[Elecraft] KX3 + JT9 -- any successes?

[Jim Brown]

On 7/30/2014 8:58 AM, Martin AA6E wrote:
> --After doing the procedure, I can work JT65 pretty reliably for P ~ < 
> 3 W.
> --I can decode JT9 sometimes, but I can't get anyone to decode my 
> transmissions.  (20M)
>
> The result of the temperature calibration was that I seemed to have ± 
> 1 Hz stability (compensation?) at 50 MHz from 22 to 55 C. I thought 
> that was pretty good, but it still does not seem to give good JT9 
> results.  (JT9 is extremely narrow-band with 9 tones spaced at 1.7 Hz 
> across ~15 Hz of bandwidth.) 

I've successfully made a few JT9  QSOs on 6M with my K3, and get good 
copy on other JT9 signals that I know are coming from K3s. But K1JT 
advises against using JT9 on VHF (and urges caution even about 10M) 
because of its sensitivity to frequency drift. Quoting from his post 
today on the WSJT reflector,

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"It's hardly accidental that the docs explain that JT9 was designed for
the LF, MF, and HF bands.  Even 10 m is s stretch, with some radios and
some propagation conditions.

"Like JT65, the JT9 decoder does have an AFC as part of its bag of
tricks.  It's always engaged, solving for a linear frequency drift term
before decoding is attempted.  The algorithm can perhaps be improved.
It's a tougher job with JT9 than with JT65 -- not least, because the JT9
protocol devotes only about half as much time to a synchronizing tone,
compared with JT65."

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73, Jim K9YC