[GreenKeys] RATTS

[WA5CAB at cs.com]

The short answer is Yes.  Turning on the BFO produces a heterodyne (two 
actually, but only one is in the audio region) which would then be fed to an audio 
type (not the only type, BTW) of receiving converter.  

The most important thing that a mode switch does when you switch it to CW, 
SSB, ISB, LSB or USB (depending upon how the receiver is built and how the mode 
switch is marked) is to turn on the BFO.

The short answer to your second question is No.  There would be no way to 
tell the difference.

The longer answer would add the weasle statement "assuming that the 
suppressed carrier was not strong enough to be detected by person C.  The spectrum 
analyzer (panadaptor) displays would be the same in either case.


In a message dated 2/25/2005 4:18:46 PM Central Standard Time, 
ehertz at tcaf.org writes: 
> Can one or can one not use "CW" mode in a receiver and apply a BFO against 
> the shifting carrier? Shouldnt this work too? That to me (very very novice 
> understanding of stuff) would really explain whats going on, making discussion 
> of USB and LSB moot, no?
> 
> Here's a questions I have had for some time and now have the nerve to ask...
> 
> If someone were to use a spectrum analyzer to look at a "rtty" signal coming 
> in off the air, would they be able to tell if the signal was generated 
> through ASFK or FSK? In other words, if person A were to apply an audio shifted 
> signal to a transmitter in (say) LSB mode, and another person "B" keyed an fsk 
> mode in a transmitter, do the signals they produce differ in any way? Could 
> person C tell which sender is using which mode?
> 

Robert Downs - Houston
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