[RTTY] FW: OO Advisory kk5oq

[Kok Chen]

On Oct 21, 2005, at 6:24 AM, Anderson, Charles, MSG, 255ACS, SCS,  
6820 wrote:

> There is normally 6 or 7 stations during a contest that I can copy  
> in two or
> three places, mainly on 20 meters for some reason and not the other  
> bands.

Those are usually bad AFSK signals.  I have been known to futilely  
answer CQs from a station, only to find him again, usually another  
2125 Hz down! :-)

If the station is loud and I need it for a mult, I often tune down  
the band to look to see if I can find them again.

Some of the worst ones even generates a reversed RTTY image in the  
opposite sideband.  Often, you will find a reversed image whose mark  
tone is exactly 2125 x 2 Hz up from the LSB mark tone - an indication  
that the spur is probably generated by the under-suppressed upper  
sideband of an LSB transmitter.

I don't even think that monitoring the ALC will for sure guarantee a  
clean signal, either.  The reason is that you can still clip any mic  
preamp that may be in between the audio AFSK signal and the  
microphone gain pot (if the mic input is what is used to feed the  
audio signal into the rig).

73
Chen, W7AY