Using FT2 with JTAlert & Timing Requirements for FT2

[Clark L. Stewart]

There was a release recently by IU8LMS of a "Decodium" program (a variant of WSJT-X) which had FT2 as a Mode.  This sparked DG2YCB to include FT2 in the recent release of WSJT-X Improved. 

On Sat, 21 Feb 2026 Uwe stated:

My opinion on this is: Why not try something like this in principle? But then please provide full references to what it is based on and disclose the source code. Keep in mind, that "his" Decodium software is clearly based on a variant of our (now obsolete) joint WSJT-X and WSJT-X Improved 3.0.0-rc1 250915 version. There is therefore no doubt that "his" program falls within the scope of the GPLv3 license. In principle, I fully understand that not every half-baked alpha code is published immediately, but he already advertises “his” FT2 mode quite intensively and also offers downloads for it. Then he is also obliged to provide the source code for it. That's the point.

Unfortinately, IU8LMS's Decodium program is full of bugs or otherwise half-baked code. Furthermore, it contains some "features" I/we do not support, for good reasons

73 de DG2YCB,
Uwe

Laurie, VK3AMA, then posted regarding the program released by IU8LMS that "...the FT2 mode identification character used in the UDP decode messages  . . . uses the "+" character the same as FT4. This results in miss-identification of the decode mode by JTAlert."


Uwe replied that he used the "*" character for FT2 to which Laurie replied:

On 26/02/2026 7:49 pm, Uwe, DG2YCB wrote:

Great. This has now been coded into JTAlert ready for its next public release.

de Laurie VK3AMA
(JTAlert author)

Thus, you will need to download the latest version of JTAlert if you want it to accurately recognize FT2.


And, as noted by Uwe in his release, your TIMING is CRITICAL for FT2 to function properly.  This includes your PC clock and, as Uwe stated in the release email:

Please also note that FT2 has stricter requirements for PC time synchronization (ideally +- 60 ms). Furthermore, your CAT connection should be very stable. Avoid unnecessarily long switching times for your PA or any relays.

73, Clark, W8TN