Lest anyone doubt the problems with AFSK and users who follow the
"all knobs to the right" doctrine take a look at the spectrum of
one lid on WSJT : http://www.w4tv.com/HI8XXX.jpg.
The user is running a tone frequency around 380 Hz and so badly over
driving the mic preamp in his rig that one can see at least *seven*
harmonics of the fundamental stretching to over 3 KHz where the TX
filter finally rolls off - a later observation showed harmonics out
to the *ninth* at over 3500 Hz. This idiot destroyed a very good six
meter opening for most of the eastern half of the US as he was the
only signal anyone could copy in those minutes he transmitted - the
only stations worked anyone were those who worked him.
Any doubt about the destructive power of AFSK in the hands of a lid?
FSK on some transmitters may be a bit "wide" but it's not going to
ruin an entire band.
73,
... Joe, W4TV
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