[RTTY] MMTTY, permanently disable AFC

[Tim Shoppa]

Joe writes:
> This limits AFC so it will move *no more than 70 Hz* (.4 x 170). That
> will allow AFC to "fine tune" but not cause you to go chasing all over
> the band. Thanks to G3YYD for the idea <G>.

Thanks Joe, I think you hit exactly on my objection to MMTTY AFC. It
somehow gets turned on, then next thing I know, MMTTY's center frequency
has wandered way out of the passband and signals that sound fine to my ears
are not producing the crosshairs in the X-Y and I'm wondering if I had a
wire broke or Windows locked up or something.

2Tone AFC seems much more reasonable, it's like it has a rubber band that
drags AFC back to nominal center frequency rather than letting it wander
off into hyperspace with no return.

All that said I am still more comfortable with using RIT to decode
off-frequency callers when I'm running, than relying on AFC.

I'm not ready to give up on MMTTY :-). I find it often decodes better than
2Tone in contest conditions and am most comfortable when I have both MMTTY
and 2Tone decoding.

Tim N3QE