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Re: LF: Argo vs SpecLab - DCF39 bursts

To: <[email protected]>
Subject: Re: LF: Argo vs SpecLab - DCF39 bursts
From: "Markus Vester" <[email protected]>
Date: Sat, 7 Apr 2012 12:25:06 +0200
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Hi Mike,
 
you have probably selected Argo's visual AGC button on the bottom left, which is on by default. This does not really suppress interference, but scales each display column to the same average brightness of the noise. So during a strong noise burst, the brightness stays the same but the signals disappear.
 
Speclab also has a similar visual AGC option. The advantage is that you wouldn't have to adjust gain between day and night, but I rarely use it because I like to see whether the signal went down or the noise went up. 
 
As you can guess, DCF (and also HGA) sidebands are really big here. For the LF grabber I am using neither analog or digital AGC nor clipper, just the SpecLab noise blanker alone. It gets the full SSB bandwidth and is set to fast rampdown / rampup times (2 ms), so that it can recover between individual clicks within an FSK bursts, minimizing signal loss. The NB threshold is normally set to 9 dB above average.
 
Best wishes,
Markus (DF6NM)
 
 
Sent: Saturday, April 07, 2012 11:38 AM
Subject: LF: Argo vs SpecLab

I have recently being playing with the settings in SpecLab, and have
managed to reduce the effect of some local QRM. However, I am still
plagued by DCF39 data bursts. When using Argo (1.3.7) these are
almost invisible, but SpecLab still displays them.

I have the SpecLab Limiter set very hard, and the Noise Blanker on,
and this helps, but it is still nowhere near as good as Argo in
taking out the data bursts.

Any ideas?

Mike, G3XDV
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