[hpsdr] Munin Problems Update

[John]

Today I connected a UHF directional coupler between the output of 
Alex (fed by Munin) and the antenna system.   The antenna system 
antenna coupler was previously adjusted adjusted for low SWR with 
another rig.  The reflected output of the UHF coupler was attached to 
an oscilloscope.

With PowerHPSDR drive level 4 on 3.574 mHz about 15 Watts output is 
indicated on PowerHPSDR with a high SWR.   The scope showed a nice 
looking sine wave of about 5.26 mHz when the rig was keyed in CW mode.

When the output of Alex was moved to a 50 Ohm load PowerHPSDR 
indicted 8.0 Watts forward power and there was about 1mV p-p 
reflected voltage at the coupler (not enough to sync my scope or 
check frequency).  Reversing the coupler to measure forward power, 
still with 50 Ohm load showed a signal of about 3.7 mHz (probably 
exact Hermes frequency).

When checking reflected power with the antenna at 1.820 mHz the scope 
waveform displayed was roughly 2.63 mHz (about half the spurious 
frequency when driven on 80m).

When checking as 50 mHz the reflected power waveform was roughly 909 kHz.

At all three frequencies checked this way, when the load was 50 Ohms 
PowerHPSDR indicated a low SWR.  However, at 50 mHz with 50 Ohms 
there was about 9 mV p-p reflected power at 50 mHz.  I think this is 
because the coupling I measured was only -42.15 dB at 50.1 mHz, 
-65.36 dB at 3.5, and -71.08 dB at 1.8 mHz.

Apparently my Munin is very sensitive to the load connected to Alex.

At this point I'm ready to take a break and try my luck at working 
South Dakota on the low bands.  :^)

John,  WoGN