13032Re: [wsjtgroup] JT9 use on 6 meters
- Jul 30, 2014Hi Jay,
> I tried using JT9 on 6 meters today with not much luck. I wasIt's hardly accidental that the docs explain that JT9 was designed for
> seeing J69DS trace easily on the waterfall but just a couple
> of decodes. The problem appears to be a slight receiver drift
> in my Yaesu FT2000. I was wondering if it is possible to
> introduce an AFC button for JT9 operation that would lock
> on to the trace that you are trying to receive and compensate
> for any radio drift? I am using WSJT-X ver. 1.3, r3673. If
> there is a more recent version, I would like a link to it.
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.
Much better to use JT65A on 6 meters; the extra-narrow bandwidth of JT9
is hardly needed on 6, anyway.
-- 73, Joe, K1JT
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