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Date: Thu, 19 Nov 2009 19:42:44 +0000
Message-ID: <fc7eccec0911191142x1b33435bie104f1fb36be558@mail.gmail.com>
From: Andy Talbot <andy.g4jnt@googlemail.com>
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: WSPR 2.0 is now available
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Crafty.   'should' be pretty foolproof.   Any old soundcard without
48000Hz ought to just throw-up an error.

Andy
www.g4jnt.com

This email has been scanned for damaging side-effects by the health
and safety police



2009/11/19 Graham <g8fzk@g8fzk.fsnet.co.uk>:
> All
>
> I asked Joe =A0K1JT , this question a short time ago, below is the reply
> G ..
>>
>> Q : Is there a =A0means to
>> compensate =A0for the =A0sound =A0card =A0sampling rate? ,
>
> No, but I think an even better feature. =A0The sample rate in WSPR 2.0=
 will
> always be 48000 Hz. =A0This will prevent a problem that occurs in a few
> systems that insist on sampling at 44100 Hz and then resampling (in the
> driver) to the 12000 Hz requested by WSPR 1.2 ... and doing a *very* poo=
r
> job of the resampling.
>
> --------------------------------------------------
> From: "Andy Talbot" <andy.g4jnt@googlemail.com>
> Sent: Thursday, November 19, 2009 5:29 PM
> To: <rsgb_lf_group@blacksheep.org>
> Subject: Re: LF: WSPR 2.0 is now available
>
>>
>> It has a calibration procedure built in, but as far as I can make out,
>> is aimed at solving frequency offset / tuning errors. =A0 I may have
>> missed something, but there seems to be no facility to calibrate =A0for
>> soundcard errors in the same way as WSJT does, which can affect symbol
>> timing . =A0As we found in discussion on theis reflector a year or so
>> ago. =A0 =A0Sample rate timing error is enough to destroy WSPR decoding
>> even when signals are strong.
>>
>> May be wrong, and will go and re read the appendices associated with
>> calibration, but no mention is made, specifically, of soundcard
>> sampling rate error - only refrences to frequency error.
>> FOrtunately, as WSPR is designed around 12000Hz sampling, this is
>> rarely out by more than a few ppm in most modern cards. =A0 See my
>> Column in the latest RadCom for some soundcard sampling rate
>> measurements - and how bad some are
>>
>>
>> Andy
>> www.g4jnt.com
>>
>> This email has been scanned for damaging side-effects by the health
>> and safety police
>>
>>
>>
>> 2009/11/19 Johan Bodin <jh.bodin@telia.com>:
>>>
>>> =A0http://physics.princeton.edu/pulsar/K1JT/
>>>
>>>
>>> 73
>>> Johan SM6LKM
>>>
>>>
>>>
>>
>>
>
>
>
>