Troubles Arming after adding FPV gear to Quad

Hey folks, 

I am having some issues arming my APM 2.5 quadcopter after adding some fpv gear to it.

I have an Deadcat frame, with 1.2ghz for FPV, 900mhz for telemetry, and 433mhz for RC.

I dont really use the telemetry radios, so i am not worried about the the FPV at 1.2 being so close in frequency.

I have one servo for tilt on the FPV cam that is running of my receiver which gets its power through the APM.

When the servo is plugged in the APM goes crazy, mission planner 'ends unexpectedly' and it wont arm at all. I am thinking the servo must draw too much power from the APM, so i guess i will pull the jumper and get an external UBEC to run the servo. In addition, when i connect the APM via usb (no external battery) the servo moves around all by itself with no TX switched on! I wonder if this is caused by interference from the FPV gear. I thought 1.2 for FPV and 433 for RC was safe?

However originally i thought this servo was causing my troubles arming (at the moment the ability to arm it is very flaky/intermittent). When the APM is connected via telemetry radio to mission planner, it will arm every time, then if i connect from MP it will still arm and disarm - but if i just power up the APM and not connect telemetry it wont arm at all! How crazy does that sound?

Any suggestions would be appreciated...


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  • I also just got a 'Pre-arm check mag field' error. I wonder if it is getting these when i am trying to arm the quad.

    I never got those errors before - so how can my fpv gear be causing mag error, and how can i fix it if it is the problem?

    • Can i disable the compass? Using the MAG_ENABLE parameter or do i need the compass to control yaw, or will the accelorometers handle that?

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