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Date: Fri, 30 Nov 2012 18:08:57 +0100
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: WSJT-X v0.5 r2788
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Thanks Joe,

Well, the QRN on LF is quite different to that on HF. So probably the=20
optimised parameter settings (to be found) will be quite different as=20
well. As a spontan idea, maybe the program should allow to choose the=20
band which we are receiving on and the program will use specific NB=20
settings, different on LF compared to HF.
For serious (serious is relative) LF DX, JT9-10 and JT9-30 will be=20
preferred, also in contrast to HF. So i think i'll go on in these modes=20
and RX stations may collect some wav recordings for future anylysis.=20
I'll enable "Save all" as well here.

I'll try to run WSJT-X at YV7MAE in FK81BD as well, this night in=20
JT9-30. It may be a bit to optimistic to expect a decode though.

73, Stefan/DK7FC

PS: Another idea: If there are some RX stations who like to do some=20
tests, we could try to run 2 instances of WSJT-X, one with and one=20
without the NB. Maybe it requires to install the program twice, in=20
separate folders


Am 30.11.2012 17:35, schrieb Joe Taylor:
> Hi Stefan
>
> On 11/30/2012 11:00 AM, Stefan Sch=E4fer wrote:
>> Hi Joe/K1JT,
>>
>> A general question to the NB: What do you think about its performance =
in
>> the current state? Normally NB is disabled when starting the program.
>> Applying a NB to "remove" QRN makes a big effect on LF, you know.
>> Is there an estimation like 2 dB improvement or so?
>
> So far I have spent very little time testing or optimizing the WSJT-X=20
> noise blanker.
>
> Here are some relevant examples from a week ago on 80 meters.  The=20
> same recorded raw data has been decoded twice using WSJT-X r2788. =20
> Everything was the same for the two cases, except for switching NB OFF=20
> or ON.
>
>  UTC  Sync dB    DT   Freq  Drift Message
> -------------------------------------------------
> 2156   5  -26   0.3   1349.  -1   K1JT G0MGM -09   (NB OFF)
> 2158   4  -25   0.2   1349.   0   K1JT G0MGM RRR   (NB OFF)
>
> 2156   9  -22   0.3   1349.  -1   K1JT G0MGM -09   (NB ON)
> 2158   4  -22   0.2   1349.   0   K1JT G0MGM RRR   (NB ON)
>
> 2200   4  -22   0.1   1346.   1   K1JT I3VWK JN55  (NB OFF)
> 2200   5  -21   0.1   1346.   1   K1JT I3VWK JN55  (NB ON)
>
> Although there's some suggestion that the present noise blanker can=20
> improve S/N by 1 to 4 dB, this is hardly a definitive result.
>
> If you have some useful example files with a marginal JT9 signal and=20
> heavy QRN, please send them along!  I may find some time to work on=20
> the noise blanker soon.
>
>     -- 73, Joe, K1JT
>
> PS: alas, I listened for your LF signal on 137.42 last night, but did=20
> not copy anything.
>
>