Setup R9M Module and R9 Mini Receiver in Betaflight

This tutorial explains how to setup the R9M TX module and R9 Mini receiver in Betaflight. The R9M is a long range module that operates on 900MHz band. It’s compatible with most Frsky’s radios including the Taranis X9D-Plus, QX7 and Horus X10.

Here is an overview of the R9M system and how it compares to the Crossfire.

Where to Buy?

You can get the FrSky R9M from these vendors (some are R9 Mini bundles):

R9 Mini Receiver – Beware!

The original R9 mini receiver has the SBUS_IN for redundancy feature. But I guess that’s not being used much so they have decided to replace it with “Inverted S.Port” in the new version – R9 MM.

In the new version, you now have two SmartPort pins, one inverted, and one uninverted. It’s really confusing I know, but basically, you’d want to use the “Inverted S.Port” as shown in the manual for F4 boards, the FC can read it directly without extra inverters or using Soft Serial. This pin is also used for FPort so it’s even more important!

If you are using F4 boards, and getting new receivers, make sure it’s the new version – the “R9 MM”. For F3 and F7 boards it doesn’t really matter as they can understand both uninverted and inverted S.Port signal just fine.

This post explains what “inverted SBUS and SmartPort signals” are.

Buy the R9 MM here:

1. Update Firmware

Update OpenTX on your Taranis to the latest firmware, at least 2.2.2 or newer. For instructions: Tutorial: Flash OpenTX (2.2) firmware to Taranis

And also update the R9 Mini receiver to the latest firmware for bug fixes and improvement. It’s a popular option to flash it to support FPort, you can download the firmware here:

Note: Don’t flash the FPort firmware if you want to use SBUS!

2. Taranis Setup

  • On your Taranis, go to Model Setup page
  • Turn OFF “Internal RF Mode”
  • Under External RF, Mode, Choose R9M
  • Set Failsafe to your desired option, I prefer “No Pulse” as explained in this post

You can also change the power level here: 10mW, 100mW, 500mW, 1W. The lower the power, the longer battery life you will get. Remember, the range should double as power is increased 4 times, theoretically. (Maybe only 2 to 3 times in real life)

Receiver and FC Connection

The wiring depends on what receiver protocol you plan to use. If you have the “R9 MM” receiver with the “Inverted S.Port” output, then you might want to use FPort.

If you have the original “R9 Mini” that comes with the “SBUS_IN” pin, it’s going to be tricky to set up FPort with F4 flight controllers. I see some people use Soft Serial as a work around, and it’s okay for things like SmartPort Telemetry. But I wouldn’t recommend doing it for RC links because the update rate might not be fast enough (not confirmed though). So if you are in this situation, maybe just go with the old method, use SBUS with SmartPort.

For FPort, the connection is only 3 wires: 5V to 5V, GND to GND, TX pin of a spare UART on the FC to the S.Port pin on the Receiver.

Connection Example with Kakute F7

For SBUS and SmartPort, here is the connection:

Follow this tutorial to setup SBUS and SmartPort, it should get the job done and you can skip the rest of this post :)

If you want to setup FPort, please continue with this post :)

Betaflight Settings

Here is how to setup FPort in Betaflight, to summarize:

  • Fire up Betaflight Configurator
  • In the Ports tab, find the UART you’ve connected to the receiver, and enable “Serial RX”
  • In the Configuration tab, Select “FPort” in Receiver Protocol

Testing & Troubleshooting

Now check in Receiver tab if the channels are working (if they move with the sticks), and if you are getting telemetry data.

If the RC link is not working, try changing this setting on and off in CLI:

set serialrx_inverted = ON


If telemetry isn’t working, try setting this on and off:

set serialrx_halfduplex = ON


Also try select “Rediscover Sensor” in your Taranis’s Telemetry Menu.

Still not working? We can help you on IntoFPV forum.

Mounting RX Antenna

Check this guide to learn the different ways of mounting your 900MHz antenna.

10 thoughts on “Setup R9M Module and R9 Mini Receiver in Betaflight

  1. Hessel Prochazka

    Hi Oscar,

    Kinda stuck here. Wired the S.Port pin on the Slim plus (with Fport firmware on it) to TX3 on my Kakute F7. With whatever CLI setting I use for serialrx_inverted I can’t get it to work.

    Telemetry to my taranis works fine.

    Any ideas?

    1. Oscar Post author

      did you flash the right firmware (FCC/LBT)?
      since you are using the “inverted” signal with F7, both serial_inverted and serial_duplex should be on.

  2. Andrea

    With KISS v2, how can I get the RSSI on OSD? I have matek hubosd8se and the RSSI pad connected to S-port of R9mini, but it doesn’t work.. Do you have any suggestion? Thanks

  3. Stefan Näwe

    When talking about SmartPort I think you got it somehow reversed. The R9mm has two SmartPort *inputs* (normal/inverted) and the FC *writes* to one of them. Just my 0.02€…

  4. Taproot

    Thank you Oscar.

    Can you do a review on antenna options to the reciever? I guess many have this setup, but is looking to upgrade rx antenna.


Leave a Reply

Your email address will not be published. Required fields are marked *

Are you Robot? *

For prompt technical support, please use our forum I check blog comments weekly.