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Date: Wed, 07 Sep 2011 23:59:39 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: Effects of noise burst
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Hi Bill,

I think the other traces disappear because the AGC is enabled?

BTW your trace at 136.170 kHz may reduce the S/N of the wanted signal 
since it affects the noiseblanker treshold. So better switch it OFF or 
reduce it to 10 dB S/N or so.

Just started to TX in QRSS-60, transmitting until arround 6 UTC here...

73 es good luck.

Stefan/DK7FC

Am 07.09.2011 23:24, schrieb Bill de Carle:
> I noticed my marker line was getting chopped up at times on both 
> Spectrum Lab screens.  At first I thought it was another strong 
> carrier off-screen for the SL display but still within the 500-Hz Cw 
> filter's passband.  There are several clearly *audible* signals in 
> there at times.  So I brought up ARGO for a wider view using 3-second 
> dot mode.  You can see my marker at 136.170 Khz along with several 
> other much stronger signals.  Around the middle of the time grab it 
> seems as if everything went dead - in fact it was a 45-second burst of 
> local noise.  Not much of anything audible but I saw the S-meter jump 
> up about 30 dB (cutting back the RF gain and making the other weaker 
> signals disappear).  Interesting how the background looks exactly the 
> same during the noise burst as at other times.  We don't *see* any 
> noise here, we see the *absence* of all the usual signals.  That noise 
> is what chops up my marker lines on the two .usr spectrum lab 
> screens.  Although still full daylight here it's getting near supper 
> time and people are turning on appliances.  Things will quiet down 
> later hopefully.  Here's the ARGO screen:
>
> http://www.nrtco.net/~ve2iq/grabs/136argo.jpg
>
> Bill, VE2IQ
>