How to Setup Jumper T20S Radio | Upgrades, Tips and Tricks

by Oscar
Jumper T20 Radio Transmitter Setup Neckstrap

I will show you how to setup Jumper T20 / T20S radio transmitter for the first time, and get the most out of it. I’ll guide you step-by-step through setting up the EdgeTX radio and also show you some tips and tricks, and potential hardware upgrades to elevate your user experience.

Some of the links on this page are affiliate links. I receive a commission (at no extra cost to you) if you make a purchase after clicking on one of these affiliate links. This helps support the free content for the community on this website. Please read our Affiliate Link Policy for more information.

Still wondering if the T20S is the ideal radio for you? Check out my in-depth review of the Jumper T20/T20S here: https://oscarliang.com/jumper-t20-radio/

Installing Antenna

Ensure that the included antenna is attached before powering on the radio. Powering on the radio without the antenna can cause the RF chip to overheat quickly or even become damaged.

Remember, NEVER turn on the radio without antenna!

Battery Installation

The battery compartment is located on the back. To power up your Jumper T20S, you’ll need either two 18650 or 21700 Li-ion cells. Batteries are not included, but you can purchase them here:

21700 Li-ion cells:

18650 Li-ion cells:

With 21700, it’s a pretty tight fit and it takes a firm push to close the battery bay lid. 21700 cells have considerably larger capacity than 18650, so you should get longer battery life, however they are also heavier which can affect how the radio feels in your hands.

Jumper T20 T20s Radio Transmitter 21700 Li Ion Cell Battery Bay Holder

This battery holder is compatible with 18650 cells too, just pull the contacts outwards so they can hold the smaller 18650 batteries securely. I personally prefer 18650 for its lightweight and weight balance, even though run time is shorter.

Potential Start-up Warnings

To power on, press and hold the radio’s power button for a couple of seconds. You will be greeted by the EdgeTX splash screen.

Jumper T20 T20s Radio Transmitter

Ideally, a brand new radio should turn on without any issues. However, if you are prompted by a warning, don’t panic. Here’s a breakdown of potential warnings and their quick fixes:

  • Throttle Warning: This pops up if your throttle stick (the left one for Mode 2 radios) isn’t at its lowest position when powered on. Pushing it all the way down will get rid of this warning.
  • Switch Warning (also known as Control Warning): This signals that some switches aren’t in their default positions. To clear this, ensure all switches are in their HIGH position
  • Alarms Warning: This appears if the Sound mode is set to mute. If you configure this on purpose, you can press the Enter button (scroll wheel) to safely skip this warning, otherwise enable Sound again in Radio settings.
  • SD Card Warning: This indicates a version mismatch between the SD card content and firmware. If you get this warning, follow this guide to fix it

If everything goes well, you should land on the radio’s default home page.

Jumper T20 T20s Radio Transmitter Power On

Radio Settings

The Radio Settings are where you’ll adjust your display, audio, system related parameters, and so forth.

Kick things off by holding down the menu button for a couple of seconds (the first button on the left of the control panel), this will take you to the TOOLS page. From there, short press the PAGE button twice (the second button on the left of the control panel) to scroll to the Radio Setup page.

Jumper T20 Radio Transmitter Setup Radio Settings

I’ll walk you through the initial changes you might want to consider. Anything I skip over can be left default.

1. Set Date & Time.

2. Battery Range:

  • For Li-ion battery: 6.4V – 8.2V
  • For Lipo battery: 7.4V – 8.2V

Why these ranges? This setting defines the battery indicator on-screen, specifically when it displays as full or empty. You might wonder about the minimum 6.4V for a 2S Li-ion, which can indeed be discharged even more. Yes, you can set it to 6.0V. However, having it a tad higher offers an earlier visual cue. As for the 8.2V max (instead of 8.4V), it’s due to voltage sag. The moment you power up, the battery’s voltage drops slightly. You will never see 8.4V on screen, so think of 8.2V as “fully charged.”

3. Sound:

  • Mode: Opt for “All” to hear “beeps” when navigating the menu. Alternatively, go with “Nokey” if you prefer more silent operation.

