I recently switched to the 9XR Radio with Orange RX modeule/ 9ch Reciever DSM2. (Previouly used 9X radio/ with 9ch RF Reciever)
I use an APM 2.5 on a bixler 1.1, with Arduplane v2.70 software.
When doing the intial radio calibration, while adjusting channel 3 (throttle), i noticed that Channel 1 PWM flickers and becomes erratic from 1500 to approximatly 1900 PWM. This ONLY occurs when the Channel 3 throttle is greater than 1500 PWM AND there is NO Channel 1 input being commanded. (For example if i touch only the chan 3 throttle above 50% the chan 1 output goes full PWM, but if i command a chan 1 (alerion) output the erractic behavior goes away)
I can not duplicate this problem with my old RF 9X transmitter /
Reciever.
i also can not duplicate this problem without the APM 2.5
connected to the Reciever.
If i just plug servos into the DSM2 reciever the issue does NOT occur.
The result of this is large uncommanded Chan 1 (Alerion) inputs with
greater than 50% eng power (chan 3). I have demonstrated this on the
aircraft with the engines unpowered and current draw minimal. I have also removed GPS/ Xbee TM/ power monitor to reduce noise.
I am not positive that it is an APM issue, but I cannot confirm its a
radio problem, because it only occurs with APM connected. Can you give
me any ideas or possible solutions to this problem? Has any one else
experienced this? I've got ferrite cores inbound, but i have low expectations that will cure the problem.
Servo Jitter / Channel Coupling Video
Thanks in advanced for any ideas or similar observations
Replies
I had similar problems with the 9XR and Orange Tx module, with Orange 6 and 9 channel Rxs.
The couple was the same, between throttle and channel 1 (aileron), although not as severe as you have described. The channel 1 servo would move to a fixed point as the throttle was advanced past about 40%.
I was using elevon mixing though the APM and an aileron command would cause the channel 1 servo to move erratically and sometimes freeze. The erratic movement wasn't random, just an unpredictable delay between moving the aileron stick and the servo starting to move. The channel 2 aileron movement was normal.
I tried several different Rxs (Orange, Spektrum, JR), disconnected the modem and motor, tested the setup out of the plane so I could route the wiring away from the Rx, tried independent power supplies for APM and servo rail, all to no avail.
Never worked out the exact reason for the problem but the Orange Tx module was the cause in my case. Due to range issues with the Orange module I switched to a Spektrum module and the problem did not occur again. Since there was a severe problem with the Tx it could simply have been interference.
The radio worked normally (apart from lousy range) when the same components were used independent of the APM.
I'm confident in the 9XR with Spektrum module and Orange receivers, had a couple of hundred flights to date with no problems. To fit the Spektrum module I had to grind some plastic off the 9XR case to clear the antenna housing but otherwise it's plug and play.