TX16S Removable Antenna Mod

by Oscar
Published: Last Updated on

The Radiomaster TX16S is a great radio, but you can’t remove/swap/upgrade the antenna for the internal multiprotocol module. In this tutorial, I modified my TX16S with a SMA pigtail so it has a removable antenna.

My full review of the Radiomaster TX16S Transmitter.

Warning: This DIY hack has not been approved by the manufacturer. If you decide to follow the instructions in the post, do so at your own risk, I take no responsibility for any damage caused.

I want to be able to remove the antenna from the TX16S radio, so it fits better in my bag and doesn’t damage the antenna. This also allows a higher gain antenna to be used, but make sure to check your local regulations before doing so.

What You Need

These are the screws I am using (black ones), it doesn’t have to be this type, I just happen to have these and they fit. The silver screw is from the TX16S housing, for comparison.

Optional

Anti-static wrist strap: https://amzn.to/2Z5D1IC

Not necessary but recommended, it helps protect sensitive electronics from static. If you don’t use this, make sure to “ground yourself” to discharge static electricity by touching grounded conductive surface.

SMA / RP-SMA Male to Female Adapter: https://amzn.to/318tym7

SMA connectors have finite mating cycles (about 500 times), RF performance will decrease over time the more you remove and install the antenna. Over-tightening the antenna can also reduce lifespan.

It’s not uncommon that some people get an SMA adapter between the antenna and pigtail, so it will only wear out the $2 adapter and not the pigtail. However the adapter will result in a slight signal loss, it’s no big deal if you don’t push your signal limit often, but that’s your call.

Antennas Options

Steps

Take the TX16S apart by removing the 4 screws on the back, and two screws on the top. You also need to remove the two rubber plates on both sides.

This is how the original antenna is installed in the TX16S.

The antenna connector and coax wire are glued to the board, but this can be easily removed with a pair of wire cutters.

The coax wire is cable tied to the plastic strut.

Now, remove the antenna wire from the board. Antenna connector is U.FL (IPEX).

Squeeze the end of the antenna and push it out of the top plate.

By looking at the two unused screw holes, I have a feeling that the radio was originally designed to have removable antenna, but somehow it didn’t happen in production.

Insert the U.FL to SMA coax cable into the 3D printed holder. You should leave the wide washer in the SMA connector, it will help prevent the SMA connector from being pulled out of the antenna hole.

Install the holder on the top plate.

Connect the UFL cable on the PCB. Zip-tie the coax to the same strut.

Hot glue the exact same spots to secure the coax cable.

While we have the radio taken apart, why not adjust gimbal spring tension too? :)

Now we can put it all back together, and we have it :)

Make sure you put antenna on before powering up the radio, and that your antenna connector matches the one on your radio. Otherwise you could fry the transmitter module due to overheat.

Also you might want to fine tune the frequency for your internal RF module for maximum performance.

Broken IPEX Connector

If you have a damaged U.FL / IPEX antenna connector on the RF module, you can purchase a new RF module board here: https://oscarliang.com/product-7tl5

Or you can try to solder the antenna to the board directly as shown here (image credit to Jeremy Fidler). The coax wire has shielding that should be soldered to ground.

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17 comments

MaD ZSK 21st June 2021 - 9:00 pm

Radiomaster has launched this mod

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Chase Philport 9th June 2021 - 7:55 pm

If the board side of the antenna connector somehow became damaged, replacing it is also an option.

I believe the part number is either a Murata MM5829 or MM4829 for the surface mount RF connector. I have soldered them by hand before and its very straightforward with a set of tweezers and a soldering iron. If someone were to replace it, just order both the 5829 and 4829 and one will probably be the right footprint.

I figure if you’re going to solder, at least do it right! Might want to add this into the article!

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Spicy 30th December 2020 - 3:14 am

If you do the removable antenna mod, it is a good idea to look into potentially buying a “terminator” or “load” cap. Basically just a brass little cap to put on it that would prevent frying the module if you accidently turned it on without an antenna. So for instance if you want to run crossfire/tracer/ghost, you could put the little terminator on there. If you happen to create a model for simming or something and accidently turn on the internal RF module, the terminator would save it from overheating.

