Some spectrum plots of the WSPR signal can be seen at

   http://www.g4jnt.com/wspr-spectra/

These were generated at 1500Hz using WSPR.EXE, directly converted to
RF and fed via an attenuator to an SDR-IQ for measuring and displaying
the spectrum.

If we use the widely accepted -40dBc criteria for adjacent channel
spurii, then it is clear the transmission can be centred at up to 10Hz
below the upper band edge.


Andy  G4JNT
www.g4jnt.com



2009/1/26 Graham <[email protected]>:
>
> Are we to  adopt  502.400 Hz  USB dial frequency for WSPR ?
> With  1500 Hz audio centre band tone.
>
> RF mid band   carrier frequency of  503.900 Hz ?
>
> With 6 hz modulation and phase continues  tone side bands and
> guard band are  not a issue, the band edge is protected?
>
> 504KHz  and its sidebands are actually  x2 of the fundamental
> so  should not present a problem as the 200 Hz slot is in a
> close in, dead zone, there amplitude increasing lower into the band,
> one of the reasons qrss and range testing takes place in this
> 'noisy' zone.
>
> I will add a  note to  the uk500khz group and links in others  with details
> if
> acceptable to widen the reporting base.
>
> Tnx-
>
> Graham
>
> G0NBD
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