[RTTY] RTTY spectrum analysis article

[Jim W7RY]

I disagree Jeff. If an S2 signal you are trying to receive is 300 or 400 Hz 
away from a S9+20 signal, the radios AGC will not allow you to receive the 
week signal. Filters in the radio are essential!

73
Jim W7RY


-----Original Message----- 
From: Jeff Blaine
Sent: Thursday, January 10, 2013 6:34 AM
To: Al Kozakiewicz ; RTTY Mailing List
Subject: Re: [RTTY] RTTY spectrum analysis article

The best place for RTTY rx filtering is in the demod, not the rig.  narrow
crystal filter and it's group delay gives more problems than it solves.

The solution is to run a filter wide enough to let you quickly tune (400-500
hz?), but not so razor sharp that the rig rather than the demod is doing the
selectivity filtering.

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-----Original Message----- 
From: Al Kozakiewicz
Sent: Thursday, January 10, 2013 8:30 AM
To: RTTY Mailing List
Subject: Re: [RTTY] RTTY spectrum analysis article

>No, this doesn't necessarily mean you should give
>up "true" FSK keying. There are things you can do about it, and some
>people are people taking responsibility and doing these things--please read 
>the
>article!

That was depressing.  Transmit filters are only enabled on the Icom radios I
have on SSB, so there is no apparent option for improvement that I can see
for without switching to AFSK which, in turn, makes the radios just about
useless for contesting as there is no practical way to use the RTTY Rx
filters without also transmitting FSK.

Unless I missed it in the article, I see no way to improve things short of
buying a new radio with a design that does not currently exist!

Al
AB2ZY
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