This tutorial explains how to install and setup TBS Crossfire in Frsky Taranis X9D Plus. I will also show you how to connect Crossfire receiver to flight controller and configure it in Betaflight. The steps should be similar in other Frsky radios running OpenTX.
Further Reading: How to choose a radio transmitter?
Table of Contents
- What’s special about Crossfire?
- Updating Firmware
- Installing Crossfire TX module in the Taranis
- Setup Taranis to use Crossfire TX Module
- Connecting Crossfire Receiver to Flight Controller
- Binding Crossfire Receiver`
- Configure RX from Taranis
- Configure Betaflight for Crossfire
- Mounting Crossfire Receiver Antenna
- How to Setup LUA Script
What’s Special about TBS Crossfire?
The TBS Crossfire is a popular RC system for long range flying.
It’s an external RF module that can be installed directly on the back of the Taranis and Nirvana, so you can still use the powerful OpenTX interface.
The Crossfire operates at the 900MHz band, the low frequency means excellent signal penetration ability through obstacles. That gives you longer range and more reliable signal compared to the typical 2.4GHz we use on racing drones. However, the downside is the longer and larger receiver antennas.
The Frsky Taranis with their “full range” receivers (e.g. the R-XSR and X4R-SB) can theoretically give you 1.5Km range, which is more than enough for most of mini quad pilots. However, there are times we want longer range or simply more reliable signal behind obstacles like trees or buildings, that’s where the Crossfire comes into play.
The other advantage of Crossfire is the lower latency which reportedly improves the handling of the quadcopter according to many well known pilots. We are talking about milli-seconds of differences so you might or might not be able to tell.
The available Crossfire modules and accessories are:
|TBS Crossfire TX Module||TBS Crossfire Micro TX Module|
|– Built-in screen for changing settings
– Max Power up to 2W
– Extra features: Spectrum analyzer, Bluetooth module
|– No screen, settings changed via LUA script only
– Max Power up to 250mW
– Lighter, smaller, cheaper
|Amazon | Heli-Nation||RMRC | GetFPV|
TX Module Antennas
|Stock Antenna V2||Diamond Antenna (Upgrade)|
|– Durable, Cheap
– Can be used for receiver
|– More reliable performance
– Slightly directional – more range in front of the pilot than behind
– Durable design
|RMRC | Amazon||GetFPV | Amazon|
|Crossfire Micro RX||Crossfire Nano RX|
|It uses a JST header for connection||Same capability as the Micro RX, but a lot smaller!
Connection is solder pads
|Amazon | GetFPV||GetFPV | Amazon|
|Crossfire Diversity Nano RX|
|Dual antennas allows better range; Additional features to existing RX|
|Amazon | RMRC | GetFPV|
|Loose Dipole Antenna||Immortal T Antenna|
|– Cheap, simple, lightweight and flexible||– Same performance but stronger, and heavier|
|TBS||Amazon | GetFPV|
Check out our recent review where we compared the two popular long range systems, the Crossfire and the Frsky R9M.
Update OpenTX on Taranis
I recommend updating your Taranis to the latest OpenTX (2.2.1 or newer). Here is how to update OpenTX firmware on your Taranis.
Updating TBS Crossfire Firmware
Update your Crossfire TX module to the latest firmware. To do this, download and install TBS Agent software from here: http://www.team-blacksheep.com/corepro/agent
Launch TBS Agent, and connect your Crossfire TX module to your computer using the Micro USB port.
If there is a newer version detected, click the “Update” button to update the firmware. This should only take a few minutes.
Every time you update the firmware on your TX module, you also need to update the firmware on your RX. This can be done wirelessly using your TX module, we will cover that part in the binding process below.
Since the v2.4 update, the maximum output power of the Micro TX module has been increased to 250mW.
Installing Crossfire TX module in the Taranis
You can install the Crossfire TX module directly in the external module bay in your Taranis. Insert the module into the module bay very carefully, make sure all the pins go into the sockets of the Crossfire module properly.
Beware that the Crossfire module is only fully compatible with Taranis X9D Plus. It also works with Taranis Q X7, and Horus X10S, but there are some minor issues due to the inability of operating at full baud rate, causing problems such as constant warning of “telemetry lost”. There is a DIY mod you can do to fix it.
Setup Taranis to use Crossfire TX Module
Turn on your Taranis, and create a new model for your quadcopter that will be using Crossfire (or just copy your existing models).
Short press the Menu button to enter the Model Setup page, scroll down to “Internal RF” and set mode to “OFF“.
Next set the mode under “External RF” to “CRSF” and change “Channel Range” to “CH1-16“.
Once you’ve done this and exit this menu, the Crossfire TX module should power up (LED lights up on the back).
Connection – TBS Crossfire Receiver and Flight Controller
Remember that almost all of the pins on the Crossfire receiver can be mapped in software. This means you can configure them to output whatever you want, and so there are more than 1 way to connect your RX to the flight controller.
I will show you how I connect mine and map the pins, you can follow exactly what I do here.
- 5V to 5V
- GND to GND
- CH1 (Crossfire) to UART RX
- CH2 (Crossfire) to UART TX
You can use any spare UART on the flight controller.
You can also just connect CH1 and set it up to output SBUS, but I want to use CRSF protocol so you will need to connect both wires in order to get telemetry working as well.
Tutorial: How to setup Crossfire to output SBUS
Note that the CRSF protocol is NOT an “inverted” protocol like SBUS or SmartPort, therefore you must not use dedicated SBUS and SmartPort pins on an F4 FC, which have built-in signal inverter for those pins. However this doesn’t matter on F3 and F7 FC’s as the inversion can be switched on or off in software.
