Question regarding antenna fades and lost frames

  • Dear PowerBox Systems,

    I've been using a Champion SRS with two Futaba r7003sb receivers and a T18MZ in my 7 m ASH31 since 2014 and I'm very happy with the system.


    I had a couple of initial problems getting the telemetry going and got great help from Richard Deutsch, see a earlier post in this forum (Problem with Champion SRS, Teleconverter and T18MZ)

    At the time, I decided to not send the unit in for upgrade of the signal controller which means I'm still running V5.3.

    As far as I know I have never experienced a hold, but I do see that the counter for antenna fades and lost frames reach maximum rather quickly each flight. I believe that the installation of the antennas should be adequate and provide nice reception. Richard suggested back in 2014 that "An update here in factory would help to make the Lost frame/ Fades data showing correct values", but at the time I wrote the question I did not understand what he was referring to because my problem was related to lack of telemetry data via s.bus2.

    For a long time, the telemetry data converter from Futaba did not work on my computer so I never been able to analyze the data recorded on the memory card, but I have noticed that the counter for antenna fades and lost frames typically max out after having flown a flight with my glider. I recently found that the latest data converter software from Futaba seems to work and decided to have a look at the data. I see that the number of antenna fades and lost frames quickly increase and it does not appear to be strictly related to the altitude/distance between my transmitter and the plane. I also notice that the number of lost frames do not seem to increase monotonically.

    In example 1 below, the antenna fades max out after 25 min / 40 min. The lost frames max out after ~22 min, but no holds were observed.

    Many of the antenna fades and the lost frames appear before the plane took off from the ground.

    In example 2 both RX 1 and 2 antenna fades reach max after < 20 minutes and the lost frames reach max after ~12 minutes.

    Interestingly enough, the difference between each timestamp for the telemetry data points stored in the transmitter seems to never exceed 1.25 s which indicate that I do get a continuous stream of telemetry data back to the T18MZ.


    1. Is the number of antenna fades / minute reasonable or caused by poor receiver reception?

    2. Will upgrading the signal controller to the latest version make a difference when using r7003sb receivers?

    3. Why does the "lost frames" counter not increase monotonically like the antenna fades?

    Best regards,

    Per Takman

  • Thank you for the information Richard!

    I might consider postponing the upgrade a bit longer since the flying season is now fully on with lots of meetings to attend.

    Did you notice that I use 2x R7003SB receivers? Do they need to be upgraded as well? The link above only refer to R7008SB receivers.

    Do I just use the form on your website to prepare you for sending it in and state that I wish to upgrade the unit and receivers?


    Best regards,

    Per Takman