On 4 Mar 2012, at 12:08CET, Stefan Schäfer wrote:

> Hi John,
> 
> Any further details or a screenshot?

Unfortunately not. I had just come into the shack and noticed your call sign 
disappearing off the Argo display.  From the contrast I would guess that it was 
between 30 and 40dB over the noise, but I did not have time to measure it.

I now have the monitoring receiver running again, with usually two invocations 
of Argo looking at different aspects of 137. I have looked at monitoring WSPR 
simultaneously, which is possible when the required receiver audio output 
frequency is 1500 Hz, but when people work at the lower end of the band I have 
to retune and I can then no longer satisfactorily display the higher 
frequencies.

You recently mentioned that you were using an H-Bridge amplifier for 137, but I 
seem to have lost the details. Could you post them again, please? I am finding 
that I am rather good at blowing up class E PAs and think I should look for 
something that is rather more robust (and more tolerant of variations in load  
isimpedance).

73
John F5VLF