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Re: LF: WSPRX_08r3575

To: [email protected]
Subject: Re: LF: WSPRX_08r3575
From: Stefan Schäfer <[email protected]>
Date: Thu, 03 Oct 2013 21:08:42 +0200
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G

4X1RF and GW0EZY took a recording of my WSPR transmission and sent it to me via dropbox, a wav file recorded in SpecLab.

I run the recordings in an endless loop and produced a set of decodes, 5 decodes for each setting, just to make sure that there is no random difference in the S/N shown for the same settings. Mostly the S/N shown was the same for a certain setting, maybe 1 of 5 differed by 1 dB. The results were quite clear. I've done the test with strong signals (GW0EZY) and weak signals (4X1RF). There average improvement was 2 dB, maybe a bit more.

73, Stefan

Am 03.10.2013 20:45, schrieb Graham:
How did  you  measure the  2 dB  Stefan ?

--------------------------------------------------
From: "Stefan Schäfer" <[email protected]>
Sent: Thursday, October 03, 2013 6:47 PM
To: <[email protected]>
Subject: Re: LF: WSPRX_08r3575

Hi Tobias,

Am 02.10.2013 16:19, schrieb Tobias DG3LV:
Hi Stefan/LF !

Information on the SVN-server says, that there was a noise blanker added.

Thanks for all the infos.
Finally :-) During the time he developed WSPR-15 we were in regular email contact. To that time i made some tests with DF6NM's slow WSPR version, tests with 4X1RF and GW0EZY and others. We found that the SpecLab noise blanker in front of the WSPR input (using VAC) made a S/N improvement of at least 2 dB. Obviously he anyway didn't include such a tool (which is much more useful on LF/MF as on the HF bands i think) in the previous versions.

Now the question is if the new intenal NB is more efficient than an external SpecLab NB. One could do a test running 4 WSPR-x instances, the old one, with and without a SpecLab NB and then the new one, with and without a SpecLab NB... If the new one without a SpecLab NB performs best, then this would be really an improvement over the older version! If i can find the time i will do such a test at night.

73, Stefan/DK7FC




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