Re: Tracing receive signal for low signal

Dave Space
 

Just to see if using coax would have changed other numbers on the signal generator
I retested (I might have measured wrong before) input took 700uV in at the antenna got to 100mv peak to peak at vol high same as recently with my pre-amp installed. So no difference with coax at that location.

As mentioned before while it seemed there was crazy loading when I used higher voltage like 700mv it had more difference than Evans board (though he input at only 500mv). 
Inputting at lower voltage at the antenna at 30mv @ 7.147MHZ I got about 14-16mv out at TP1.  Removing my jumper and injecting at the K1 side it was just slightly more at L4 maybe 15-18mv.  So the K3 relay doesn't seem to have a huge effect.  

So given there doesn't seem to be any significant loading there.  So don't think it makes sense to cut the trace to the mixer anymore right to test?

Evans board seems to match a lot of the voltage levels on parts so seems like something else is up perhaps.
It seems like we do know with enough power things will work... so potentially could just add amplifier stages after Q12 and after Q32 would likely workaround the rather anemic receive?  

(Diagnostics definitely seem harder when things sort of work just not quite as well as you'd like... especially when the measurements are in microvolts that most instruments won't be able to measure well with all the noise in the system/on the board... and using larger voltages for some reason is inducing more loading as per the earlier measurements.)

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