[pskmail] Re: packet loss due to the automatic squelch control
- From: "Rein Couperus" <rein@xxxxxxxxxxxx>
- To: pskmail@xxxxxxxxxxxxx
- Date: Mon, 6 Feb 2012 10:14:01 +0100 (CET)
Peter,
the squelch does not work on signal amplitude, but on signal decode quality.
The upper limit of the auto squelch has been set to 30%, and normally
a signal should have at least 30% to be of any use in pskmail arq.
We can provide a possibility to switch it off anyway in a later release...
One possibility is to look for a marker file on startup of the program.
Rein EA/PA0R/M
>Dear developers,
>
>I am using jpskmail 1.5.x with fldigi V3.21.8
>
>I have noted that from some version 1.+ of jpskmail there is an automatic
>squelch level adjustment. I have also read about it in the manual.
>
>Is there any way to turn it off, so a manual setting can remain in effect?
>
>With the conditions at the home QTH, the automatic adjustment often
>results in a too high level, causing my fldigi to loose packets during QSB
>or signals from relatively weaker stations.
>
>It seems to be caused by two things:
>
>1) Level is adjusted (somewhat) upwards on pulse noise
>
>2) Level is adjusted upwards also during reception of a real signal
>exceeding the current squelch level.
>
>
>I think in general it is very difficult to design an automatic squelch
>level function which will be adequate for all circumstances, so I would
>like to propose some setting for turning it off and on. Otherwise the
>algorithm should be improved to not adjust upwards during the presence of
>a carrier and to be less reactive to pulse noise.
>
>The condition "presence of a carrier" could be simplified to "a pskmail
>packet being received", i.e. when the client sees the packet header, it
>could stop adjusting the squelch, until the packet <eot> is detected, or
>when the packet is deemed terminated on a timeout. In this case the
>squelch would still adjust upwards on non-pskmail signals, but that is
>probably a minor imperfection.
>
>
>Regards & 73
>
>Peter, OZ1QT
>
>
>
>
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