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tim 28th November 2020 - 3:30 pm

Hi Oscar, I have just attempted this mod but backed out when I couldnt see any way of securing the SMA connector in the printed holder. I can see how it prevents the connector from being pushed down into the case, but cannot see what stops it from either rotaing, or being pulled up out of the case. I thought about gluing the coax into the holder, but that seemed too much of a bodge, so I reverted to the stock aerial. Perhaps Im missing something here, and was looking forward to fitting my diamond aerial, but ….. ??

Is there a way for me to post a picture here on my comment ?

Thanks

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Oscar 10th January 2021 - 12:09 am

there’s a zip tie holding it in place

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Alessandro 7th October 2020 - 1:30 pm

Thank you for the guide Oscar!

Actually I don’t use the internal transmitter of the TX16S at all, i only use the external crossfire module. So my question is, after having modded the antenna, is there something to plug on the SMA in order to avoid any damage on the internal TX board ? I mean something like a “fake load”, like a SMA plug. I don’t need an antenna, I just want to close the SMA connector avoiding any possible damage.

Thanks!
Bye

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Oscar 8th January 2021 - 10:17 pm

Yea it’s best to have an antenna attached when you use the TX, just in case somehow the internal TX module is activated. You can put a “dummy load” on it, these can be bought on sites like Banggood. They are small and you can just leave them on like a cap.

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Dom 29th September 2020 - 3:01 am

Hey Oscar, thanks for the guide.
I couldn’t find out the dBi of the stock antenna. Do you know how much it is?
Otherwise its hard to tell which other antenna to put to actually increase the range.
I did measure the original antenna and the efficiency is better than I expected. Around -18dB at 2.4 – 2.5 GHz .
I hope you can help
Thanks

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Christoff Helsen 17th September 2020 - 1:22 pm

Hi Oscar,
I did manage to power up the tx16 pro hall gimbal version without antenna. After, I think, 30sec to 60 sec I saw my mistake. How can I be sure that the transmitter module is still reliable? Should I replace it? Stupid me!!

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Oscar 29th September 2020 - 10:45 pm

I think it’s probably still okay. Just test the range in a safe area and see if RSSI is normal.

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oi! 12th September 2020 - 5:50 pm

You can find UFL to RP-SMA (and probably SMA) adapters with the wide base, so you don’t need an adapter for that. The non-removable antenna is a CE requirement I believe, that’s why the micro crossfire v2 unit has been designed the way it is now, with “non-removable” antenna which you ofc can replace with relative ease. I’m in the process of doing this to my radio too, I’m just waiting for the parts. The original antenna is pretty bad, even the cheapest wlan stations have at a metal pin keeping the joint together, this one is just pure plastic and breaks like glass.

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Gino 22nd August 2020 - 12:46 am

Thanks for the tute! Just got the parts I needed and am going to try this out once it arrives. :)

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mal 16th August 2020 - 7:37 pm

Hello
thanks for the very detailed procedure but does this really help the range of the radio?
thank you

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Oscar 17th August 2020 - 7:40 pm

If you use a higher gain antenna, yes

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Scott Powdrill 22nd July 2020 - 7:54 pm

Hi there Oscar, thanks for the guide. Sadly I don’t have a 3d printer so cant seem to acquire the SMA holder that you printed. Is there anywhere I could get one from? Ive been looking for a RPSMA *panel mount* to ufl /ipex but all the ones available don’t seem to be long enough.

Any ideas?

Cheers

Reply
Oscar 31st July 2020 - 3:24 pm

You can download the STL file from thingiverse (link in article), and use a local 3D printing service – you can upload the file and they will print and ship it to you. Just google 3D printing service in your local area.

Reply
Steve M. Potter 1st July 2020 - 10:30 am

Thanks, Oscar! That was so detailed and carefully documented.
Very helpful! Keep up the good work!

Reply