Review: Frsky Tandem X20 Radio Transmitter

by Oscar

Frsky kindly sent me their latest Tandem X20 radio for review. At the time of publishing, Frsky is still working on perfecting the operating system. In this post I will share the main features and what you can expect from the new Tandem X20.

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What I have here is a pre-production unit, so things could change in the final version, especially the software. If there’s any new features or improvement, I will let you know right away by updating this post.

Where to Buy?

Before purchasing, make sure you choose carefully between FCC (US) and LBT (EU), because the internal antennas are tailored for the different frequencies used in these regions.

Frsky Tandem X20 Radio control gimbals switches buttons

There will be 3 versions, Standard, S, and HD. What I am reviewing here is the Standard version.

The following table explains what features the S and HD versions will have on top of the standard version. Note that the HD will have “built-in 0ms latency HD digital Video Transmission System (720p 60FPS)”, which is super interesting! It’s Frsky’s own HD system and won’t be compatible with DJI’s, I can’t wait to see how they compare :)

It will be using the screen to display live FPV video, and it can output video to your FPV goggles through HDMI which is really neat.

Frsky Tandem X20 Key Features

  • Beautiful build quality – totally live up to its $300 price point IMO
  • NO OpenTX! It’s using a new system called EthOS, developed by Frsky
  • Dual Bands: 2.4GHz and 900MHz are built into the radio
  • Supports external RF module with its Lite module bay (NOT JR), it will support Crossfire in the future
  • Frsky claims the maximum range is up to 50Km to 100KM with ultra low end-to-end latency down to 3ms
  • 800*480 Color Touch Screen
  • It has built-in gyro, you can control an RC vehicle by simply moving the radio
  • Hall-Sensor Gimbals with CNC Metal Panel
  • Weight: 934g including battery

What’s EthOS?

Frsky is replacing OpenTX on their new radios with a new operating system, EthOS. You can learn a bit more about EthOS here:

This is how the Model Setup Page looks like:

Frsky Tandem X20 Radio screen menu interface

After using EthOS for a while now, I find it easier to use than OpenTX, everything has little nice icon, and it’s very easy to navigate and understand even though it’s my first time. OpenTX is a bit more like Linux while EthOS is more like Windows, where EthOS is more graphical.

Mixer tab looks like this:

The user interface of EthOS is super clean, and both OpenTX and EthOS share many of the same features, and so the transition was actually quite easy.

System Settings:

However EthOS is still in its early stage when it comes to development. It’s working as it is right now, but certainly there are still many important options missing. The developers are busy working on EthOS, and there is almost a monthly firmware update – my radio was shipped with 0.0.12 (January), by Feb it was 0.0.15 and now it’s already on 0.0.17.

According to Frsky, EthOS will also support LUA script so hopefully with the help of the community and Frsky, we could use the same LUA scripts for changing Betaflight settings (although it’s no longer a big deal as you can do that in Betaflight OSD anyway).

Currently (Apr 2021) I still can’t play FPV simulator through USB with the X20, a known issue related to EthOS. Right now I could use the XSR-SIM, or Betaflight to play sims. Hopefully this is something Frsky can address before launching the X20.

Tandem X20 Protocol Supports

The Tandem X20 is pretty much intended to be used with Frsky’s latest Archer and Tandem receiver families.

But it will also support older receivers that runs ACCESS protocol, as well as the ACCST 2.0 D16. Note that it’s ACCST V2! It does not support the older ACCST V1 (both D8 and D16). If you must use ACCST V1, you can get an XJT Lite module and plug it to the back of the radio (which also supports L9).

The upcoming Tandem receivers will be using both 2.4GHz and 900MHz frequencies simultaneously, making them a lot more versatile. And the claimed maximum range of this system would be up to 50km to 100Km with ultra low latency, sounds very impressive indeed.

Does it support TBS Crossfire, now?

