Just received my first WSPR signal on 500kHz - from SM6BHZ running 1W erp. Signal first appeared at 1916z and was decoded 6 minutes later. This is a screen shot of his signals. Several other stations are also copying Gus if you look on the WSPR database and maps tonight. Later in the evening he was so strong he could have been copied with just 2mW ERP.
I also copied another 500kHz WSPR signal, this time from G4WGT who was -23dB S/N with 500mW ERP from IO83 at 248kms. The map shows stations active on TX or listening and shows I've received SM6BHZ and G4WGT. Very clever database this!
Later still copied M0BMU and G4WGT again on 500kHz WSPR.