[RTTY] TX and RX not on same frequency

[Bob Darlington]

Hi guys,

I'm new to RTTY when it comes to using an FSK interface.  AFSK, easy peasy
and I've done it off and on for years.

I recently purchased a W3YY interface board, soldered it up, got it mounted
in a box and then cabled to my rig.

I'm running an Elecraft K3S radio using MMTTY software (either by itself or
through N1MM+).

In addition to this I'm running Win4k3Suite for the panadapter display.

What I see is that I can decode rtty just fine.  If I try to respond to a
CQ my transmitted signal is next off by a bit.  I can see it on the
panadapter that I'm not in the same column, so to say, but instead off by
several tens of Hz or more.

This gap seems to depend on the filter setting in the rig.   I'm using FSK
D (data) mode for all these tests.   I just can't seem to get it to work
right.   I randomly found a webpage that said to push the "HAM" button to
get the tx and rx to align.  I don't know why these would drift apart, but
I bit and saw no improvement.  It did snap the mark frequency back to 2125.
   I figured I should turn off AFC.  I still have this problem, but the
mark frequency doesn't drift around as the software tries to figure out the
rtty signal frequency.

What am I doing wrong?   I feel like the little waterfall display and band
scope in MMTTY is just off by a bit and don't know how to correct this.
It's listening to the wrong frequency I think, but am unsure how a filter
change on the rig would change this.  I'm not attempting to use the double
peak rtty filter, although when I have tried, it doesn't seem to make any
difference.


All that said, I also see that I am MUCH faster at pouncing on signals
using fldigi with AFSK signalling so may participate in the RTTY Roundup
that way.

Thanks for any suggestions,
Bob - N3XKB