Andy,
I did a test last week with JT2 on 500kHz and unfortunately no one was
able to decode it - not sure what the problem was. I wonder if you have
successfully used JT2? I loaded messages into the TX1 through TX6 boxes and
pressed the corresponding button to the right of the box - noises came out the
sound card and were sent out on 500kHz but no decodes despite multiple
listeners. If you could advise how to properly Tx that would be appreciated!
The program looks very interesting but the documentation is sparse at best.
--
73 Warren K2ORS
WD2XGJ 136-140kHz
WD2XSH/23 505-510kHz
WE2XEB/2 160-189kHz
WE2XGR/1 505-515kHz
FN42hi
http://www.w4dex.com/wd2xgj.htm
-------------- Original message ----------------------
From: "Andy Talbot" <[email protected]>
> I've been watching with interest the use of the narrow versions of the
> various data modes being used on the 500kHz band, and anyone who reads
> RadCom will see the mention I made in the Data Column last month of
> the parallel FSK and PSK31 trials..
>
> Joe Taylor, K1JT has written a suite of programmes using
> multi-frequency FSK coupled with heavy source coding and forward error
> correction for extreme weak signal communications on VHF through to
> Microwaves, especially targetted at Tropo, EME and Meteor scatter.
> I mention it on this reflector as he has now introduced two new
> embryonic modes (JT2 and JT4) that include narrow shift options (a few
> tens of Hz overall) that may be well-suited to MF communications.
>
> I suggest a visit to his web site to read up on the modes and
> techniques he employs, and download the latest version of WSJT. The
> main web page doesn't mention JT2 / JT4, but the beta version at 5.9.8
> is detailed in the links shown here, and experimenters are invited to
> download an try it out. There is quite a lot of description and
> theory supplied, and makes for a fascinating read!
> The heavy error correction and redundancy adds considerably to the
> weak signal capability.
>
> Main WSJT site http://physics.princeton.edu/pulsar/K1JT/
> JT2/4 description http://physics.princeton.edu/pulsar/K1JT/JT2_JT4.TXT
> Download latest WSJT software
> http://physics.princeton.edu/pulsar/K1JT/WSJT598.EXE
>
> I implemented direct DDS-generated JT65B on the GB3VHF 2m beacon a
> couple of years ago, and the mode is now being used on the GB3RAL
> 40/50/60/70.05MHz beacon family. Details of GB3VHF can be found on my
> web page shown below. Reception reports all agree on the mode's
> extreme weak signal capability and a major improvenment over CW alone.
> It will be interesting to see if the narrow band versions have
> anything to offer the lower end of the spectrum.
>
> Be aware though, the JT modes do rely on quite accurate timing, and PC
> clocks need to be set to within a second or two of each other.
>
> Andy G4JNT
> www.scrbg.org/g4jnt
>
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