Servers by jDrones

Combined RC and Telemetry on a single link (TXMod v2, RFD 900x, TX16S, GCS, Matek H743)

Hello all,

I just wanted to post this thread as I had an interesting time getting this to work and if it can help someone else, then the purpose has been served. Thanks to @Allister and @Yasiinm for helping me with the key pieces of info that helped me get through setting my system up.

My goal was to have both RC and telemetry combined into a single long-range radio link that could be used with the Yaapu telemetry script and supply MAVlink information to a GCS as well.

The high-level steps to get everything working are:

  1. Ensure you are using the correct versions for the software and or firmware, especially on the RFD TXMod and RFD900x. If you have to update them, the TXMod gets updated through its Web interface, the modem through an FTDI cable. These are covered and described in the product documentation
  2. Connect your FC and RFD900x per the connection diagram below
  3. Install your TXModV2 module on the back of your Radio (TX16S in my case) and set the External RF Settings as in the screenshot below
  4. Connect your FC to your PC via USB cable, so you can verify RC link is working
  5. Connect mission planner to your FC using the correct COM port
  6. Under Setup -> Radio Calibration, make sure you can see stick and switches input, etc
  7. Disconnect mission planner from the FC, disconnect USB cable
  8. Change your Wifi settings to connect to the TXMod Wifi, the SSID will look something like TXMOD-XX-XX-XX. Select UDP, then specify the port that TXMod is sending mavlink on, which is 14550 by default. Note: If you have trouble connecting from your ground station, you may need to create a firewall rule on windows to allow UDP connections on this port. I had to do this, using windows firewall & network protection, advanced settings, create an inbound rule. I followed this Youtube video:
  9. Connect Mission planner again, but this time select UDP as the connection, it will ask you to confirm the port number, again 14550. It should read all parameters
  10. If everything is working right, you should now have a single link for RC control, Mavlink Telemetry to your GCS and Yaapu Script on your Tx screen. Follow the link to the Yaapu telemetry script in Github for more information and how to install and set it up.

Necessary start sequence

Note: Use this start sequence to get everything working reliably; (Thanks @Allister! ) otherwise, you may get Yaapu script errors, mostly incorrect flight modes, incorrect battery voltage, etc.) You can read more at that thread

  1. Power up the airplane
  2. Power up the TX16S(TXModV2)
  3. Connect the laptop to the wifi (if it isn’t auto connected already)
  4. Open up Mission Planner.

The hardware I’m using:

Tx Radio: RadioMaster TX16S
Telemetry Radio: TXMod v2.0 with RFD900x bundle
Flight Controller: Matek H743 Wing
GCS: Windows 10 Pro running Mission Planner

Software/firmware versions:

RadioMaster TX16S: OpenTx version 2.3.10-otx, 2020-10-06
TXMod v2.0: Software Version: 1.4.6 - Build date: Nov 30 2020 10:57:11; Internal modem version: RFD SiK 3.16 on RFD900X
Remote modem version: RFD SiK 3.20 on RFD900X (These versions for RFD modems are critical, was having trouble with 3.15 getting RC control to work properly)
FC: Arduplane 4.1 dev version (Was testing FPort telemetry, but latest stable should work)
GCS: Windows 10 Pro
Mission Planner: Version 1.3.74
Yaapu Telemetry Widget 1.8.1

Ardupilot Configuration:
Serial7 (Maps to UART6)
SERIAL7_PROTOCOL = 4 (Frsky SPort)
Serial6 (Maps to UART4)

TX16S External RF settings

Hardware Connections

RFD Modem Settings


This is fantastic! Great job @jimenezlee! I wish this was here when I started using these radios.

As a side note, I’m using Arduplane 4.06 on a Cube Orange and everything here still applies.

And don’t forget to check your failsafes…


This clearly belongs in the wiki


Hi Jorge and Alister,call me MRr Stupid,im trying to set this up and getting connection but it never finishes the param upload,im using the cube orange,ive got the serial wire connected to telem 1 and the ppm out connected to the s bus in,the sbus works good,sodo i leave that as is,and I change serial 1 to 4 sport,many thanks for your great work gentlemen

Telem1 should be SERIAL2. Make sure you have the baud rate correct. What ever serial port you use should also be set to Mavlink.

Servers by jDrones