-- Bill Turner <wrt@dslextreme.com> wrote:
_________________________________________________________
When AFSK is done properly, it is indistinguishable from FSK at the
receiver end. The problem is it can easily get out of adjustment,
mainly by overdriving the audio stages in the transmitter. When this
happens, the transmitter often outputs the signal at two or more
frequencies. I often see this during contests.
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I 100% agree with Bill's comment about overdriving the audio stages with AFSK.
While I was playing around in WPX RTTY several times on 10 meters my "clear run
frequency" was destroyed by what I thought was someone moving in a 100 Hz or so
away from me. Instead each time when I checked it was the same LU who was
CQing about 2 KHz away from my frequency with a signal that had to be over
driven as even with my AGC off kicking in the 250 and 330 Hz filters didn't do
any good. If nothing else, it is a sneaky method to insure everyone else gives
you a clear frequency;-)
73 W0ETC
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