[RTTY] FSK Readouts vs AFSK

[k0bx at arrl.net]

Using AFSK you are usually off a bit from the FSK frequecy from the DX Spots, 
but it is allow to use you hand to move the dial up or down to find the 
station.  So this is no big deal.

I use a ICOM IC-756PROIII on rtty and use FSK.  Everythiing works fine.  
But when I do use AFSK, I set MMTTY for a mark tone of 1445 with 170 hz shift.  
The PRO3 when you hold the SSB button in LSB become LSB-D and the PRO3 centers 
the bandpass to 1500 HZ.  This way the incoming tones are able to pass through 
the filters down to 250 HZ.  Works that way on PSK too.

I hope to see everyone in the WPX RTTY this weekend.

Joe K0BX
 Stop the insanity!
Please do not add me to any distribution lists (Joke, Stories or Junk) without 
my permission. 





________________________________
From: Al Kozakiewicz <akozak at hourglass.com>
To: Bill <bmarx at bellsouth.net>; RTTY reflector <rtty at contesting.com>
Sent: Mon, February 6, 2012 9:21:52 PM
Subject: Re: [RTTY] FSK Readouts vs AFSK

I'm not 100% sure I'm following the point, but if the point is that you can 
decide to decode something other than 2125/2295 when running AFSK in order to 
make the math for the conversion to the "FSK frequency" simple to do in your 
head, why not?  When I was first trying RTTY and running AFSK I never ran the 
standard part because 2295 Hz was usually just outside my SSB filter passband.

If you're using AFSK, you will probably eventually want to use a narrow SSB 
filter whose upper limit will end up being lower than 2kHz anyway, forcing you 
to change to a different tone pair.  From a technical standpoint, it doesn;t 
much matter at all what tone pair you choose as long as the separation is 170 
Hz.

Al
AB2ZY

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