[TenTec] MMRTTY+ Omni 6 question

Jim Brown k9yc at audiosystemsgroup.com
Tue Feb 4 18:38:31 EST 2014


On 2/4/2014 12:28 PM, Carter wrote:

> >I use MMTTY with AFSK
> > and VOX, feeding the sound card to the line input of my radio (a K3).
> > In AFSK mode, we can turn AFC and NET on and off independently.
>
> > Most serious RTTY operators who use AFSK turn AFC and RIT off when
> > calling a station, and use RIT or AFC when calling CQ.
>
> Call me old-fashioned, but I much prefer to use true FSK rather than 
> AFSK to avoid the dreaded and accidental condition of overdrive. 

Obviously, one must be careful about setting levels, but that's fairly 
easy if you know what you are doing.   Another reason for using FSK with 
SOME radios (don't know if this applies to the Omni 6) is that they must 
use FSK to be able to center the RX passband at the desired RTTY decode 
frequency to get IF filters to work. That is true of some ICOM radios, 
for example.

> Also, after being spoiled by years of true simplex with Ka-Gold and 
> Writelog, using RIT would seem like a step backwards for me.

The reason for AFC or RIT is that some stations call off frequency, so 
if we want to decode them, we must use one or the other to center the 
decoder on them.

73, Jim K9YC


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