Re: LF: WSPR does not work

["Andrey rn3agc" <rn3agc@mail.ru>]

Hello Markus,
Many thanks! Samplerate my sound card 96 khz, deviation 14 hz. I have tried all 
possible variants
of reception which were advised to me by you and other participants 
rsgb-reflector. But the positive
result is not present. Tried to accept also program WSJT7. And I with pleasure 
would try to change
the sound card, but I work with a laptop. I stop attempts of reception WSPR 
until then when there
will be a possibility to experiment with other computer.

73
Andrey RN3AGC in KO85SV



> Hi Andrey,
>
> this has been mentioned before - have you checked your ADC samplerate? See 
> http://www.wsprnet.org/drupal/node/339. If tx and rx
> samplerate deviated by say only 0.3% (ie. 36 Hz from 12 kHz), the bit timing would have shifted by half a symbol duration at the 
> end
> of the 162 bit message. I started having doubts about my own DAC rate when 
> Graham reported negative decoding, but the TX audio
> frequency seems to be correct to within a fraction of a Hz. You could roughly check the rx samplerate by injecting a known 1.5 
> kHz
> tone and use WSPR spectrogram which resolves ~ 0.1%. Regarding other digital modes, I recall that samplerate was very critical 
> for
> WOLF which relies on a coherent bit frame over a long integration period. On 
> the other hand, it's not much of an issue for PSK31
> which is "freerunning" only for a few symbols.
>
> The maximum tolerable PC clock error between tx and rx seems to be 2.2 seconds. This was the last displayed dt offset before I 
> lost
> track of Jim's consistent signal the other morning. My PC clock is slightly 
> slow and would need resetting more often. But you
> mentioned you have that under tight control.
>
> The WSPR program does not seem to be disturbed or overloaded by strong out-of 
> band signals. Inserting a 200 Hz filter before the
> decoder made no difference at all, even though the total audio power was reduced by 20 or 30 dB. I also did not see any 
> degradation
> when I used very low audio levels. The WSPR spectrogram seems to have a display 
> leveling similar to the Argo AGC option, as the
> colours do not change when the audio gain is varied.
>
> Best wishes
> Markus, DF6NM
>
> ----- Original Message ----- 
> From: "Andrey rn3agc" <rn3agc@mail.ru>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Friday, January 16, 2009 8:56 PM
> Subject: Re: LF: WSPR does not work
>
>
> Hello Johan, James, LF,
> Many thanks for the help! Yesterday WSPR-signal DF6NM
> passed here from time to time much more strongly, than the day
> before yesterday. But decoding still was not. I have installed WSJT7.
> If again the result is negative, the problem most likely in a sound card
> means. Though to this case without problems decoded any amateur
> digital protocols.
>
> 73
> Andrey RN3AGC in KO85SV