[Lowfer] 474.2 kHz WSPR false decodes

[JD]

>>> Others have reported decodes for the same callsign but some of them are 
>>> for 2 frequencies simultaneously and overall the frequency given varies 
>>> wildly.

Sometimes I get decodes of a station on two frequencies simultaneously, but 
here it's almost always the case that they are 120 Hz apart, with the 
spurious one between 20 and 30 dB down from the other...usually a hum 
sideband caused by a ground loop at the transmitting station.  I like to run 
Argo captures of the band simultaneously with WSPR so I can go back and look 
for signs of hum and intermod products when odd decodes turn up.