Sbus Frsky double receiver strange behavior

  • Hello Powerbox team, yesterday I made some checks on my bench to test a future setup of my system.

    It will be comprised of a Frsky X8R receiver ( 2.4Ghz) and R9Slim ( 868Mhz).

    I connected them to RX1 and RX2 of PB Champion SRS and powered them on, obviously set RX to S-bus.

    Immediately I seen the two dots, in the main PB screen, showing the signals coming from RX, solid white, strange, in my other setup, Graupner Hott, same PB model, there is always only one dot lit,

    if I disconnect the active receiver, it switches to the backup one, right.

    Continuing my tests, and going far from the TX, I noticed that the two dots are not solid, they flichers at very high rate, conitnuing to go far from tx, the connected servos starts to move

    in a casual manner, this is not good, if I put this on my 2.70m model sure it will go to hit the ground.

    Disconnecting one receiver, no difference if is the 2.4 or 868, all works fine even if I am at the limit of the receiver low senistivity threshold, obviousli the antenna fades, and lost frames, increases very quickly till 2048 then stops to count. My thought is that there is some kind of incompatibility between PB and FrSky, S-Bus is a standard but probably there are some differences between PB and FrSky. I heard something similar with Hitec Aurora 9 and Maxima SL rx ( in the Flyingiants forum ). Please have you some suggestions? When Powerbox will support Frsky S-port telemetry protocol? Thanks for your attention.

    Best regards


  • Hello,

    the flickering of the DOTs is normally no problem, this comes from the non synchron receivers signal. But of course if you have faeds counts and the servos are moving crazy this is a problem. Futaba S.BUS receivers are running synchron and the PowerBox is made for that. Maybe this is the problem that FRSKY doesn´t has synchron receeiver outputs when using 2.4 and 900MHz

    Is 18.9 your real version - can you check this again?

  • Hello Richard, no, it is not, but normally I upgrade all my electronics to the latest firmware version. Powering unp Champion the display in the lower right corner shows v07.0, is this information enought?



  • What do yo mean with: The servo's start to move? Do they move randomly or do they switch to a failsafe position?

    It could be an issue with mismatching framerates from the 2.4 and 900 receivers. They are not equal. It should only make the PB skip a frame (hence the flickering dots?) My setup would be 2x RX8R Pro's with one R9Slim+ connected to one of the Pro's. This would ensure the same framerates for both receivers. I don't know if the receivers sync to the RF frames. If they do it would be the same a Futaba does. I doubt FrSky does that. You could ask FrSky but i have not found it an issue with only 2.4 receivers, even different types.

    The only servo movement glitches i have seen were explainable due to a Mercury bug.

  • Tadango: servo starts to move randomly when the signal becomes low, it is not a failsafe.

    My setup is different from yours, I connected an RX8R to RX1 of PB and R9Slim to RX2.

    I also suspected a frame sync problems with the two receivers on different frequencies.

    I will buy an RX8Pro and connect it as per your sestup and re- check all things but I think this will not solves the problem.

    Immagine we have a failure in the RX8R that is connected to the 868Mhz, frames from the 868Mhz receiver will arrive at the same time as the other connected RX8R receiver connected to the other port of PB, I think the problem will reapper, what do you think about?

    Thanks a lot



  • Hello, Richard, at least we have found the problem of software version, thanks ;).

    Please send me your complete address to send it.

    Now I am going to check the second Champion unit, I think is the same, probably you will receive two units.



  • Hello Richard, my second Champion unit has software version V07.2, is it ok? It is installed in an IMAC model and it is not possible to make the same checks of the other unit.

    Now I am going to fill the form