Rik, ON7YD – OR7T, releases JT9-2 and JT9-5 software for LF/MF applications

Rik has released software, derived from elements of WSJT-X, which enables communications using the slower JT9 modes – specifically JT9-2 (2 minute periods) and JT9-5 (5 minute periods).

Software available here (Windows): SlowJT9

The only mode of JT9 currently supported in WSJT-X is JT9-1 (1 minute, with various sub-modes)  but in earlier incarnations slower JT9 modes were included. There has been discussion that, with the much increased levels of interest in LF/MF, a revival of the slower modes might facilitate some long distance contacts that are not possible with JT9-1 – this release will enable these experiments to continue.

I’m currently monitoring JT9-2 and JT9-5 on LF and MF and will report any results.

4 Replies to “Rik, ON7YD – OR7T, releases JT9-2 and JT9-5 software for LF/MF applications”

  1. Hi, I have been trying to get slowjt9 to work, no luck. It either crashes or does not decode anything. I have WSJT-X running with same set up, connections, sound card, etc., it works fine. WSJT-X decodes lots of JT9 signals on 630 meters, so I think my set up here is ok? I have tried two different sound cards, Singalink and an ASUS U5, both work with WSJT-X but not SlowJT9? When I am able to get SlowJT9 to run, it will show what looks like, either WSPR or JT9 signals on the waterfall, so I think it is getting audio from the sound cards. I know there are JT9-2 signals locally, in same area few km away, but no decodes?
    If you have any suggestions it would be appreciated.
    Thank you 73

    1. Sorry to hear about your difficulties. I have been unable to decode any JT9-2 either.

      The author of the software requests bug reports and other issues to be reported to him.

      His email is available on the following link:


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