[Elecraft] KX3 - AFSK RTTY

[Don Wilhelm]

Keith,

The other station will not know what mark frequency you are using.  The 
only thing the other station hears is your mark and space frequencies 
(and the resultant shift), so if you are using the proper RTTY shift, he 
should copy you with no difficulty.

Yes, there are some folks who are reluctant to use low tones with RTTY 
because the 2nd harmonic of that tone falls within the SSB bandwidth.  I 
would suggest you ignore those comments - the KX3 works fine with the 
lower tones.

I am not certain what you meant about FSK D - you should be using AFSK 
A, so FSK D is not relevant.  I do not do Mac and I do not do CocoModem, 
so this may be some mixture of settings between the KX3 and CocoModem 
that do not make sense to me.
Does CocoModem support soundcard RTTY?  That is what you should be 
using, no matter what CocoModem calls it.

FSK D mode with the KX3 is used to send RTTY from CW paddles (not 
computer input - the KX3 must see the dots and dashes directly from the 
paddles).  An alternative to the paddles for FSK D input is a software 
application that can send "KY" commands with ASCII text.  Few 
applications other than KX3 Utility have that capability.

73,
Don W3FPR

On 3/28/2017 8:04 PM, Keith Onishi wrote:
> I have been trying to set up for RTTY operation with KX3 + iMic + cocoaModem on Macbook Pro, but not successful.
> Mode selection on KX3 is AFSK A and cocoaModem setup is matched to the KX3 setting.
> RTTY signal received by KX3 appears not around 2125Hz but around 900Hz. So, I set cocoaModem’s mark frequency to 915Hz. With that setting, decoded text appears on the screen. KX3 VFO is properly tuned to the signal, of course.
> When FSK D on KX3, all is same. RTTY signal appears around 900Hz as well.
>
> I found this had been discussed several years ago in the ML, but no change in KX3 specification since then.
> I would like to know if this mark frequency is OK in QSO with other RTTY station.
>