2013/1/22 Roger Lapthorn <[email protected]>:
> Now, to me these figures seem far too low, so perhaps the noise level is
> much higher than 3uV/m or my maths are wrong?


The noise floor is variable (over time) and the noise in WSPR S/N is
calculated on a 2500 Hz window that may contain all sorts of RF
garbage that come and go and will influence the noise calculation.

I think WSPR reports are good for relative comparisons between
multiple reception reports of the same transmitter at the same
receiver. Even then, a plasma TV or a  CFL may be turned on or off,
and that may affect the S/N reported.


73, Dimitris VK1SV