No, but Frsky is working on it as we speak. Right now, the X20 supports the following external modules:

  • XJT Lite
  • R9M Lite
  • R9M Lite Access
  • R9M Lite Pro Accesss
  • PPM

TBS Crossfire is not on the list yet, also the Crossfire Lite module doesn’t fit in the X20 module bay, because the handle of the radio get in the way of Crossfire’s SMA connector!

Frsky is aware of this issue and hopefully it will be addressed by the time the X20 is released. Personally I want the X20 to support Crossfire so badly as I am so invested in it (9 out of 10 of my quads are Crossfire), if I had to replace all the receivers, that would get really expensive.

Closer Look at Tandem X20 Hardware

The Frsky Tandem X20 looks really professional and the build quality is just brilliant.

Frsky Tandem X20 Radio close up buttons

The screen is a 800×480 color touch screen – it’s intuitive to use and responsive, certainly a great addition to menu navigation. It’s so nice to have when you want to get to a particular option instantly without clicking through a million other options.

The display is bright and the viewing angle is excellent.

There are 8 switches on the X20, the configuration is exactly the same as the other Frsky’s radios such as the Taranis X9D and Horus X10.

There are 6 “Quick-Mode Custom Buttons” next to the menu buttons. The red slider in the centre is just an additional slider on top of the two standard sliders on the sides.

The X20 has internal antennas for both 2.4GHz and 900MHz (hidden inside the radio housing), and there are also RP-SMA connectors if you want to attach external antennas for better range. You can choose which antenna to use in the RF settings.

Frsky Tandem X20 Radio external antenna rp-sma connectors

Between the RP-SMA connectors, there are more connectors under the rubber cover, from right to left: Trainer port, S.Port (SmartPort) for flashing receivers/RF modules, USB-C port for charging and data, micro SD card slot and 3.5mm headphone jack. There are a couple of empty spots in the middle, those are reserved for the more expensive models, such as mini HDMI port for video output.

Note that the Tandem I received didn’t come with an SD card. See my recommendation on which SD card to get for your radio.

There are two momentary buttons on the back of the radio (next to the module bay).

On the back, there’s an external “Lite” module bay (not JR). The radio comes with a 2S 4000mAh LiPo, which can be charged through the USB-C port.

Comparing to the TX16S

The Tandem X20 has all the expected features of a high end OpenTX radio, such as voice read out and haptic feedback (vibration). You can also use the sound pack designed for OpenTX such as the Amber sound pack in the X20, as well as model images designed for OpenTX radios like the TX16S. The Telemetry screen is just as customizable as OpenTX.

Frsky Tandem X20 Radio vs tx16s

Comparing the Radiomaster TX16S to the X20 side by side, the X20 is slightly larger. They both weigh around 935g including battery, but the X20 feels like a more solid radio in hands thanks to the matte, rubbery finish.

Also the X20 feels more balanced when I am holding it, because the gimbals are located in the middle, while the TX16S feels a bit more bottom heavy as the gimbals are located on the top half of the radio.

Although the rubbery, matte finish of the radio looks and feels really professional and high quality, it’s also a “dust magnet” :) You’ve probably noticed how dusty the radio’s got after just a week of use in the pictures.

They even provided add-on grips that you can slide onto the sides, it adds some thickness to the radio if you have big hands and prefer chunkier grips.


I would feel more comfortable using the X20 as a thumber.

As a pincher, I feel like there’s lack of space on the top of the radio to rest my middle finger. I could still pinch with the X20, but sometimes I would accidently hit the switches on the top with my middle fingers, and it’s kind of awkward. Maybe it takes some getting used to.

You can adjust gimbal tension by removing the two rubber covers on the handles, without removing the whole back housing. But it is quite hard to see which screws you are turning. And to get rid of the ratchet on the throttle stick (which is default), you have to take the radio apart to do it.


This is all I have to share for now. You can check the price of the Tandem X20 here:

I will keep coming back to update this post as I learn more about this radio, meanwhile if you have any questions just let me know.

