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[Sticky] FrSky R9 MM 868 MHz Receiver

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Posts: 185
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frsky R9MM 540x400

The FrSky R9 MM is the latest 900MHz mini receiver in the long-range series. It carries on most of the features from the previous R9 Mini receiver, like it’s super low latency, high precision performance in an extremely compact design. A new feature incorporating an inverted S.Port output makes it compatible with more devices.


  • 868MHz(EU Version)
  • Mini size and superlight weight
  • Inverted S.Port enabled
  • S.Port enabled and support telemetry data transmission
  • (Support F.Port, download firmware to support the function)
  • Low latency and high precision
  • With RSSI output in SBUS
  • Battery voltage detection supported
  • Detachable Ipex connector antenna


  • Dimension: 16x10x2.8mm
  • Weight: 1.1g (including antenna)
  • Number of Channels:
  • Non-EU Version: 4/16CH (Telemetry)
  • EU Version: 4/8CH (Telemetry) / 4/16CH (Telemetry) / 4/16CH (No Telemetry)
  • Operating Voltage Range: DC 3.5V – 10V
  • Operating Current: 100mA@5V
  • Operating Range: Up to 10km or above
  • Compatibility: R9M and R9M Lite

All files relating to the R9 mm receiver including manuals and firmware updates can be found here:

Posted : 11/04/2019 12:50 pm
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Posts: 3
New Member

Hi.  I am new here and brand new to FrSky from Spektrum. - Please let me know if this is not the right place for this post

I have just purchased a Horus X10 with 868MHz RF Module and R9mm Receiver with the intention of using it with a Pixhawk 4 Flight Controller in a Quadcopter.

I have connect the receiver to a Pixhawk 4 Flight controller using the Inverted S.Port. The Horus transmitter telemetry display shows the Receiver signal strength and the Receiver battery voltage correctly, but all the remaining telemetry values from the Pixhawk 4 are absent or corrupt.

Some data is too long to fit in the window, and only the mA/h consumed from the battery is changing.

I have also tried the Non-Inverted S.Port but this does not work at all.

Could some wise experience person suggest what I may be doing wrong, of may have overlooked?

Many thanks

Regards Alan K.

Posted : 21/09/2022 6:15 pm
Rich bago
Posts: 96
Estimable Member Admin Registered

sounds like the source of the data, isnt set up for Smart port, have you checked the control board setting?

Posted : 06/10/2022 3:55 pm
Posts: 3
New Member


Thank you for your suggestions.  I found that with the native Pxhawk soft/firmware in the Pixhawk4 FC I could not fully configure the serial port to meet the S.Port requirements.  I have since re-flashed the FC with ArduCopter and the telemetry is now fully working.

Thanks again. 👍 😀  

Posted : 07/10/2022 10:48 am