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Date: Sat, 17 Jan 2009 22:48:18 +0100
From: =?ISO-8859-1?Q?Wolfgang_B=FCscher?= <dl4yhf@freenet.de>
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Subject: Re: LF: RE: F5WK WSPR
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Hi Gary, Jim, and all,

Gary wrote:

> Michel (F5WK) is now almost not seen on the WSPR & SpecLab display but the
> signal is decoding fine. With the current settings I have reduced the
> received signal strength but both are decoding no problem.
>
> Earlier in the evening Michel's signal was quite strong on both displays but
> no decode.
>
> I have set the Rx to SSB, 500Hz filter & external tuned  pre-amp to moderate
> gain. The antenna is Mini-Whip.
>
>   
Inspired by this, I switched one of the TS 850's IF filter from 2.7 kHz 
to 500 Hz, and centered it on 1500 Hz audio (which is possible in SSB 
with the passband tuning knob). Expected a better SNR because there's 
plenty of QRM around here, but :

(a few decodes with full 2.7 kHz SSB bandwidth) :
2128 -21  0.0   0.137577  0 F5WK JN18 37
2130 -20 -0.2   0.137500  0 M0BMU IO91 23
(now switched to 500 Hz audio BW, around 1500 Hz center)
2134 -26  0.0   0.137577  0 F5WK JN18 37

An SNR *drop* of 5 dB (for F5WK) within 6 minutes; don't think this is 
caused by "propagation".

Apart from that, I never had a "zero" offset for the DT parameter, so 
apparently Michel must have a very precise time reference. Or it's just 
coincidence.

Will switch back to 2.7 kHz bandwidth now to check if the SNR values 
increase again.

Cheers,
  Wolf .