How to update Tandem X20 EthOS Firmware

  • download firmware (.bin file)
  • go into bootloader mode (hold both trim buttons inward then power on radio)
  • Plug in the USB cable (must only do this after entering bootloader mode)
  • Two external drives should appear on your computer (one 8MB, and the other your SD card)
  • Copy the fimrware file to the SD card drive (the one with larger capacity)
  • change the firmware file name to “firmware.bin”
  • unplug USB
  • your radio will detect the firmware file, and starts updating automatically, this should take 30 seconds or so.


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GF 14th August 2023 - 6:32 pm

Hi, what is the RESOLUTION in BITS for the latest FrSky system? I hope it is at least 12bits of encoding?

By Resolution I mean how accurate will the servo track. (The Higher the Resolution, the better).

Older and cheaper Chinese 2.4 GHz systems used 8 to 10 bits and the servo movement was very jerky!

Robey Reed 8th September 2022 - 11:59 pm

What are the least expensive FrSKy RC radio transmitters that will work with MC12/MC12P gimbal extended stick Manual?

Don 17th July 2022 - 12:20 am


Any existing Frsky receivers with S-Bus work this?

Thank you

Doug Bostrom 19th March 2022 - 3:55 pm

Great review

Antonio 10th January 2022 - 11:49 am

Great review! Do you know if Jumper external 4in1 module works with this transmitter? I mean with an adapter for the lite size…. Thanks

Atik 5th November 2021 - 4:55 am

Can it really reach 100km range? did you test it?

Keith Baker 6th July 2021 - 5:51 pm

Great review. I love the ergonomics of this radio and most of all the top mounted color screen. I am ready to buy the thing if it will work with my dozen Frsky V8R7-II receivers without an external module. The V8R7-II receivers will work with with both V8 and D modes. However, I can not determine from any of the dozens of sites and hundreds of pages that I have read if the V8R7-II will work with the X20. Can you help with that answer?

Oscar 6th July 2021 - 8:52 pm

No that receiver is quite old and Frsky doesn’t release any firmware updates for it anymore hence it won’t work with ACCESS or ACCST 2.0. You will need an external JR module if you want to work with older ACCST V1 protocol receivers.
And why not just get the latest Frsky receivers? Easiest solution.

Frederico Seddig 8th June 2021 - 7:55 pm

hello oscar, i configured and installed the x20 for a friend, i really liked the hardware and the touch screen function, it makes programming much easier, but i’m one foot behind i believe frsky won’t have the ability to evolve its fw compared to opentx. I currently use x9d2019 if, I would like to know the opinion regarding the hetos system

Oscar 8th June 2021 - 8:44 pm

Yea the Ethos still has so much to catch up to OpenTX, for example it doesn’t even support Crossfire yet!
I am not really using this radio at the moment until they support Crossfire, but when they do I think I will switch because I really like its ergonomics.

Jason A Jackson 15th May 2021 - 2:55 am

Great introductory review Oscar. Is it me or is this TX a dead ringer for the JETI transmitter? Going dual FrQ it looks like they’re gunning for the Turbine Jet market. Don’t think any turbine guys would take a change on this radio with their 10-15K platforms. However it is a fraction of the price of a comparable JETI transmitter.

Again Oscar great review.

AtomicFrawg 6th August 2021 - 7:49 pm

Turbine guys already use the Frsky x20 and other Frsky transmitters FYI. I recently switched over from using Spektrum iX20 to the Frsky x20s to use in all my aircraft from my Scale 700 Apache to my Pilot rc J10b and all my Giant scale 3D planes. So yes, we are taking a chance on the radio.

Harry 6th September 2023 - 10:01 pm

I really would like to switch as you did do you know if you can get a module to use with spectrum dsmx2 and or srxl ?? Or did you just get all new receivers

John Allen 5th May 2021 - 7:27 pm

2 x Archer RS into RB20, and 2 x R9 Slim into the Archer RS receivers

Gary Shove 27th April 2021 - 11:46 pm

ACCST V1 has a major bug in it, why are you still insistent on using it??? OpenTX touchscreen has been coming for over a year now, and still not here.

