On the 12th of May 2009 I spotted a strange wide signal on WSPR.
At first DL6NL and I thought it could be a new home brew WSPR TX not yet adjusted correctly. I checked the exact width of the signal and found it to be exactly double the correct deviation. Unlikely I think that someone capable of producing his own system would adjust to precisely double.
One way to achieve this would be to use a system which used a doubler on the correct WSPR signal to reach the desired transmit frequency.
F6IRF has recently seen the signal again, it seems to be the same signature, the mystery deepens, does this operator know what he is doing, surely he has never had a decode.
