[GreenKeys] Might be a bad weekend...

[Howard Weeks]

Some years back, the DCS HF networks sometime run up to 24 channels 
of FSK TTY on one of the audio slots.  If my memory is not failing me 
(and it may) each of these rtty slots used 85 cycle shift.  I 
remember some that were set up for 100 cycle shift.  All of it fit 
into one audio channel on the system which had to have pretty linear 
response to keep down distortion from intermod products.  

Receivers were R-390s with some special sideband demodulators 
followed by the multichannel TTY demodulators.  On the air, these 
things sounded like a 4 engine piston airplane with the engines 
slightly out of sync.  
 
Howard Weeks
Harlem, GA 
K5JCP