Here I am sharing my experiences building an automatic 8ch USB Relay switch using an existing Ameritron RCS-8V Remote Control Coax Switch and an externally mounted 5-way switch. (others will work as on!) The point? It is to control via a PC the antenna selection allowing remote operation of the unit vs. having to use the manual antenna selector on the controller below. Below shows the finished product.

There are other ways of accomplishing this as via Audino and RaspberryPi but this is simple, cheap and fun. Plus there are a ton of online resources documenting it.


There are two parts to this project:

The unit provided by Ameritron (MFJ) is of very high quality and there is plenty of room in the case to make these modifications.

You can get detailed instructions as well as the control software by Terry, W1TR- A BIG thanks to him for getting me inspired to build this. The software download includes his current PDF, please refer to this for construction. He has done a SUPER job with writing up the procedure for the USB portion of the install. Also thanks to Nick, W7NIK who after a chat at Pacificon 2019 regarding this subject inspired me to FINALLY upload this writeup.

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Above is a closeup of the LED replacement, I have used different color LEDs as well as installed LED holders (old Radio Shack inventory from my garage) but can be purchased online as well. If you are going to do this Modification as well, you will need:

  • 5 color LEDs (Orange, Yellow, Green, etc) - Red is stock color.
  • 5 LED holders with rubber stoppers. Yes, you can go with the black plastic ones for a few cents more, but why? These look a lot nicer!

These are not included in the PDF instructions by Terry, but are very simple to do if you want to fancy up the unit like I did. remove the Circuit board (only one in the whole case) Desolder the LEDs, replace with the desired color. Pay special attention to distance as it has to fit and line-up again once replaced. So I would do one LED at the time. How do I know? I stupidly removed them all and then had to re-measure. So learn from my mistake.

Side note: I used a DYMO Label maker for the labels.

If you like the content here, you might just be interested in my new book:


Here is the finished "naked" product with the cover off. For the board modification you will need:

Please see my website article on how to properly install Anderson powerpoles on this website.


The back of the case, I had to drill a large hole for me to be able to easily connect and disconnect the USB cable which allows computer control, the stock 12vdc supplies power to the USB switching unit.

This was a temporary connection, normally you want to fish your controller cable through the white support strap on the left to reduce the pull on the screw terminals.


Overhead view of the unit as it would show from the front. Not the large hole which lines up (sort of) with the USB port at the back of the unit, make sure to position it this way.


And this is the flip or reverse view of the finished project. Now you likely understand the need to use color wires!

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This is the view of the circuit board AFTER the modifications have been done. Please note he cut trough the traces in the middle of the board. I made this with a Dremel tool. I highly recommend every ham has one! Has saved me many times and speeds up projects.


Above is the other side of the unit, the externally mounted antenna switch. I went with the 5-way version with the lightning protection even though we do not get much lightning where I live. The black mark above is leftover Coax Seal, I highly recommend using this at ALL TIMES when installing coax cables outdoors.


And for those (like me) who take everything apart, here is the exposed inside of the Ameritron 5-way switching unit.

There are many things you can do to take this project further. For me, it was fun but I ended up replacing this with a FlexRadio AntennaGenius 8x2 as this has outgrown my needs plus it integrates so well with the FlexRadio, although this does as well.

Further reading:

If you find something incorrect, have an update, or if there is something you would like to see added to the site, drop me a line here. I like to keep things as up-to-date and as accurate as possible. Thank you! - Lucas / W6AER

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