4. Alarms:

    • Battery low (threshold for audio and haptic warning, if you fly long range you might want to set this higher so you have enough battery to make your way home.)
      • For Li-ion: 6.4V
      • For Lipo: 7.4V
    • Inactivity: 10 minutes (if the radio is left untouched for this duration, you will hear the “inactivity alarm” audio reminder)

5. Pwr On delay: 1s

This is the time it takes to hold down the power button to turn on the radio.

6. Pwr Off delay: 1s

This is the time it takes to hold down the power button to switch off the radio, this is a safety feature to avoid accidentally turning off the radio. I personally set it to 1s for faster shut down, but if you want to play safe you can set it longer.

7. USB mode: “Ask”.

8. Lastly, press the PAGE button a few times to go to the Hardware page, ensure the ADC Filter option is turned off (unticked). Why? See this section.

Adjusting Stick Travel

One unique feature of the T20 is the ability to increase or decrease gimbal stick travel.

To adjust horizontal gimbal stick travel, simply remove the two screws circled in the following image, and push the metal bracket which limits how much you are allowed to have.

Jumper T20 Radio Transmitter Setup Gimbal Stick Travel Horizontal

To adjust the vertical stick travel, remove the metal covers on the top and bottom of the gimbal, which reveals the screws that limit how far the stick can travel.

Jumper T20 Radio Transmitter Setup Gimbal Stick Travel Vertical

You should always calibrate your gimbals again after adjusting stick travel.

Adjusting Stick Length

Adjusting stick length is a breeze by rotating the screw inside the stick end using a 1mm hex screwdriver.

Jumper T20 T20s Radio Transmitter Gimbal Stick End Screw Height Adjust

Adjusting Gimbal Tension

To customize your control experience, the T20 allows you to adjust gimbal spring tension, but it requires tearing down the radio first. There are 10 screws to remove, and you also need to loosen the two top switches.

Jumper T20 T20s Radio Transmitter Tear Down Screws

Carefully disconnect the ribbon cables before fully lifting the back housing.

Jumper T20 T20s Radio Transmitter Tear Down Ribbon Cables

Jumper T20 T20s Radio Transmitter Tear Down Ribbon Cables Expresslrs Module

Here’s a diagram showing where the gimbal tension screws are for roll, pitch, yaw and throttle.

Jumper T20 T20s Radio Transmitter Gimbal Stick Spring Tension Adjustment Screws Roll Pitch Yaw Throttle

Gimbal Calibration

Before flying with a new radio, you should always calibrate the gimbals.

Navigate to the Radio Setup page, then hit the PAGE button a few times till you land on the “HARDWARE” page. From there, select the “Calibration” option. This will initiate the calibration process for both the sticks and sliders. The on-screen instructions are clear, so just follow along.

Jumper T20 Radio Transmitter Setup Edgetx Hardware Gimbal Calibration

Make sure you only move the sticks as shown in the following image. For best result, avoid moving the sticks in circle. Be as gentle as possible when pushing the sticks, so the radio reads the end points correctly.

Make sure you also move the sliders and rotary switches, set them to their middle position before calibration. You also need to calibrate the 6 flight mode buttons, they are actually treated as a slider in the radio. If your flight mode buttons are not working, chances are you haven’t calibrated them correctly yet.

Battery Voltage Calibration

To ensure you’re getting the most precise battery reading possible, take a moment to calibrate your radio’s battery voltage.

With a digital multimeter in hand, measure the voltage of the batteries inside your radio (while the radio is powered on). Given that the cells are connected in series, you should expect a reading between 6V to 8.4V. The goal is to make sure the measurement on your multimeter matches the one displayed on your radio.

Navigate to the “HARDWARE” page, scroll down until you find the “Batt. calib” (Battery Calibration) option. Using the scroll wheel, get the voltage as close to your earlier measurement as possible.

Jumper T20 Radio Transmitter Setup Battery Voltage Calibration

Flight Mode Buttons Labelling

The T20 comes with stickers for the flight mode buttons. If you fly iNav or ArduPilot, it’s a good idea to label all the buttons to help you remember what they do. This is optional.

Jumper T20 T20s Radio Transmitter Flight Mode Buttons Sticker Labels

Here’s mine.

