[R-390] R-390A sensitivity measurements

[DJED1 at aol.com]

Thanks for the note, Bob.   I went with the instructions in the URM-25 
manual, which clearly intend that there be a 50 ohm load on the generator for the 
output voltage to be equal to the meter reading.   I was reminded of this when i 
put my scope on the HP generator to check the output- way off until I put a 
50 ohm termination on the etup, then the generator output was right on.   So 
I'm convinced that the generator needs to be terminated properly.   Of course 
this is not a problem for 50 ohm receivers.   For the R-390, it troubles me that 
we don't have an impedance match between the generator and the radio, but we 
do know, I submit, the voltage across the receiver terminals.   If you wanted 
to determine the power going into the receiver, I would use the 125 ohm value 
and the measured voltage.   Probably the best way is to devise a lossless 
transformer to go from 50 ohms to 125 ohms.   I haven't tried to do that yet, but 
I'm working on it.
Regards, Ed