Introduction To OpenTX

OpenTX is an open source and free software environment for Transmitters. It is used by thousands of hobbyists and developed by volunteers based on user feedback and requests.

How To Get Started


People approach new knowledge and learn in different ways. Here are some suggestions on how to get started.

  • Read through this page from top to bottom.
  • Skip to the quick start guides below. Read the information provided and watch the videos.
  • Use the manual’s table of contents to jump to a page of the manual.
  • Download and install Companion as explained below; Read the guide; Try out the simulator.

At first there may be a feeling of apprehension and information overload but try and relax. Take frequent breaks but above all else try and try again. When you get stuck ask questions in the Flite Test forums linked to in the help and support section at the bottom of this page.

Is OpenTX For You?

OpenTX is meant for flyers who know a bit about RC but want advanced features available using a computerized transmitter. It is meant for users who are comfortable with computers, trying new things, willing to research how the system works and troubleshoot problems that may occur.

There are many OpenTX users in forums who are willing to help when needed! More…

One major advantage of OpenTX is the Companion PC Software which you can download and try before you decide to use OpenTX. More…

New To RC

Newbies may want to buy a ready to fly (RTF) model and learn how to fly and gain some RC experience before switching to OpenTX.

RTF models come with a basic transmitter that works with the model it came with. Hobbyists usually outgrow this transmitter and buy a second one that is usually computerized. This is the stage at which OpenTX and compatible transmitters become an attractive option.

As a newbie you may still buy an OpenTX transmitter and use the numerous web resources to learn about RC. FliteTest has resources and a helpful community to get you started:

The OpenTX Environment

OpenTX firmware is a software that installs on a compatible RC transmitter. It is the equivalent of an operating system.

The OpenTX environment consists of:

  • A Transmitter
  • The OpenTX Transmitter Firmware
  • The Companion For OpenTX PC Software

The Companion for OpenTX PC software is used to download and write the OpenTX firmware to a compatible transmitter.


Supported Transmitters

FrSKY (free sky) manufactures transmitters, receivers and sensor modules that are compatible with OpenTX. The information on this website is primarily based on their hardware. It is recommended that you buy FrSKY equipment. However there are other brands supported by OpenTX and much of the information of this website is applicable to them as well.

The transmitters supported include:

Various transmitters and DIY transmitter boards supported by OpenTX to varying degrees depending on developer and hardware availability. Being a volunteer developed project support for these transmitters changes over time. Read the release notes for each version of OpenTX to determine if a transmitters has active support.

Where To Buy Transmitters

Buy these transmitters from Amazon Canada, Aloft Hobbies USA, or HorusRC Worldwide.

Aloft Hobbies is an authorized repair facility for FrSky in North America. You will not have to ship your radio overseas for service. Parts and labor are covered for the first year.

Companion For OpenTX PC Software

Companion is the computer application that provides a graphical user interface to:

  • Download and install OpenTX Transmitter Firmware
  • Simulate transmitters and models (Try before you buy or fly)
  • Create and edit real or simulated transmitter and model configurations
  • Backup the transmitter’s firmware, models and SD Card contents
  • Change the OpenTX transmitter start up screen (splash screen)

Download & Companion Manual Links

OpenTX Transmitter Firmware

OpenTX firmware is the software that gets installed on compatible transmitters.

Some of the community driven and supported features include:

  • Telemetry with advanced features
  • User configurable input and channel assignments
  • Mixes that allow for a large number of configurations
  • Actions configurable based on events and values
  • Announcement & Sound that are user configurable including adding custom audio files
  • Custom user images (depending on transmitter)

Download & OpenTX Manual Links


Quick Start Video & Written Guides

Guides for beginners to be able to get started using their equipment quickly.

  1. First Flight Setup – Based on the Q X7 but applicable to other transmitters this guide covers:
    • How to set the sticks to mode 2 (or mode 1)
    • Turning on the radio/transmitter (Tx) for the first time
    • The basic screens and views
    • How to navigate using the buttons and knobs
    • Configuring the Tx
    • Setting up a model
      Note: Companion is not needed to get started and is not covered in this guide. It is however covered in the next one.
  2. Adding & Setting Up A Model by Painless360
  3. Downloading & Installing Companion, OpenTX And The SD Card Contents (Audio, Sounds, Wizards)
  4. Transmitter Stick, Slider & Knob Calibration


Guides, Tutorials & How To’s

This Website

This website has a number of posts categorized by topic. To locate information use the search box and follow the site navigation page.




Keeping This Manual Up To Date

Please help keep this manual up to date. If you find that information is missing, incorrect on unclear please post on this manual’s threads in the forums; Links are provided below in the help & support section.

Help & Support

Donations To OpenTX

OpenTX is provided free for use but it takes money to run the servers and buy equipment for the developers. Please donate to the developers generously and often!


  • OpenTX Manual by the Developers for content taken and given back.
  • OpenTX University for help understanding some concepts.
  • OpenTX developers for help understanding some concepts and responding to questions.
  • Dean Church for feedback.