Jumper T20 Radio Transmitter Setup 6 Flight Mode Buttons Stickers Labels

Switch Covers and Custom Switch Nuts

Jumper T20 Radio Transmitter Setup Switches Nuts Cover

Silicone Switch Covers:

Custom Switch Nuts:

Stick End Upgrades

Jumper T20 Radio Transmitter Setup Stick Ends

I felt the T20’s stock stick ends lack grip, so I upgraded mine to the Sticky360, you can get the M3 version for the T20 gimbals here:

Swapping Switches

Jumper T20 Radio Transmitter Setup Swap 2 Position 3 Position

I swapped the 2-position and 3-position switches, because I normally use the 2-position switches to arm and disarm, having them closer to the gimbal makes them easier to reach while flying.

Neck Strap Balancer

Jumper T20 Radio Transmitter Setup Neckstrap

Due to the location of the battery bay, the T20S is bottom heavy and it won’t balance on the neck strap out of the box. An easy solution is to use a neck strap balancer.

I bought this one a few years back for the Taranis X9D, and it works perfectly on the T20 as well. Get it here:

Model Profile

The T20 comes with a model profile pre-created for you, it’s just called “Model01”. To see the model selection, short press the menu button (top button on the left of the control panel).

While this model has some basic configurations, you need to assign switches in MIXES before you can fly.

To go to MIXES, short press the menu button, then press the PAGE button a few times until you are in MIXES. Go down to CH5, select Edit, and assign whichever switch you want to use for arming. Repeat for CH6, CH7 and CH8 if you wish to use more switches for other things like flight modes, turtle mode and beeper.

If you need help on how to assign switches, here’s my tutorial: https://oscarliang.com/betaflight-modes/#How-to-Setup-Arm-Switch

Here’s the end result of my radio MIXES setup:

Jumper T20 Radio Transmitter Setup Channels Mixes Switches

More tutorials on ExpressLRS:

Creating a Profile for FPV Sims

Planning on practising in an FPV simulator? Consider creating a dedicated model profile for this purpose.

Radiomaster Pocket Radio Transmitter Setup Fpv Simulator Model Profile Internal External Rf Disabled Off

To do this, start with making a duplicate of your existing model profile for your drone. Then change its name to something else such as “FPV Sim” or just “Sim”.

In Model Setup, scroll down and switch both “Internal RF” and “External RF” to OFF. This will save battery life when you are playing FPV sim and prevents the internal RF modules from getting hot.

Backup and Restore Radio

I recommend backing up your radio settings regularly (e.g. before firmware updates and whenever you make big changes). Fortunately, with EdgeTX, backing up and restoring your radio’s settings is simple and hassle-free.

Normally, EdgeTX radios use a micro SD card to store everything (aka SD card content), but the T20 has a onboard memory chip for this.

Follow instructions here to backup and restore your radio SD Card Content: https://oscarliang.com/backup-restore-models-radio-settings-edgetx/

Easy Volume Control

Your Jumper T20S is equipped with two rotary controls in the control panel (S1 and S2). They might not be useful for people flying multi-rotors, and we can turn them into a volume control. The trick is to create a function in the radio. You can either do this in “Special Functions” in the Model Setup, or “Global Functions” in the Radio Setup. I prefer to do this in Global functions because it applies to all model profiles, saving you the need to set them up individually for each profile.

Jumper T20 Radio Transmitter Setup Edgetx Global Functions Volume Rotary

  1. Navigating to Global Function: Hold down the Menu button, then a few taps of the “PAGE” button will take you to the “Global function” page.
  2. Creating Function: Find a empty slot and select “ON”.
  3. Setting Up Volume Control: In the 2nd parameter, select Volume, in the 3rd parameter, select the rotary control by moving it with your fingers, and finally enable it by ticking the box.

Updating EdgeTX

Backup your SD card first before updating EdgeTX.

1. Checking Firmware Version: Navigate to the system menu by heading to Radio settings => Versions. This step helps identify the version currently running on your radio and whether you need to update.

2. Using EdgeTX Buddy: This online tool is the most user-friendly method for updating the EdgeTX firmware. For a detailed step-by-step guide on using it, refer to: https://oscarliang.com/flash-edgetx/.

