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.

R9M TX Modules

R9M Module R9M-Lite Module
– Full Size JR Module
– Max Power up to 1W
– Designed Specifically for the X-Lite
– Max Power up to 100mW
– Lighter and smaller
Banggood | GetFPV | Amazon HorusRC | Banggood | RDQ

TX Module Antennas

900MHz Duct Antenna Super 8 Antenna
Cheap and robust Slightly higher gain (3dB), lighter and smaller
HorusRC | Banggood Banggood | HorusRC | Amazon

R9 Series Receivers

R9 Receiver R9MM / Mini
Robust, servo connectors, MMCX diversity antennas The lightest and smallest R9 series receiver
RMRC | Banggood Amazon | Banggood | HorusRC
R9 Slim R9 Slim+
Just as good as the R9 but slimmer. Basically R9 Slim with diversity antennas
Amazon HorusRC | GetFPV

R9MM Receiver Antennas

Loose Antenna Dipole T Antenna
Cheap, Simple, Lightweight, and Flexible mounting More durable thanks to the plastic tube
HorusRC | Banggood 915MHz: BanggoodHorusRC
868MHz: Banggood

R9 Mini vs. R9MM

Frsky released a new receiver, R9MM. It’s basically the R9 Mini, with the “SBUS_IN” pin replaced with the “Inverted S.Port” pin.

It’s the go-to RX for F4 flight controller users, because you don’t have to worry about signal inversion anymore. For F3 and F7 users it really doesn’t make a difference.

Not sure what I am talking about here? See this post “inverted SBUS and SmartPort signals“.

Which Receiver Do I have?

I have both R9MM and R9 Mini receivers in the same pile, and they look identical! Here is a little trick of mine to tell them apart.

The only difference I can see from the outside, is the silkscreen. The R9MM has a recognizable letter “S” on the Inverted S.Port, while the R9 Mini doesn’t.

Update OpenTX

It’s best to update OpenTX on your Taranis before using the R9M module.

Especially if you want to use the “FLEX” firmware, you have to use OpenTX version 2.2.3 or newer. For instructions: Tutorial: Flash OpenTX (2.2) firmware to Taranis

If you do decide to flash the “FLEX” firmware, make sure to select build option “FLEXR9M” before downloading firmware.

Update R9M Module Firmware

Download the latest R9M Module firmware here: https://www.frsky-rc.com/r9m/

Which Firmware Should I Use?

There are the Normal firmware, and the new Flex firmware.

The Flex firmware offers the following benefits.

You can switch frequency in the radio setting between FCC (915MHz) and EU-LBT (868MHz). It can be a pain with the normal firmware as you are locked to a specific frequency, and it requires re-flashing if you want to change it. Not that you will need to do that normally, but it’s just convenient, say if you travel to another country with your quad.

It also allows maximum power up to 1W, and now you get telemetry on all power levels, that’s probably the best feature.

I can see Flex firmware taking over in the future, but it’s still kind of experimental as far as I know. There were some complaints about failsafe in the past and Frsky has since released a number of updates to improve reliability. Anyway use it at your own risk.

Copy Firmware File to SD Card

Unzip the file you just downloaded, and the firmware file should have .frk file extension.

Put the firmware file on the SD inside the Taranis, inside the folder “Firmware”. Create one if it’s not there.

Firmware Flashing

In your Taranis, go to Radio Setup (long press the Menu button). Press Page button once to go to the SD Card page, and find the folder “Firmware”.

You should see the firmware file you just copied here.

Hold down the Enter button, you should get a list of options, choose “Flash Ext. Module

The flashing will begin, and the screen should say “Writing…”… The R9M module LED will flash Green and Red rapidly during this. It will take a minute or two.

Update Receiver Firmware

Download the latest R9MM receiver firmware here: https://www.frsky-rc.com/r9-mm/

Follow this guide on how to flash Frsky Receiver Firmware.

Note: FPort firmware allows you to use FPort, instead of SBUS and SmartPort. Don’t flash the FPort firmware if you want to use SBUS!

