[Lowfer] WSPR for Dec.14-15

[Eric NO3M]

John

It seems like there might be sidebands getting produced with 
strong signals in your RX chain somewhere.  WE2XGR/2 triggered a 
few also:

2012-12-15 06:16 	 WE2XGR/2 	 0.475622 	 +3 	 0 	 FN31ls 	 20 	 
VE3EAR
2012-12-15 06:16 	 WE2XGR/2 	 0.475687 	 -27 	 0 	 FN31ls 	 20 	 
VE3EAR

additional double decodes at 09:54, 10:14.  I think our proximity 
and higher signal level made the situation more pronounced, up to 
4 sideband decodes per session in addition to the primary signal.

I doubt it's something in the TS-440 unless there is a mixing 
problem that's creating close-in sidebands.  You might try 
adjusting audio levels between TS440 -> DSP and DSP -> Soundcard, 
while maintaining a non-signal noise level of 0dB (+/- a few dB) 
in the WSPR software (set with radio on a clear freq.).  If you 
are using WSPR 2.21, you might have to knock the audio down even 
further than with WSPR 2.11.  I've noticed the newer version 
reports much higher noise levels at the same audio settings when 
adjusted correctly for the old version.

If you are using a pre-amp ahead of the TS440, that may be 
another potential contributor when exposed to strong in-band signals.

73 - Eric NO3M, WG2XJM


On 12/15/12 15:41, John Bruce McCreath wrote:
> Hi Eric, Lowfers,
>
> I could very well have a problem here.  From the beginning, my WSPR decodes have been prone to displaying "false stations".
> This happens on both 600 M and 2200 M, where the only difference in the setup is the antenna.  The balance of the chain is
> my TS-440, a Timewave DSP filter, an audio isolation transformer and the SoundBlaster audio card in the older Pentium II.
> The settings on the DSP filter are to create a passband from 1300 to 1700 Hz.  Maybe I should make the window wider?
>
> I have logged trans Atlantic decodes from several European and UK stations, so the setup certainly does work for me, but I'd
> be really pleased if I could resolve the false decodes problem.  Because of them, I've been reluctant to upload the spots to
> the WSPR web site unless I'm here in the shack to keep an eye on it.  I'm open to any suggestions you may have.
>
> 73, J.B., VE3EAR
>
> LowFER Beacon "EAR"
> 188.830 kHz. QRSS30
> EN93dr
>
>
>
>
>