Updating Internal ExpressLRS Module

If you have the ExpressLRS (ELRS) version, updating the internal module is easy. The procedure is identical to the Zorro: https://oscarliang.com/update-zorro-elrs-firmware/. Here’s a summary of the steps:

  1. Connect the T20 to your computer using the top USB-C port. Opt for the “USB Serials (VCP)” mode.
  2. Download, install and run ExpressLRS Configurator program, choose “Jumper 2.4GHz” as the device category and select “Jumper AION T-20 2.4GHz TX” as the device.
  3. Build Options:
    1. Go with EdgeTXPassthrough as your flashing method.
    2. Set your regulatory domain. For instance, use ISM_2400 for FCC users.
    3. Enter your unique binding phrase
  4. If flashing via USB, click “Build & Flash”.

Jumper T20 T20s Radio Transmitter Expresslrs Firmware Device Target

Tips and Tricks

Custom Sound Pack

Bored of the default voice prompts? Try custom sound packs. Amber Sound Pack, for instance, stands out with its superior sound quality.

Download: http://open-txu.org/home/version-2/v2-2-resources-2/

After downloading, extract the files and replace the originals in the SOUND/en folder on your SD card.

Playing Custom Sounds

Did you know you can play custom sound files, even your favorite tunes, on any EdgeTX radios? If you’re new to this, here’s a tutorial to create custom sound files for OpenTX radios, the same steps apply for EdgeTX: https://oscarliang.com/taranis-play-sound-track-mp3-files/

Filename limits: Ensure the filename is no more than 6 characters, with the file extension capped at 3 characters. Also, dodge any special symbols in the name. The ideal file format: 32000kHz Mono Wav.

Exploring the Tools Page

The Tools page on your EdgeTX radio is a collection of useful LUA scripts. One frequently used LUA script is ExpressLRS, which allows you to configure your ExpressLRS module.

Jumper T20 Radio Transmitter Setup Edgetx Tools Lua Script

Button Cell Battery Replacement

Jumper T20 T20s Radio Transmitter Tear Down Pcb

If your radio is constantly forgetting the date and time settings, it’s likely the button cell battery is dying. Look for a Lithium 3V CR1220 battery. Conveniently, you can get them online, for instance on Amazon (affiliate link): https://amzn.to/3yDyDBe

Upgrading to AG01 Gimbals

You can upgrade to the AG01 gimbals, here’s my step by step tutorial: https://oscarliang.com/install-ag01-t20s/

Switch Rockers and Knobs Upgrade

Rc Remote Radio Transmitter Metal Switch Rockers Knobs Upgrades

Rc Remote Radio Transmitter T20s Metal Switch Rockers Knobs Upgrades Screw Install

Rc Remote Radio Transmitter Metal Switch Rockers Upgrades T20s

Rc Remote Radio Transmitter T20s Metal Rotary Knobs Upgrades.

Purely aesthetic upgrades, but do look nice.

Shell Replacement

Different housing design, especially around the gimbals, no more “recessed” gimbals. Also comes with translucent plastic ring that adds more depth and for LED mods. Comes with transparent and grey color options.

Conclusion

We hope this guide has been helpful in setting up your Jumper T20/T20S radio. I will be updating this guide if there are other useful mods and upgrades.

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28 comments

Seba 20th February 2024 - 4:08 pm

Does this radio support crossfire?

Reply
Oscar 20th February 2024 - 4:11 pm

Yes it does.

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Łukasz 11th January 2024 - 8:33 am

Hi, how do you rotate hook in radio to mount this model of neck strap balancer?

Reply
Oscar 11th January 2024 - 1:30 pm

There’s a nut inside the housing that you can loosen.

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Łukasz 15th January 2024 - 9:01 am

Thank you :D

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Eddie 30th December 2023 - 7:33 am

Can you add the details of the wiring of the external module socket. I have the irx4 lite muti protocol that i would like to wired it to..

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zen 14th December 2023 - 7:07 pm

Hi oscar, I have not used this radio for two months, now the screen just blank no activity or light.. any ideas? it boot fine, theres edgetx booting sound and switch warning.

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Stacy Rodriguez 13th November 2023 - 1:12 pm

Do you know if EdgeTX is planning on updating the Jumper T20s to 2.9 anytime soon?

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Kyle 13th November 2023 - 12:51 pm

I am having issues with “Loading..” stuck with the expresslrs script.
You don’t happen to have a backup of the stock SD card contents? I accidentally deleted my backup.

