Telemetry Radios not finding each other

Hi, I’ve got a set of telemetry radios that won’t speak to each other, I know they used to work a few years back but at some point they stopped talking (probably me messing with settings) and I put them aside but I now want to use them again. I can connect to them both in Mission planner, one over USB, one over FTDI, the settings are identical and I’ve restored to default but they still don’t seem to talk, both just blink green (or the air one blinks red and green when on the pixhawk which I think is not connected but transmitting). Any ideas?

telemetry 3dr radio

Hi I’m having exactly the same problem, did you find a solution? I can’t reflash them either as it says “no port” in Mission Planner.

No sorry, still no luck I was hoping someone here would be able to help.

In the end I ordered a new set cheap online and they work fine with no setup or issues. Hope you can sort yours out or just bin them!

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Thanks, that’s a pain, I wish I knew why they just stopped pairing, I can reflash mine ok which seems mine aren’t as broken as yours so maybe someone else has an idea.

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this happened to me as well.
the problem was that telemetry`s settings had changed so they were not able to synchronize with each other.
i fixed it by configuring the settings with the help of 3dr radio. link to download it is here.

please do not dump your old telemetry. cheers :slight_smile:

I hD to reflash the firmware, and you need a usb to ttl converter for the remote unit, if yours does not have a usb port. Mine did not. Once I flashed both units with the same firmware and settings the worked again.

Thanks but unfortunately I flashed them both to the same firmware and restored defaults on both but still no luck!

I am sure you checked all the settings, but check them again. Also, I tried reflashing mine and nothing was working. It turns out I had QGroundControl running and it was messing up the serial port. I reflash with a python script from the command line. Make sure the format, netid, ecc, mavlink, num chans, duty_cycle, and max window are all the same.

These are the settings, they’re identical, I’ve reflashed them, double checked them and set the defaults.



The only other thing i can think of is to try different firmware. I know mine are format version 27.

I tried updating to v2 firmware and the format changed to 26 (from 25), no joy though so I flashed back to 1.9 and the format stayed at 26. Still no joy either way and all the settings are the same, very frustrating as I’d never even used these in the air, just on the bench a few years back and they did used to work.

Did you get a solution to this ? Facing the same problem

If you connect the air-unit via your flightcontroller and from the flightcontroller via USB with the pc and also connect the ground-unit via USB, you should be able to copy the settings from ground-unit to the air-unit.
This trick saved my day sometime ago.

Best regards,


Hi Maarten

The settings are same in both the units , still they arent connecting . Hoping that someone can provide a solution for the same … all i see are green blinking lights no matter which permutation i apply

Hi there,
Try to change the number of channel on both modules to 15 or 20. Keep the air speed value

Hi George , I just bought a new pair of radios which are not giving me any issues . But I will try your method with the old ones as well and check if that works