Over the last 2 weeks, I received 19 unique spots on 472kHz WSPR using my 5mW ERP from the earth-electrode "antenna". On RX I spotted a total of 23 unique stations. Most were without a preamp and on the deaf FT817. On RX I have still to carefully analyse the Excel data supplied by Bert, but the impression is that the RX preamp helps the copy of very weak signals but has not (so far) enabled me to copy and decode more stations. This is the breakdown.
My 5mW ERP was copied as follows:
3 Germany - DL-SWL and DL-SWL/1 - best DX at 701km
On RX I copied the following unique stations (most copied many times):
1 Spain - best DX is EA5DOM at 1525km