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.
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
- 1x 10cm (4inch) U.FL to SMA coax cable (or RP-SMA, depending on what antennas you are going to use)
- 2x 6mm-7mm screws, preferably M2.2, but M2.3 should also work. Don’t ask me why the odd screw size, ask Radiomaster :) eBay should have them
- 1x small zip tie
- Removable glue, such as hot glue or E6000 glue
- 3D printed holder (for the coax cable): https://www.thingiverse.com/thing:4493205
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.
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.
- Cheap Antenna: https://bit.ly/2NyqFU1
- VAS Diamond Antenna (RP-SMA): https://bit.ly/2B38MKf
- VAS Shapeshifter (RP-SMA, Selectable Gain): https://bit.ly/2Yp2v4t
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.