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Date: Sun, 28 Nov 2010 23:02:51 +0100
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Subject: Re: Re2: LF: T/A  [137kHz]  Grabber noisy !
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Hi Markus , Dex , LF ,

Two years ago , I had had the same thing (see pictures) and it had left
at the end of a few days ! I will wait a little to see ? then I will warn=
 !!!
Markus I have a loop of measurement and a sdr + a laptop , and I will
drive out the fox! =E2=80=A6.

73 Jean-Pierre f1afj

Le 28/11/2010 20:45, Markus Vester a =C3=A9crit :
> ...counting the 1ms pixels, the FM rate seems to be about 71 Hz, plus or
> minus soundcard samplerate deviation. Googling for "72 Hz plasma" brough=
t up
> that this is a standard framerate for Pioneer plasma TVs. My assumption=
 is
> that the framerate may be modulating the current consumption, and thus=
 the
> power supply chopper frequency.
>
> Do you have a portable receiver to locate the noise? You may also be abl=
e to
> see the chopper fundamental (eg. ~ 45 kHz ?), by connecting the antenna
> directly to a soundcard with 96 kHz samplerate.
>
> 73, Markus
>
>
> From: Markus Vester
> Sent: Sunday, November 28, 2010 8:03 PM
> To: rsgb_lf_group@blacksheep.org
> Subject: Re: LF: T/A [137kHz] Grabber noisy !
>
>
> Hi Jean Pierre,
>
> on Spectrogram it looks like an FM-modulated source, sweeping between 13=
0
> and 141 kHz, typical for a switched mode power supply harmonic. But the
> strange thing is that the modulation rate is 70 Hz, instead of the usual=
 100
> Hz. Perhaps this could be traced to the frame rate of some monitor or pl=
asma
> TV?
>
> Best 73,
> Markus
>
>
> From: "Jean-Pierre M=C3=A9r=C3=A9 (F1AFJ)"
> Sent: Sunday, November 28, 2010 7:29 PM
> To: rsgb_lf_group@blacksheep.org
> Subject: Re: LF: T/A [137kHz] Grabber noisy !
>
> Hi Roelof ,
> I think that my QRM is local (perhaps CPL) I made capture and an audio
> recording, you can download it here:
> http://jpmere.online.fr/LF/QRM_137kHz/
> 73  Jean-Pierre F1AFJ
>
> Le 28/11/2010 12:07, Roelof Bakker a =C3=A9crit :
>> Hello Jean-Pierre and all,
>>
>> Have you also noted increased wideband noise last night.
>> The band noise faded up and down every few seconds with 6 - 10 dB.
>> I could here it on LF and also on 160m, though less pronounced.
>>
>> It got less as the evening progressed.
>>
>> Any ideas?
>>
>> 73,
>> Roelof Bakker, pa0rdt
>>
>
>
>