[SFDXA] Are You Frequency Confused with RTTY?

[Kai Siwiak]

Hi Bill
The main distinguishing feature of that article is that it is wrong 
because it assumes a specific set of tone frequency offsets from the 
dial frequency.

For example:
To operate ham-RTTY (170 Hz shift, 45.45 baud) in the 60 m band channels 
the proper radio setting is upper SSB, radio dial set to the upper SSB 
dial frequency for that channel, and RTTY operated in "AFSK" mode. You 
would then select the two tone offsets as 1415 Hz and 1585 Hz.  Thus, 
fulfilling  the FCC/NTIA requirements that:
(1) you must monitor the channel for upper SSB voice transmissions, and
(2) the data signal must be centered in the 60m band channel.

You can do this using the popular MMTTY software by editing the 
Mmtty.ini file so that the line "Mark= ..." includes 1415 Hz.
Then in the main panel choose MARK=1415, and "Rev".  The radio must be 
in upper SSB.
Since "Rev" is selected the MARK frequency is actually 1415+170 = 1585, 
while the SPACE frequency is actually 1415 with respect to the upper SSB 
radio dial frequency.
[Note: that is a nomenclature problem in MMTTY when the radio is set to 
upper SSB]
On the air, the two tones will be 1500 +/-85 Hz. above the published 60m 
band channel, or as required by the FCC and NTIA, dead center in the 
channel. Said another way, if you monitor the band with a spectrum 
analyzer you will find the two RTTY tone +/-85 Hz from the channel 
dead-center frequency - just what the FCC/NTIA want.

You can operate RTTY this exact same way ("AFSK", upper SSB, "mark=1415" 
in MMTTY (Mark will actually be 1585), and "rev") on any ham band where 
data is permitted. Then your RTTY "spotting" frequency will be your 
upper SSB dial frequency plus 1585. That is the frequency that hams 
traditionally "spot". 

Yes, its that easy to do RTTY, and to "know your RTTY frequency", and to 
set up for operation on the 60m band channels

73
Kai, KE4PT


Bill wrote:
> Frequency Readouts For RTTY...
>
> http://www.eham.net/articles/27625
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