[pskmail] packet loss due to the automatic squelch control
- From: "Peter Olsen" <petero@xxxxxxxxxxxx>
- To: pskmail@xxxxxxxxxxxxx
- Date: Sat, 4 Feb 2012 19:22:04 +0100
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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