[TMC] GPR-90RXD stuff

[Richard Knoppow]

    Some more GPR-90 questions.  Because of the previous thread I 
began to read over the various GPR-90 manuals at the TMC site. In 
particular I wanted to know what differences there were between 
the 90 and the 90RXD. I discovered a surprise to me that the RXD 
had a built in product detector. Its activated by the SSB switch 
on the back apron. It has a 6BE6 which operates either as a BFO 
supplying the diode detector or as a product detector taking a 
signal from the IF and connecting to the AF amp. There does not 
seem to be any provision for a  slow release AVC. This is a 
puzzle to me since the receiver is set up to work with an 
external SSB adaptor like the MSR-6 and could work with a more 
comprehensive one like the MSR-9 which has means for connecting 
to a receiver's AVC. So, what was the purpose for this detector? 
Without a slow release AVC it can't have been too satisfactory. 
In addition the IF bandwidth is a little wide for SSB. What was 
going on there?  The receiver has other changes, such as a double 
RF amplifier and perhaps some others. Its a very frustrating 
design to analyze without any idea of the intended market.

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL