Can't get 915MHz radios to connect (Solved)

Ok, I read through the wiki a dozen times.  I can't my ground and air radios to connect.  Is it necessary to connect the air radio to my laptop with a serial to TTL cable and save the settings to that radio before it can connect to the ground radio?

SOLVED- see my post on page 4.

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  • I recently ran into a similar problem but I think my symptoms were a little different from what has been described here. I use a laptop for telemetry, but the battery isn't what it used to be so I bought a UPS for the field. Being the thorough geek that I am, I loaded the USB Battery drivers so that I could see the actual charge on the UPS unit. When I got to the field I was unable to use my telemetry despite getting green link lights on either side of my 915MHz links.

    What seems to have happened it that the UPS battery loaded a driver that seemed to arbitrarily change and connect to any software based COM port driver. I couldn't just "close" the offending program, I had to go into services and manually shut down the service before I could connect to my telemetry links again.

    I expect this type of behavior could easily happen with any other device that loads virtual serial drivers into your computer. Between UPS, Arduino units, USB-to-Serial adapters something could easily change your COM port settings or connect to your port effectively locking you out. Beware that you may not be actually connecting to the COM device you think you are.
  • I still can't get the radios to connect.  Here's a screenshot of my com settings and Mission Planner settings.  I don't see the settings for the air radio on MP.


  • Hey Monroe, thanks for the post. I saw the previous settings, but i have a feeling that i screwed up the settings, so they won't accept the stock settings. Unless I have the net ID wrong, i already checked the other settings. I will try changing the ID back to 25. Any other suggestions?

  • OK- I tried a different laptop and same results- the radios are not connecting.  So what's next?

  • Similar problem.  APM1, 915MHz radios.  When I do Ctrl-A, I can only get info from the ground unit.  The air unit won't connect.

    The strange thing is the green LED on the ground unit is blinking, indicating it's looking for a radio.  But the air unit is solid green, saying it's connected to something???  But then every once in a while, it switches over to solid red for a few seconds, then back to solid green.  Also, when it's solid green, the red LED blips quick about once per second.

  • 3D Robotics

    No, the radios should connect right of the box, unless you've changed the settings on the ground one (ID, etc) but not the other.

    Are you saying that they won't connect at all (when you load settings from one in the MP, it doesn't show the settings from the other, too), or just won't connect via MAVLink?

    Needless to say, they won't connect if you're powering APM2 via the USB. 

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