Etherkit, OpenBeacon Mini

FT8 Cracked

I’ve got an early Christmas present for you all! In conjunction with today’s final release of WSJT-X 2.0.0 (n.b. I’m not affiliated with that project in any way), I’m pleased to announce that I have now added the brand new 79-symbol FT8 protocol to my JTEncode Arduino library. The new version of the library is currently in testing and not available for upgrade in the Arduino Library Manager yet, so if you’d like to try it out, please download it from the development branch here and install it manually. After I’m confident that all is working well, I will release it to the main branch.

After having a lot of people asking me about it, last week I finally decided to take a crack at reverse engineering the FT8 protocol from the WSJT-X source code. I figured now was a good time since I’m in the final push to get OpenBeacon Mini out to production and a new version of the protocol was coming with the new v2.0.0 of WSJT-X. I had been awfully hesitant to tackle this in the past since all of the modulation algorithms are written in Fortran, a language that I do not know. There are no detailed technical descriptions of the protocol in plain English that I could find, so I would have to depend on reverse engineering the protocol solely from the code.

Armed with a F77 textbook I picked up at Goodwill and lots of Googling, I managed to make a big push over the last 5 days in order to give myself a Fortran crash course and learn how the algorithm works. With a ton of print debugging and by comparing the output of my code to the output of the official ft8code program from the WSJT-X package, I was able to nail it down.

If you are comfortable being on the leading edge of such things, please do give my library a try now and help me test it. It’s nice to see that the JTEncode library has been used in various ham projects out there, and at least once commercial product (other than the upcoming OpenBeacon Mini). I’m sure that the inclusion of FT8 will make it much more useful.

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