Taranis Setup

  • On your Taranis, go to Model Setup page
  • Turn OFF “Internal RF Mode
  • Under External RF, Mode, Choose R9M

According to your region, select FCC / 915MHz or EU-BLT / 868MHz.

You can also change the power level here: 10mW, 100mW, 500mW and 1W (Auto). The high the power, the less battery life you will get. Remember, the range is only double as power is increased 4 times in theory. And when using 1W power you should plug in an external 2S LiPo at the back of the module.

For the R9M Lite module, you might see higher power options in the menu, but this module is only rated for maximum 100mW. Setting it to higher power won’t do anything. So don’t get too excited.

Finally, set Failsafe to your desired option, I prefer “No Pulse” as explained in this post

Current draws vs. output power:

  • Taranis internal module 120mA
  • R9M 10mW 170mA
  • R9M 100mW 210mA
  • R9M 500mW 320mA
  • R9M 1W 370mA (without external battery)

Receiver and FC Connection

The wiring depends on whether you want to use SBUS or FPort protocols. I personally prefer FPort because it’s simpler to setup.

For FPort connection, there are 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

Please see my tutorial how to setup FPort for more detail.

Connection Example with Kakute F7

For SBUS and SmartPort, here is the connection. If you don’t know how to setup SBUS and SmartPort, please follow this tutorial.

Mounting RX Antenna

For the stock loose antenna on the R9MM, I just use two pieces of zip tie wrapped around the arm, and secured by heatshrink tubes.

For the Dipole T antenna, here is how I do it with two zip ties.

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

Display RSSI in OSD

One cool thing about FPort is that RSSI works automatically! The only thing you need to do in Betaflight is changing the scale to 200%:

set rssi_scale = 200
save

Then enable RSSI value in OSD.

If you are running SBUS, follow this tutorial to setup RSSI and display it in Betaflight OSD.

Edit History

  • Oct 2018 – Article created
  • Feb 2019 – Updated product, instructions and info about Flex firmware

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

  1. Doug Loshbaugh

    Thanks for your excellent tutorials, including this one!

    I ordered the R9 MM directly from FrSky (R9M/R9MM promotional combo), and it has a carrot over the inverted S-Port pad, not an “S”. It looks like your photo of the R9Mini. I’m not sure this matters, since it appears there is one firmware download for both on the FrSky web site.

    I had a terrible time figuring out which firmware to download for both the R9M and the R9MM. The R9 and R9M-{ite firmwares e are listed together with no apparent labels, and to make things even more confusing the downloads for the R9M-Lite appear in the Download folder label “Ranger9”. It appears the only way to tell which one is correct is to download and check the file name afterwards. In the R9MM downloads, both receiver and transmitter firmwares are listed without clear labeling. I’m still not sure I picked the correct files. I wish FrSky would label them better!

    Reply
  2. Vincent

    Hello Oscar,

    Thank you so much for your Tutorial. So In my case i have A Xrotor G4 f2 and a R9mini. On this flight controler there is a SBUS pad . So i connect Sbus receiver on the Sbus FC and the Sport receiver to a TX 1 (for example) And after in Betaflight i activate SMARTPORT on UART 1?

    Reply
  3. Matty Robbins

    Hi Oscar, I am getting really low range when using the R9M + R9MM , I already changed antennas and receiver but still range in no more then 300m when the RSSI drops drastically. Any ideas?

    Reply
    1. Oscar Post author

      Using the right frequency? have you tried a different RX just in case?
      Please join IntoFPV.com for troubleshooting, thanks!

      Reply
  4. Adam Bowler

    Wait a sec…If i’m trying to use FPort on the R9mm I DON’T use the pin labeled “S.Port/F.Port” I’m supposed to use the one labeled “Inverted S.Port”?

    Reply
  5. Mindaugas

    Hi Oscar,

    it is OK with module (R9) if radio is powered from 3S lipo battery? because as I understand there only external module power supply recommendation to not use more than 2S lipo.

    Vin Voltage Range: 4V-12.6V
    External Power Supply: 4V~12V (2s Li-Battery is recommended )

    Reply
  6. 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?

    Reply
    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.

      Reply
  7. 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

    Reply
  8. 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€…

    Reply
  9. 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.

    Reply

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