Oscar 28th April 2021 - 10:13 am Reply
Simon 26th April 2021 - 11:48 am

You say that it has sma connectors but in the photos they are rp-sma connectors ??.
Which is it,thanks

Oscar 26th April 2021 - 6:27 pm

Yes you are correct, they are rp-sma.

Bill 25th April 2021 - 7:06 am

Nice radio, but to me it’s all about the HD. They claim ZERO ms latency? Anyway the question is, what will HD Vtx and camera cost? Heck, what does the HD radio cost?

Felipe Holanda 15th April 2021 - 12:48 am

Hello, Oscar. Thanks for the review!

I already have a TX16S and I’m looking for a second radio (want better ergonomics). I was thinking about a X20, but X9D SE 2019 is an option too (using r9slim+ in all muito quads). What do you think?

I’m a pincher and the main reason to this second radio is really seeking better ergonomics.

jkmrs 8th April 2021 - 7:51 am

Agreed with the ETHOS comment, I am after the functionality rather than the complex UI. Not so much a problem for drones, but managing a complex set of mixes on a multi servo wing can be a bit trying… :) Would love to hear more about the HD function and related VTXs.
Still it’s too bad it wont support multiprotocol modules. Sure, some of them are not legal anymore (e.g. D8) but some are and in the end as long as the FCC or other local regulatory entity has not shut them down (yet), it still nice to leave the choice to the user. Maybe in 6 month I won’t be able to use it legally, but until then, why not? FrSky still sells the XJT module that supports the “illegal” D8…

Astro 7th April 2021 - 9:14 pm

FrSky isn’t avoiding old protocols. They are following the laws of the EU and USA that they are governed by. Multiprotocol modules do not and will eventually be shut down by the FCC.

ACCST V1 had a checksum bug – ACCST V2 is the fix to said problem. How would you feel if they kept releasing radios with flawed firmware?

OpenTX has been nothing but a hinderance to FrSky – owing your software development to an open-source third-party who is often openly hostile to your company is not in their intrest. Ethos is also supposed to bridge the gap between the complexity of OpenTX and menu-based systems. When you say “I love OpenTX” you probably mean “I love the functionality of OpenTX,” not “I love learning what three different mixing screens do” and “why are my trims reversed.” Ethos is meant to give you the same functionality with a better UI. I wouldn’t be so quick to judge an OS you haven’t even used yet.

Wayne 6th April 2021 - 11:23 pm

FrSky is not avoiding old protocols. They are following the laws of the EU and USA that they are governed by. Multiprotocol modules do not and will eventually be shut down by the FCC.

San Hoong 6th April 2021 - 1:41 am

Hi Oscar,
Thanks for giving your time to review the ground breaking FrSky X20 Tandem. I always use ‘dual redundancy‘ setup ‘ in my 2.6m airplane models hope you can outline how to apply the 2.4GHz/900MHz capabilities to its full potential for dual redundancy. One approach I can visualise is a setup like this: 1 x 2.4 GHz Archer R10 PRO , 1 x 900MHz R9 Slim + OTA going into a RB 20. Your comments please.

Merv Dale 5th April 2021 - 1:09 am

Just a couple of extra bits of info. The X20 series will only ship with a battery if your Country rules allow .
The screen resolution for bit images( graphics) is 300X280 (square) where as previous Frsky radios were 192X126 (rectangular) so if you wish to transfer all you pics to the X20’s they will be distorted .

Jon Barnes 3rd April 2021 - 2:01 pm

Very nice photos in your review Oscar. ?

Oscar 3rd April 2021 - 11:47 pm

Thank you :) I am trying my best :)

Stephen 3rd April 2021 - 10:58 am

Why do frsky persist in avoiding their older protocols when they all work side-by-side in a multiprotocol module? Frsky seem intent on cutting off their own nose to spite their face!
Now they have not only abandoned accsst v1 but also dropped opentx when touchscreen support is due to arrive in literally the next minor release (2.4).
Frsky are so busy abandoning products customers want, very confusing strategy.