[RTTY] Contesting w/ 2 Tone & MMTTY

Ed Muns ed at w0yk.com
Mon Apr 8 20:48:20 EDT 2013


Jerry W6IHG wrote:
> And those of us with the nice Flex radios are stuck in AFSK. 
> Since there is an interface to control NET (used by N1MM), 
> perhaps Writelog's Xmmt.ocx can exploit that. Although I have 
> never used it, does the "This is the Run Station" on the 
> Radio menu inform Writelog of what the operator intends to do?

Specifying a radio as "Run" in WriteLog is just a label, not tied to how the
radio is really being used.  In other words, you can name a radio "Run" and
still search & pounce with it.  So, that won't work as a trigger to turn off
Net.

Based on seeing successive QSOs on the same frequency WriteLog does declare
a radio is running and put an 'R' by its entry in the Network window, but
again this is a little loose and probably not satisfactory for controlling
Net.

Without major change to WriteLog to add the sense of state (Run vs. S&P),
the best option is to add a command or button.  The command could be
optionally added to CQ messages by the user, but then there would need to be
a way to turn Net back on for S&P, perhaps a button.

> Joe, tell me more about the "RXM_Switch command"

I believe this is a command in the XMMT interface that can be used to
control Net.

> It seems that 60 Hz off frequency when I am running in AFSK 
> puts me into the guy next to me. Not nice./rtty

I agree.  However, if you are in the habit of always using RIT to zero-beat
the station you choose to work, then AFC/Net are effectively defeated.  And,
since the "AFC" in 2Tone is only +/- 60 Hz, this is really not a big deal.
I have always used RIT so 2Tone's "AFC", and therefore Net, is a don't care
in my operating.

It should be noted that 2Tone's very narrow AFC range is simply for the
purpose of achieving perfect zero-beat so that its decoding algorithms are
optimum.  This is very different than MMTTY's AFC that pulls in stations
from much further away and gives the operator no easy way to zero-beat.  The
two pair of reference lines in 2Tone are excellent for quickly zero-beating,
even better than the MMTTY display options for zero-beating.

Just using 2Tone dramatically demonstrates how "non-AFC-like" its AFC really
is.  You can see the tones of an off-frequency caller in the passband but no
AFC locking takes place until you RIT the station into the +/- 60 Hz capture
window.    Once you've moved the RIT that much, it is trivial to continue
the last few Hz and get perfect zero-beat.

So, the bottom line for me is that neither AFC nor Net are much of a problem
with 2Tone.  In theory, yes, but in (the right) practice, no.

Ed W0YK



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