[hpsdr] Using Mercury to monitor final amplifier transmit signal

[Tom Cathey]

Thanks much for the indo, Joe and Phil!


i usually use a resistive divider to tap down from the 50 ohm line. With a 4 
position switch, anywhere from 2K to 50K non-inductive  will give a good 
sample when running from 10 to 1 KW.

The duplex mode - I'll do some reading on that too.


So, when we presently transmit in the stock mode using Merc and Penny, the 
sampled RF we see on the screen is stray feedthru - I didn't know that. 
The problem with watching this low level signal is it gives us a false sense 
of a clean signal - when in reality, the final amplifier could be tearing up 
the band... :-)


Appreciate the help.

Oh, BTW, remember the problem I had with Mercury locking up when Penny was 
unkeyed?  I stuggled for a year trying to find the problem.  Turns out that 
I have about 25 relays in the shack for different applications. Some of them 
did NOT have diode dampers across the relay coils. I was being lazy.  This 
caused an EMF spike on unkey.  After adding diodes to all relays, the spike 
has been cut way down  and I haven't had a Merc lock up once. There is still 
a residual spike, but Mercury has not lost its mind once.

I also got rid of the LPU power supply unit and and used Sola supplies for 
+ - 12V and 5V.    Not sure if that helped, but was part of the shotgun fix 
approach.   I plan to try Hermes in the future too.

Later -

Tom, K1JJ





 1360257015.0