[RTTY] 200 hz filter on RTTY

[Charlesjr at afgimail.com]

There is actually three carriers on the signal you mentioned. The one in the middle is the 
strongest. The two weaker ones about 5hz each side from the middle one. I always thought it was a 
harmonic from some commercial station down in the 5.1mhz range. Sometimes you can see all 3 
sometimes not depending on condx's at the time and what your rig/software can hear.
I turned Autotune off in RITTY and had perfect copy with the weak right side carrier about 3hz away 
with the PROIII set at 350hz bw. The E4X sig was just a little stronger than the weak right side 
carrier with nothing showing on the s meter.
RITTY can also copy single tone rtty, even vy weak ones. Every time I see a spur I put the mark on 
it and invert the signal with perfect copy. I have been questioned before about spotting rare/semi 
rare dx. One even got on the air and called me a liar when I spotted the T6 when other W's could 
not hear him. Right after my spot EU jumped all over him and starting spotting him. RITTY pulls 
them out of the noise and in some cases you can't even see or hear the signal.
I did not log them on 30M. Maybe next time.
73
charles/kk5oq



------- Original Message -------
>From    : Don Hill AA5AU[mailto:aa5au at bellsouth.net]
Sent    : 5/31/2010 11:04:15 PM
To      : rtty at contesting.com
Cc      : 
Subject : RE: [RTTY] 200 hz filter on RTTY

 Test driving a new Icom IC-7600 on consignment from Icom.

Tonight there were several us in New Orleans trying to copy E4X on 10140 kHz.  There was a very 
strong steady signal right on his
mark frequency.  After a while, the carrier moved down about 40 hz.  At that time, I implemented 
the 200 hz filter on the '7600 and
the carrier completely disappeared from the passband and I was able to copy about 80-90%.

Something else the '7600 that the PRO III does not and that is the notch filter works on RTTY with 
the Twin Peak Filter turned on.
Didn't help with the signal when it was right on his mark frequency though.  Not much you can do 
about that although I have heard
rumors of a modem that could actually copy Baudot hearing only one of the two tones, but this could 
have been a HAL myth.

I think I remember someone, maybe Chen, saying a 200 Hz filter would not work on RTTY or something 
to that effect.  Maybe I don't
have the story just right, but it appears to be working great.  Too tight for contesting, but works 
when required.

73, Don AA5AU
 http://www.aa5au.com 
 http://www.rttycontesting.com  

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