[RTTY] K3

Kok Chen chen at mac.com
Tue Jan 6 18:27:16 EST 2009


On Jan 6, 2009, at 2:29 PM, Jim W7RY wrote:

> FSK is only one tone at a time. A 2-tone test would not be a valid  
> for FSK
> or AFSK bandwidth.

Except that I use waveshaped AFSK to reduce the FSK keying sidebands.   
Hence two tone IMD matters because the tones do "overlap," albeit at  
low levels.

Only way out is to use a frequency slew (the slewing modulation being  
a Blackman window, for example) to get around the problem.  But PSK31  
will still be a dilemma for me.

73
Chen, W7AY



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