You cannot use Soft Serial either, because they are not fast enough for the data connection.
In this example, I am connecting the Crossfire RX to the UART 6 of the Kakute F4 AIO V2 FC.
Crossfire Micro Receiver:
Crossfire Nano Receiver:
Binding Crossfire Receiver
Pairing the Crossfire TX Module and the RX for the first time can be confusing. It’s easier with the full module because you can read the instructions off the LCD screen.
With the Micro version you have to guess what’s going on by looking at the linking status LED, which is not very intuitive. That’s why I prefer to use LUA script to bind receivers. This LUA script comes with OpenTX 2.2, so you DON’T need to download anything extra :)
Here are the steps to bind the Crossfire TX module and RX:
- Power on the RX, it should be flashing green, which indicates it’s waiting to bind (if it’s LED stays red, press the bind button, it should start flashing green)
- Turn on your radio and run Crossfire LUA script:
- Long press the Menu button on the Taranis to enter the Radio Setup page. Press “page” once to enter the “SD Card” page
- Select the “CROSSFIRE” folder and long press “crossfire.lua”, select “execute” from the dropdown list
- In the next screen, select the only option, “XF Micro TX”
- In the next screen (as shown below), select the second option “Binding”
- You will be prompted the message “Binding…”, It should only take a few seconds to bind, and shows “Binding OK”
- If the RX has outdated firmware, you will be prompted to update it. It will take a few minutes to update the RX’s firmware, once it’s done, the receiver will flash green rapidly for a few seconds (loading firmware), then the green lights on both the RX and TX module will become solid
- Receiver binding is complete
Hit the exit button on your radio to configure the Crossfire Nano receiver.
Configure RX from Taranis
Once your receiver is bound, you should be able to configure it using LUA script.
Long press the Menu button on the Taranis to enter the Radio Setup page. Press “page” once to enter the “SD Card” page.
Select the “CROSSFIRE” folder and long press “crossfire.lua”, select “execute” from the dropdown list.
You can now configure both the TBS Crossfire TX and RX. If you don’t see the option “XF Micro/Nano RX”, it means your receiver is either not bound or the power is off.
The first thing you want to do is configure your receiver output mapping to get it to talk to Betaflight.
To do this, press into “XF Micro/Nano RX”, scroll down to “Output Map”, and change “Output 1” to “CRSF TX”, “Output 2” to “CRSF RX”. That’s it :)
Take a look at the rest of the settings and change whatever you need, the most important thing is to make sure you are using the correct frequency for your region – US should be using 915MHz while Europe should be using 868MHz. Using the wrong one can result in unreliable signal and very low RSSI and LQ.
Mode is the number of channels you want to use, apparently using 8 channels has less latency than 12 channels. Make sure telemetry is on, and set failsafe to Cut so that the motors stop spinning in the event of signal loss, and your quad will drop out of the sky to minimize the risk.
You might also want to set Dst. Channel 12 to LQ so you can monitor signal strength (like RSSI). This is channel 12 or aux8 in BetaFlight. If you set this to channel 8, the BetaFlight aux would be aux4.
Configure Betaflight for Crossfire
The last step is to setup Betaflight to recognize the Crossfire protocol.
Go to the “Ports” tab in the Betaflight configurator, and enable “Serial RX” in the UART you’ve connected to the TBS Crossfire receiver. Press “Save”.
Now go to the “Configuration” tab, under the “Receiver” Section, select “Serial-based receiver“, and select “CRSF” in the second option.
Don’t forget to enable “Telemetry” feature too before pressing “Save”.
Finally, go to the “Receiver” tab, you should now see response from stick movement. This means your receiver is working! If the channels are in the wrong order, just try a different “Channel Map”.
No stick movement? Try this command in CLI:
set serialrx_inverted = OFF
If you are not getting any response at all, go back and check your wiring, Output Map setting for the receiver, and Betaflight configurations.
That’s it, you have successfully setup Crossfire in Betaflight :)
To make sure Telemetry is working correctly, go to the Telemetry page in the Taranis, and select the option “Discover new sensors”, it should begin to pick up data from the flight controller including VFAS (battery voltage).
Mounting the Crossfire Receiver Antenna
If you have been using other radio systems, the first problem you are going to run into is mounting the unusually large receiver antenna. Learn about the different ways of mounting Crossfire antenna and their effects.
Here are some examples of the most popular antenna types including the stock dipole antenna and the Immortal T antenna.
To maximize range and signal strength, try to avoid getting the antenna blocked by the frame. Do not bend the antenna and keep them pointing at the opposite direction will give you the best signal.
You can mount it anywhere on your frame as long as it doesn’t get chewed up by the props, and it hugely depends on your mini quad frame. Don’t forget to search for 3D-printed antenna holders available on Thingiverse.
Setup LUA Script to Change PID & Betaflight Settings
You can install a LUA script that allows you to change many Betaflight settings on your quad, including PID, rates, looptime, filters parameters, as well as your VTX channels and power level!
The setup process is very similar to using SmartPort, except your don’t need to change any settings in Betaflight because we have configured everything necessary in this tutorial (i.e. Telemetry). You only need to following the instructions to download the LUA script to the Taranis, and you are good to go!
Setup LQ and RSSI on OSD and Taranis Warning
Here we will address some of the popular questions.
How many people can fly on Crossfire?
Aoccrding to TBS, theoretically, up to 50 people can fly at the same time using Crossfire. It’s been tested when there are 12 people, the radio link quality becomes noticeably worse but still flyable, so TBS don’t recommend any more than that flying at the same time :)
- Mar 2018 – Guide created
- Jan 2019 – Updated product links and setup detail