1 Jun 2014

Doppler on 6m with G4IKZ (18km)

There must be more local flying activity at Cambridge Airport on Sundays (private flying?). On my 6m 1624z transmission there was 3Hz Doppler noticeable at G4IKZ - quite a bit when usually I get none at all. For a WSPR signal to be heard, the direct signal has usually to be much stronger than the Doppler shifted signal otherwise WSPR will not usually decode properly. Usually aircraft directions in flight have to be such that no Doppler is apparent for aircraft refection to work as a "path enhancer". I have noticed this with G3WKW in Hampshire on 144MHz WSPR over what is quite a long path. Get just the right flight direction and decodes occur. Otherwise, strong signals and no decodes. Sometimes G3WKW has been there for hours before he decodes on 144MHz.

G0LRD (25km) is just coming in on 6m at 1638z  at a strong -8 dB S/N with -4Hz Doppler, so his signal is arriving off an aircraft currently.

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