[RTTY] Multiple MMTTY Windows

[Don Hill AA5AU]

Hi Ed,

I have replied to the reflector because I thought it would be of interest to
others.

Great work on the MMTTY testing in the cloned Rttyrite windows.

I did want to add something.  I did not try the multiple MMTTY windows on my XP
machine this weekend, but I did pay closer attention to the times the DXP-38
out-copied MMTTY.

I found two instances where the DXP-38 consistently out-copied MMTTY.  When a
station answers my CQ and is mostly out of my 250 hz IF passband filter in the
radio, the DXP-38 still copies but MMTTY doesn't copy at all.  I don't know why
this is, but there were times when the signals was so far out that I could
barely hear any tones at all, but the DXP-38 still copied.  If I have my 500 hz
on instead of 250 hz, then MMTTY doesn't have a problem, but I rarely use 500 hz
in contesting.

The other times when the DXP-38 is better is when in the S&P mode and tuning
upon a signal.  While moving the VFO to center the signal, the DXP-38 starts
copying way earlier than MMTTY.  It seems MMTTY must "lock" onto the signal
first and can't do it if I'm tuning the VFO fairly fast.  Since I tune very fast
trying to get to the next signal as quickly as I can as I'm moving up or down
the band, the DXP-38 really outshines MMTTY.  This is a great timesaver as well.
If the station I'm tuning onto is sending his callsign as I'm tuning onto him, I
get his call in the DXP-38 window and don't have to wait for the station to
transmit again to get the call.

73, Don AA5AU



-----Original Message-----
From: rtty-bounces at contesting.com [mailto:rtty-bounces at contesting.com] On Behalf
Of J. Edward (Ed) Muns
Sent: Monday, February 16, 2004 2:33 PM
To: rtty at contesting.com
Subject: [RTTY] Multiple MMTTY Windows

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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