This past weekend in WPX, I ran 4 MMTTY windows in WriteLog (SO1R), each
with a different profile (Standard RTTY, Flutter, Flutter (FIR) and
Multi-Path). As I had hoped, it worked great. There were a number of times
when only one of the 4 windows copied clearly. And, there were a few times
when none of the windows copied 100%, but by visually combining two or more
of them, a high confidence copy could be created. The latter case is when a
call sign or serial number is repeated in a transmission and one window
copies the first instance of the "word" while another window copies a
subsequent instance of the "word".
Two implementation details make this an easy and practical thing to do.
First, Windows XP allows multiple applications, or multiple instances of the
MMTTY application in this case, to be driven from a single sound card. So
far as I can tell, the previous Windows operating systems do not allow this.
Second, WriteLog 10.45M has a new feature in the Rttyrite File menu, called
'Clone (read only)'. After opening up the first Rttyrite window and setting
it up to work with MMTTY, additional Rttyrite windows can be "cloned" or
opened up. Of course, each one has its own RTTY Control Panel window, but
after I set the profile (and turned off AFC, which is defaulted ON when you
select a profile), I then minimized the RTTY Control Panel out of view. I
arranged the four Rttyrite windows in a 2x2 pattern that fits nicely on the
screen with all the other WriteLog windows. Note that only the first
Rttyrite/MMTTY window is set up to transmit ... the other three are
read-only windows.
73,
Ed - W0YK
P.S. I have a funny anecdote about my effort to set this up last week.
Since I was adding 3 more windows to my screen, I decided to swap in a
slightly larger CRT on one of the shack computers. As I was connecting
everything up, I found that the CRT video cable had a second cable
integrated into it that was a small cable with 1/8" phone plug. Turns out
it comes from a small microphone buried in the CRT Bezel and plugs into the
microphone input of the sound card. COOL!, I'm thinking ... but not really
thinking clearly enough. I don't know what I thought I'd ever use that
microphone for, but what the heck, I plugged it in anyway.
Well, at this point in the story, most of you can see the impending disaster
about to unfold during the contest. However, my feeble brain didn't "get
it" until Saturday night after I had struggled through some 700 QSOs. I was
having a horrible time getting clear copy, even on strong crisp signals.
Nothing but gibberish a lot of the time. So, I was constantly asking for
repeats and just having to give up on some of them. Eventually, one of my
four Rttyrite/MMTTY windows would copy enough for me to complete the QSO.
So, at that point, at least I was pleased that the different profiles were
paying off.
What I finally discovered late Saturday was that the speaker audio from the
rig was being picked up by the CRT microphone and fed into the sound card,
mixing with the direct signal from the radio. This created some
approximation of a fluttery, multi-path signal that MMTTY had a lot of
trouble trying to decode. Unplugging the microphone cable returned the
decoders to near-perfect copy and then they all operated as described above.
So, if you ever want to sabotage a "friend's" (or, your own) RTTY setup, you
now have another alternative to consider!
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