[GreenKeys] rtty reception woes

Gary Chatters [email protected]
Tue, 6 May 2003 12:06:56 -0400 (EDT)


On Tue, 6 May 2003, gil smith wrote:

>
>  freq     signal  shift   baud     text
> 7.58121    fair    170    45.45?   garbled
> 7.59515    good    850    75?      garbled
> 7.45614    fair    850    75?      garbled
> 6.45163    good    850    75?      garbled
>

I don't know much about RTTY outside the hambands.  Try listening on the
20m or 80m or 40m bands.  Most RTTY signals there are likely to be 170Hz
shift, 45.45 baud, 5-bit Baudot code.  Also, try listening to the ARRL
RTTY bulletins.

> I also found a 170-Hz signal (forget where) that was not keyed constantly;
> in fact it was keyed at a periodic rate of about a second on, three seconds
> off.  Does that make any sense?
>

This sounds like SITOR or AMTOR (ham version of SITOR).  Messages are sent
in a burst of a few characters, then the receiving end sends an
acknowledgement and the sender continues with the next group.  You may
hear a weaker signal in the three second off period.  Or maybe it was in a
broadcast mode and not receiving ACKs.


Gary