be 
> oeprated in lower gain as a switching mixer, and in higher gain as an 
> analogue multiplier type mixer, with lower LO drive and worse IMD 
> performance. It also is more susceptible to AM on the LO.
>
> 73
>
> Peter G3RZP.