[RTTY] RTTY Bandwidth and QRM

[Dennis]

Interesting conversation.

I went down to W100AW a couple of weeks ago, and operated RTTY
using a multi-channel decoder that I "designed" using MMTTY for DI1
and 2tone for the other 4 Rx channels.  I, too, thought that 1KHz would
be enough of a split, so I sent "up 1-4" with every transmission. Too often,
when I came back to a station, he did not come back to me.  I used
an EXCH message of "w1xxx 599 ct w1xxx", and would be greeted by
silence.  I would send the EXCH message a second time, and then the
station would come back, but for some it took a third time.  For the third
timers, they usually would send "QRM" when they sent me my report.
So, my conclusion, was that 1KHz for the split was not enough.  And
that was using W100AW, with 800w and a beam on 17m!

BTW, the multi-channel decoder worked great!  In the first hour I used
it, I almost made 100 Qs in the hour for one radio, and that was with lots
of stumbling on my part.  The 2nd and 3rd hour there did not go as well,
as the propagation gods didn't smile on me by closing 17m and higher.

I'm flying to Roatan, Honduras, HR9, on Thursday 5/22, and will be
there until Wednesday 5/28.  We will be entering the CW WPX contest
over the weekend, but after the contest I will be attempting to run RTTY
using the same multi-channel decoding scheme.  Because my signal will be
much weaker than the W100AW signal, I figured I would have even more
problems with others covering my calls, so I've already plugged into the
design a 2-4KHz split.

It will be an interesting, fun time to try this.  I would never do this in a
contest, but my goal is to come up with a system that could do 120-150
per hour on RTTY for DXpeditions, with only one transceiver.

Dennis W1UE