Title. The radios I am currently using are not 3DR, although that seems to be the overwhelming preference of this community. The radios themselves are able to connect to one another without issue, as indicated by a solid green light (no red light whatsoever), and Mission Planner is able to load the local and remote radio parameters. However, when attempting to establish a connection to the Pixhawk2.1 via Mission Planner, the connection fails throwing "No heartbeat packets received" after 30 seconds.

Successfully loaded parameters:

3691347838?profile=original

Trying to connect to the Pixhawk2.1:

3691348026?profile=original

Notice also that both remote and local radios have a NetID of 71, and that the baud rate for both is set to 57, matching that of Mission Planner's attempted connection. It should also be noted that I have updated the USB drivers multiple times, and flashed firmware to the local radio multiple times. Like I said before, the radios have no trouble talking to each other and my desktop it seems, but struggle to connect to the Pixhawk2.1 itself.

That's the software side of things...

The Pixhawk2.1's 2 telemetry connectors are both 6-pin. The remote radio's connector is 4-pin, but comes with connectors that scale up to 5 and 6-pins. So naturally, I plugged the 4 to 6-pin connector between the remote radio and Pixhawk2.1, but it did not work that way. I then inverted the RX and TX wires, but still could not connect.

The remote radio also came with 6 solder pads on the bottom which I tried in the same manner as the 4-pin connector, but still no dice.

Here are a few pictures of the remote radio:

3691347851?profile=original

3691348040?profile=original

3691348116?profile=original

I'm not certain whether the EN and CF pads on the remote radio are relevant to this problem, I'm guessing they are not.

According to this document, the pinout for the Pixhawk2.1's telemetry ports are thus:

---- VCC_5V

---- MCU_TX

---- MCU_RX

---- MCU_CTS (TX)

---- MCU_RTS (RX)

---- GND

I have tried normal and inverted connections for both sets of TX/RX with the TX/RX wires/pads on the remote radio. I have tried virtually every reasonable configuration for these wires and I get nothing.

It should also be noted that in researching this problem I have discovered other threads and discussions of similar problems, and nothing that worked for them has worked for me so far. Here are a few things I have tried:

- Unplugging the GPS/Compass module during configuration

- Updating firmware on the Pixhawk2.1

- Updating firmware on the (local) radio

- Updating USB driver

- Switching GND and VCC on remote radio

- Restarting Mission Planner after connecting and loading parameters

- Trying the second telemetry port on the Pixhawk2.1

- Changing USB baud rate

If you have had a similar experience, or have a working telemetry system and can point out what I've done wrong, I'd love to hear from you.

- Chase

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  • Alright, everything works now as it should. The problem was that in Mission Planner, under full parameters, I needed to change the baud rate for serial 1 from 9 to 57. I do not know why this is not updated automatically when you change the baud rate in the top right box, but whatever it works now.

    In summary, 5 things need to be configured correctly to ensure connection:

    1) baud rate on local radio set to 57

    2) baud rate on remote radio set to 57

    3) USB port baud rate set to 57600

    4) Mission Planner parameter Serial 1 baud rate set to 57

    5) Mission Planner baud rate set to 57600

  • Actually, not entirely solved. I still have one problem that I am stumped on. If I set the baud rate for everything (radios, MP, and COM port) to 9600, everything works great. But if I set everything to 52600, I can't connect.

    Is it that the radios are not capable of sending data at that rate? Or is there something else here?

  • Solved!

    The problem was that the USB port had a baud rate set to 9600 whilst the radios were set to 15200.

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