The change from 500KHz to 472KHz rendered a few mini Xtal controlled TX modules once used on 500 redundant so I have changed them to DDS control.
I have run the 200uW TX again which gave me my first spot on 500kHz in 20009 :-
2009-11-22 00:48 G3ZJO 0.503814 -30 0 IO92ng +17 0.050 M0BMU IO91vr 76 47
Since that first report I have made antenna improvements so assuming no changes at M0BMU these should be reflected in the report from that rig.
2013-01-28 00:50 G3ZJO 0.475790 -18 0 IO92ng +0 0.001 M0BMU IO91vr 76 47
Last night I ran a different mixer/driver to the same PA still 200uW EIRP with very much the same results.
2013-01-30 00:30 G3ZJO 0.475612 -21 0 IO92ng +0 0.001 M0BMU IO91vr 76 47
Today I completed the change of my very first test TX into a buffer, this TX could never produce enough signal into my first antenna experiments for a decode. I measured the power into a 50R load it is 10dB down on the above TX so 20uW EIRP. I tried it as the PA.
Smaller than the average MF PA this postage stamp size device produced predictable results. Low component count, the SMD chip is under the Veroboard, the LPF is in line to the antenna.
2013-01-31 14:46 G3ZJO 0.475601 -30 0 IO92ng +0 0.001 M0BMU IO91vr 76 47
After 4 transmissions (only 8 minutes on air) my best DX is 100Km.
2013-01-31 14:56 G3ZJO 0.475602 -29 0 IO92ng +0 0.001 G3SZS IO81vv 100 62
If I was calling CQ on the key I estimate 8000 Years before I got any report AT ALL.
Unfortunately the power levels shown by the WSPR reports are not correct and must be disregarded.