WSPR reports vs VOACAP predicted values

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f6irf's picture
Last seen: 12 years 7 months ago
Joined: 2008/04/18 - 12:24
WSPR reports vs VOACAP predicted values

I have posted a few charts on my blog which show quite important differences between the WSPR reported values and the VOACAP predicted values. It is based on temporary data (April 1st to 20 on 30m) on a particular path (F6IRF>W1BW). While the bands openings/closures seem to match quite closely the predicted values, there is an important difference (16~20dB), between the predicted SNR and the reported ones. I have used various "required reliability", methods (20, 22 and 30), absorption model, coefficients and SSN values, but still the difference remains... Of course there is a certain number of uncertain parameters, but I do not believe that my vertical has 16dBi gain !
I will repeat the same with other pathes, with a higher number of spots, but in the meantime I would be interested to know if anybody has already done such comparisons, or has an ideas on what could cause such an offset !
Regards - Patrick