With just a single spot all day on 6m from a station 33km away, I have left the 10m beacon still running (still Es about) and QSYed from 6m to 630m WSPR with the earth-electrode "antenna". In recent days 630m has not been brilliant.
UPDATE 1915z: PA3ABK/2 (306km) being spotted on 630m (472kHz) WSPR.
UPDATE 2256z: On 10m WSPR I have been reported at incredible strength (+4dB) by DF4UE (758km) when running 500mW. This implies he would copy me at uW levels!