Issue with 3DR Telemetry Radio V2.1 (915MHz) after Pixhawk 2.4.8 Replacement

I recently replaced my Pixhawk 2.4.8 with the same model and updated the firmware to ArduCopter V4.5.7. While my telemetry system (3DR M10135A, 3DR Radio V2.1 915MHz) worked fine with the previous setup, I’ve encountered issues after the replacement.

Current Status:

  • SiK Firmware: Updated both local and remote radios from 3DR 1060 to HB 1060 using the uploader script.
  • LED Behavior:
    • Local Transceiver: Solid red LED after boot.
    • Remote Transceiver: Flashes green before connecting, then switches to solid red.
  • Connection: I can connect to the Pixhawk via MAVLink, download and change parameters, and telemetry appears to work fine with no dropped packets or communication errors.
  • Performance Metrics: RSSI levels are consistent, and the connection is stable.

Issues:

  1. When attempting to reset either transceiver via ATZ in RFD900 Tools or Mission Planner, the command fails with an error.
  2. LED behavior does not match the expected indications for proper operation (e.g., solid green for a successful connection).
  3. I attempted to reset the radios to default firmware by shorting GND and CTS but observed no change in behavior.
  4. Despite the radios “working,” these anomalies could indicate a deeper problem.

Additional Details:

  • Flight Controller: Pixhawk 2.4.8
  • Firmware Version: ArduCopter V4.5.7
  • Observations:
    • All telemetry packets are successfully transmitted and received with no apparent data loss.
    • Parameters download and update successfully.
    • Communication stability is not compromised, but the LED indications and inability to reset raise concerns about long-term reliability.

https://ardupilot.org/copter/docs/common-sik-telemetry-radio.html#status-leds

Solid red usually means that the radio is in firmware update mode. That’s odd that they are working for you. I’d double check that it’s the right firmware for your radio. Also, are they real 3DR radios or clones? Because the clones are real wild-cards in the functionality and serviceability.

@Allister good point!

@tdyoung6 try this parameter TELEM_DELAY,2 and see if that helps. You can even use the telem radios without the RTS/CTS wires and associated settings, at least as a test.

@Allister It is actually this for the local and the remote is through the same company but links to 3DR.

I thought it was the right firmware and everything appears to work minus RTZ command. I can even reset to default in MP and resets Net ID.

@xfacta I will give that a shot! I can at least edit parameters remotely.

I just checked one of my mRo SiK radios and it’s running:

SiK 2.2 on HM-TRP

I know others are on 2.0

I’ve just used QGC or MP to do the updates on these radios on the odd time that it’s needed it. I just use the default software and it’s worked as needed so I’ve never played with the other firmwares. And the LEDs blink as stated.