[Elecraft] MMTTY FSK

[Mike Cox]

The only real difference I've heard is that on some strong signals you 
can occasionally hear the unwanted sideband mirroring the intended AFSK 
signal. This signal is at a level reduced by the unwanted sideband 
suppression characteristics of the transmitter involved and separated by 
twice the modulating tone frequencies. This might put the two signals 
over 4 KHz apart, making it not apparent who the culprit is. It's pretty 
easy to see the problem with a panadapter. Note that some current radios 
(for example. IC756ProIII) only rate their transmitted unwanted sideband 
suppression at -40 dB (K3 is -50 dB). Some older radios are much worse. 
An unwanted sideband of -40 dB from a 1.5Kw signal would be 150 mW. I've 
worked DX with less.

On 6/13/2010 17:07 PM, N1JM wrote:
> In  real world operating, has anyone really experienced a difference or could
> tell a difference?
>