[pskmail] Re: packet loss due to the automatic squelch control

  • From: Pär Crusefalk <per@xxxxxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Sat, 11 Feb 2012 19:12:36 +0100

Hi Peter,

Just wanted to tell you that I am working on this issue now. At the moment we just send the text as is, that works great for plain english (ascii) but all other characters will look bad. So I need to MIME encode the text. I'll need to test somewhat before I can release it but I will.

73 de Per, sm0rwo


Peter Olsen skrev 2012-02-04 19:22:
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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