Futaba T8FG PPM/PWM decoder

I have seen a lot of discussion about the need to update the PPM firmware for Futaba Radios.  As I just received my first APM 30 days or so ago- and I am an new to APM, I have some questions:

Can I see want version of the decoder firmware I have on my APM before I upgrade the firmware as seemingly recommended?

How- MP?

 I will be using a T8FG Rx and  either the Futaba R66008 HS or R617FS Rx depending on what I find out here about what Rx is best. Currentely I am planning to use PWM outputs ( One lead per channel) unless advised otherwise. A bit confused here as R6008HS has a" DATA" port and standard servo outputs., but I have never used S-Bus as it's kind of new to me and I  not even sure if the 'DATA" port is usable on this Rx or is the S-Bus output.


All I have done so far is to pug the APM into my PC, launch Mission Controller and calibrate the radio, all with the APM setting on the bench. Was surprised to see that the MP Map showed my den as the location ( ubox) so that seems working OK !   I just wanted to see if it survived shipping. I plan to install later into multicopter, but it will be a few weeks before I have a chance to do so. I have been reading the Boards and would like to thank all of you on your sharing of information. Amazing work from all.


I am sure I will have many other (stupid) questions as I continue my quest to make this all work.

Thanks, in advance,



P.S. Been flying RC since 1970, so kind of used to "issues". AND my stupidly-and crashes!


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  • Hi, just buy a 35$ FrSky TFR4 receiver, and connect the included jumper between channels 3 and 4 as the included instructions say. Now you have a nice 8 channel PPM signal on channel 1 and an RSSI on channel 2. Refer to APM documentation on how to connect the PPM signal - you can either have the PPM encoder forward it, using a jumper again, or circumvent the encoder completely but cutting and reconnecting the PPM/RC5 solder jumpers.
    I wouldn't bother with using the PPM encoder.. Those things always have one more bug somewhere, and the Futaba 617 is a difficult case, as channels 1,6 and 2,7 are output at the same time. You save a bunch of RC wires too. I have no impression of the FrSky having less range or anything than the Futaba. It can do BOTH 7ch and Multi modes, and it has a settable throttle failsafe too.
    Regards, Søren
  • Do be careful when using 7-ch mode receivers (R617 etc), this mode supports failsafe on only one channel (throttle).

    Multi-ch mode fully supports failsafe on all channels though (R6008 etc).

  • Developer

    To check if you need the latest PPM encoder there is a new RC Jitter test in the source repository.


    Either compile and upload it yourself using Arduino 1.0.3 (Autopilot version) or use on of the pre-compiled files that I have included here, and upload using the "Load custom firmware" option in the Mission Planner.

    The jitter test is a APM application, not a PPM encoder firmware. Do NOT try and upload it to the PPM encoder chip using the DFU bootloader.

    After a successful upload, connect to the APM board using the Mission Planner Terminal window (CLI) and let the test run for about 30min. Make sure you do not touch the R/C radio while doing the test.

    After a while your test should look something like this.

    < 00:08:24> -------------------------------------------
    ch1: center:1520 min:1516 max:1522 delta:4
    ch2: center:1542 min:1539 max:1545 delta:3
    ch3: center:1934 min:1930 max:1936 delta:4
    ch4: center:1520 min:1516 max:1522 delta:4
    ch5: center:1851 min:1849 max:1854 delta:3
    ch6: center:1520 min:1517 max:1522 delta:3
    ch7: center:1521 min:1519 max:1523 delta:2
    ch8: center:2074 min:2069 max:2076 delta:5

    If no channel show delta changes above 10, you do not need to upgrade the PPM encoder. If they are much higher (and you are sure you did not touch any of the sticks during the test), you definitively need to update to the latest version (V2.3.16).



  • Yeah, I am wondering that myself as a Futaba guy.

    Which Futaba Rx is safe? Could I use s-bus etc. etc.

    I am having a hard time to get answers. It seems not many people using Futaba gear...

  • I have a T8FG on the way and was wondering the same thing, which is how I bumped into this thread.  Hopefully someone can help us both out.

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Santiago Perez liked Santiago Perez's profile
17 hours ago