[RTTY] MMTTY/PRO III Observations on FT5XO signal

[Don Hill AA5AU]

During the FT5XO operation, I was able to look at different settings in MMTTY
and in the Icom IC-756PROIII to determine what worked best on weak signals.
After all, they were pretty weak on all modes here and only heard them on 17,
20, 30 and 40 meters.  Their best signal was on 30 meters.

I made some discoveries which surprised me and may be of some interest to
others.

As many of you know because I reported earlier, the Twin Peak Filter (TPF) works
really great in the PRO III (probably same as PRO and PRO II) when the RF gain
is backed off.  I used this in both the XE and BARTG RTTY contests with improved
copy on weak RTTY signals.

During the FT5XO operation, I found several opportunities to use a variety of
settings in the PRO III to copy them on the different modes.  I had never done
this before, but at one time I switched in both pre-amplifiers and backed the RF
gain off on RTTY, CW and SSB to find that copy was increased dramatically.  With
both pre-amps enabled in the PRO III, it was the only way I ever heard them on
SSB.  I had a short 10 minute window at around 0430Z on night and worked them
short path.  On CW, they were S9 with the pre-amps on.  The secret was to back
off the RF gain.  So I kept it that way for the rest of their operation.

When I used the pre-amps on RTTY, I was the only station in New Orleans (in the
DDXA anyway) that was able to print them consistently on 30 and 40 meter RTTY.
I sat on 2 meters and called out callsign after callsign of stations they were
working in an effort to help others get through and everyone, including me, was
amazed that I was copying them as well as I was when others were only getting
bits and pieces.

This brings me to another point and that is the setting of MMTTY I was using.  I
was using the #3 profile that comes default with MMTTY and that is Fluttered
Signals (FIR).  During the several hours that I spent watching them on RTTY, I
was able to change the profiles back and forth enough to determine that FIR
worked the best and by a LOT on their weak, sometimes fluttery signal on 20, 30
and 40 meters.  It wasn't so much that their signals were fluttered, except on
20 meter long path, but the QSB was very heavy all the time.  I was only able to
copy them a few minutes on 17 meter RTTY long path one day before they went QRT
(I did not work them on 17 meters at all).

Although I have to admit that having rotatable dipoles on 30 and 40 meters
helped a great deal, I still believe that the PRO III twin peak filter, combined
with the pre-amplifiers (and backing down the RF gain) was the key to being able
to hear them better than others in the local area.

The biggest thrill of the whole operation was being able to watch my good friend
Don, W5FKX, work them on 30 meter RTTY.  He, along with big guns like W5ZPA and
K5KR had been calling for over 2 hours.  Finally Mike W5ZPA made a contact at
10125 KHz (FT5XO was at 10120.000 on my dial).  Don jumped on that frequency and
made the next contact.  I then worked them followed by K5KR and another local
W5KB.  It was a new one on RTTY for W5FKX and an all time new one on any mode
for W5KB and that gave me a special feeling to watch them make the contacts.

It was really cool to work them on 40 meter RTTY before the crowd got there.
After all it was #303 on 40 meters for me (#154 40M RTTY).

73, Don AA5AU