[GreenKeys] RATTS

[Jerry]

In a word, no..only the shadow would know...

Jer -n6jp-

----- Original Message ----- 
From: "Eugene Hertz" <ehertz at tcaf.org>
To: <greenkeys at mailman.qth.net>
Sent: Friday, February 25, 2005 2:18 PM
Subject: Re: [GreenKeys] RATTS


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?

Thanks

>
>Low band fsk rtty is neither usb or lsb. It is two frequencies, one for 
>the
>mark and one for the space tone. Ham rtty is usually sent so the space 
>tone
>is lower than the mark tone. The comercial rtty was so the space was 
>the
>higher tone. When using audio demodulators and the switch (if it has 
>one)
>set for normal then you receive in the lsb mode for hams on all bands 
>and
>usb for the comercial. YOu can use either sideband if you switch the 
>audio
>tones to the "reverse" position.
>Even the 2125 and 2295 tones do not mater. Without getting in the the 
>very
>technical reasons, any tone pair 170hz apart can be used and the person 
>on
>the other end will never know the differance.
>
>de KU4PT
>
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