[RTTY] DESREVER

[Kok Chen]

On Oct 15, 2004, at 5:12 PM, James wrote:
>     Reversed Signal.  I am confused.  My RTTY Elmer some 34 years ago
> Said that the "standard" was LSB on all bands.

The only Amateur standard I know of is the one that states that the 
Mark tone of the frequency shift keyed signal needs to be the higher 
one on the RF spectrum.  And that the shift is kept at 170 Hz.  LSB has 
nothing directly to do with the standard.

It just happens that if you pick a 2125 cps audio Mark tone and 2295 
cps audio Space tone, that you would need to use lower sideband SSB to 
achieve the aforementioned standard.

You could just as well use 2295 Mark and 2125 Space and pick upper 
sideband SSB.  This is where the ability to transmit in reverse gives 
you the additional flexibility.  There is at least one rig I know where 
you have to use upper sideband on AFSK to use the narrow IF filters.

Alternatively, you can pick 1000 Hz Mark and 1170 Hz Space and LSB.  
The receiver at the other end won't be able to tell the difference 
between this and the two cases above.

73
Chen, W7AY