[Elecraft] Sidetone Pin Pricks / DSP / QSK

[Henry Gardiner]

>
>From: "Indy" <kt5x@spinn.net>
>To: <elecraft@mailman.qth.net>
>Date: Fri, 2 Apr 2004 06:39:45 -0700
>Subject: [Elecraft] sidetone pin-pricks
>
>I have "pin-pricks" in my sidetone when the QSK changes over.  this =
>began with the change from the KAF2 to the DSP.  Lyle has a mod he =
>suggests which slows the rate of the QSK way down.  Wayne suggests this:
>
> >"Another way to achieve the same effect is to insert a largish
> > resistor (try 100 k) in series with pin 17 on the MCU. This would add
> > only 150 microseconds to the /mute fall and rise times."
>
>Has anyone tried Wayne's suggestion?  I am not anxious to cut a trace =
>without knowing if it works!

   I have installed the 100K resistor in series with pin 17 of the MCU.  It 
has largely or entirely cured the problem of audio QSK transients said to 
be affiliated with the installation of the DSP option that I have.  I run 
at 15 wpm and can still hear between dits quite adequately.
   The DSP option has been a success.  I have it set up per the manual 
except for the narrowest filter being 50 Hz wide.  It's a big help to have 
one of the spectrum programs to confirm that the DSP and the crystal 
filters agree as to what the center frequency is.  It's also good for 
admiring the passband shape of the DSP.  The xtal filter alignment process 
is sensitive to frequency drift in the BFO so I adjusted those filters with 
the cover on and a long warm-up period.
   I gave up on using the clock, not that I really need it.  Mistiming of 
the button pushes causes a DSP parameter to change.
   The receiver's performance has been exceptional.

Henry AC5LA