FT2 – the new kid on the block

By Mike, G4RAA

No, this isn’t an April Fool joke. There really is a new data mode called FT2, where each transmit or receive sequence only lasts 3.8 seconds. It really is incredibly quick. The mode is about 150 Hz wide, so a lot wider than FT8. The upshot is that there isn’t much space – you can only fit around 18 stations in the 3kHz audio bandwidth of an HF rig. Some rig bandwidths are narrower than that of course, and others wider but you get the idea.

FT2 was introduced in Decodium, a program by IU8LMC that installs on top of WSJT-X. Some of the FT2 specifications online seem pessimistic (only works to -12 signal level, clock timing accuracy needs to be within 50mS). The mode has now been included in v3.1.0 of WSJT-X Improved, a program from Uwe, DG2YCB, one of the developers of WSJT-X. His program includes beta features, many of which find their way into WSJT-X.

I’ve been having great fun playing around with FT2 using WSJT-X Improved. As you can see, at one point, I managed two QSOs in under a minute!

Apparently WSJT-X’s FT4 mode started off as FT2 (in a slightly different implementation) but was deemed insufficiently sensitive, so the signal was made more robust including by lengthening the T/R sequence.

Some people have claimed that Decodium isn’t a terribly good implementation of FT2. I really can’t say whether that is true as I haven’t used the program. Using WSJT-X Improved, timing doesn’t seem to need to be much better than for FT8 – I have decoded signals with timing off by 0.3 sec (ie 300 mS, not the 50mS reported limit.) I have also found sensitivity much, much better than -12. I have decoded signals down to -21 and, as you can see below, I had a QSO with LZ2INP where he was -17 with me and I was -20 with him.

So far I have mostly worked European stations, although I have worked a three US states, Alaska (which counts as a country) and Puerto Rico. I don’t think this is a limitation of the technology – I have copied Japan on 20m – it is probably a reflection of the fact that this implementation of FT2 was a European development.

Although LoTW doesn’t yet accept FT2 QSOs, it is now included in the ADIF log interchange file format specification. I use the Ham Radio Deluxe logbook and it already logs FT2 properly. Hopefully LoTW acceptance will follow soon.

FT2 can be found on 7.052 MHz USB and 14.084 MHz USB. There is a list of frequencies here https://vu3dxr.in/ft2-the-fastest-digital-mode-in-amateur-radio/ but don’t take them (or anything else on the website) too literally – everything about FT2 is Beta at the moment and subject to change!