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sNi-FPV 25th September 2023 - 10:08 pm

Thank you for a great review! :) I just bought one. However, I wonder if the two (silver) “latching” buttons on the top can be modified to to be momentary switches instead? Do you know if it’s possible to just remove the latching function on those switches?

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Oscar 26th September 2023 - 12:16 am

I am not entirely sure, but i don’t think it’s possible. Might need to replace them with real momentary switches.

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sNi-FPV 26th September 2023 - 11:28 am

I fixed it already, it’s not an “easy” thing, but doable… :) You have to dismantle the actual switch behind the physical button you press and remove the small “latch-wire” inside the actual switch…

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GO 21st September 2023 - 10:20 am

Does it support ELRS backpack?

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BISOP 17th January 2024 - 1:44 am

uP!

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Yith 11th September 2023 - 11:30 pm

I have been very interested in the extra switch holes under the rubber bungs but I have yet to see any sign of anyone attempting to add any extra switches to the radio in those.

I was thinking it would probably be easier to effectively replace a couple of the pots with switches in those holes. I mean 6 pots is a little overkill!

How easy do you think this would be to do?

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Sunkione 28th January 2024 - 4:19 am

I want add more switches to I seen 2 connectors inside but they are on different board. Also mine RSlider its faulty and can’t calibrate. Radio looks solid and i like the form factor. 2 extra switches will make big difference to me. Its weird originally there are 8 switches unlocked in menu but only 4 are physical available.

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sen 10th September 2023 - 12:26 am

Hi, i cant seem to find T20 in the edgetx dropdown list of radio, so does it mean i cant update the edgetx for now? thanks Oscar

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Oscar 10th September 2023 - 1:33 pm

EdgeTX Support for the T20/T20S isn’t in 2.9 yet, it’s coming in the next release 2.10.
For now you can just leave it on the stock firmware.

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JC 6th September 2023 - 4:47 pm

Great content – super useful, thank you for sharing. What size are the nuts you used for the switches?

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Oscar 10th September 2023 - 1:01 pm

I’m not 100% sure about the size, but they are the same one used on the TX16S/Taranis/T16/Boxer. They all use the same switch sizes.

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Andrew 4th September 2023 - 11:28 am

Tried to update the elrs module to 3.3.0 via wifi and got this error: Targets Mismatch
Current target: JUMPER_AION_2400_T-PRO_TX.
Uploaded image: UNIFIED_ESP32_2400_TX.
Rechecked and rebuilt the firmware but the error persists. Is it ok to proceed or there’s something wrong?
And how did you get drivers for USB Serials (VCP) mod? Thanks

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Oscar 4th September 2023 - 4:45 pm

I flashed via USB so didn’t get that error, but I think it should be ok to proceed because the target is different in the new version. The old target was T-Pro but the new target is T20.

Regarding driver, You might need to install CP210x Driver (Download: https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers). I tried standard windows driver as it comes with an installer, version 6.7.6 seems to work fine.

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Aldo 17th January 2024 - 10:47 pm

Hey Oscar,

I installed the drivers but still get only the COM5 Microsoft. Do you have any idea why would it be?

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Clay 28th January 2024 - 2:49 am

Same, here only com 4 microsoft

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Marcel 5th February 2024 - 9:56 pm

Same for me, only COM4 available and fails to open it when i try to flash. Anyone got a solution?
Seems like drivers won’t install properly.

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Dave Downunder 29th August 2023 - 9:45 pm

Hi Oscar… Always seem to find your reviews when researching new toys before purchase, thanks for the information. Just a thought, some of your readers (like me) are looking to confirm how hard it will be to convert from mode 2 to mode 1… Info on swapping ratchet and springs on the gimbals along with if the option is in the menus would be a fantastic addition to your reviews… Thank you

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Oscar 3rd September 2023 - 1:24 pm

I haven’t tried changing it from mode 2 to mode 1 myself, and I have no plan of doing it as I don’t fly Mode 1. But just based on observation it should be possible. I think you just need to move the throttle friction bar over to the other gimbal, as well as moving the screw that disables the vertical gimbal spring.

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[email protected] 29th August 2023 - 3:14 pm

Bagaimana cara upgrade Jumper T20 ke ELRS versi 3.3

Reply