I am moving a large part of my shack to a wall mounted radio switching board. My goal is complete remote relay switching of antennas for my diversity receivers and loop array.

Last month, I described my idea for switching antennas between multiple diversity receivers using Arduino relay modules. Since then, I have been busy and built this homebrew radio switching board on the workbench.

Currently, I am writing the firmware and control software. And testing all the connections as I go. I will describe the overall system and individual modules in future articles.

Rather than build this directly on my operating desk, I am using a wall mount approach, shown above top. I started out with a sheet of ½ inch plywood, approximately 40″ by 18″. It’s painted grey for aesthetics. I 3D printed some plastic clamps to mount the homebrew radio switching board to the wall just behind my operating desk.

Shown below is the mostly completed hardware set-up laid out on my workbench. On the right, you can see my active antenna control box, power supply and distribution bus. In the center is the Arduino microcontroller and relay antenna switcher. And, to the left are three receivers – RSPduo, Afedri AFE822x and Perseus. On the left edge is an 8.1  VDC regulator to power the Afedri.

My wall mounted position, while out of the way, is close enough for USB, Ethernet and antenna connections. The whole board will be powered by a 12 VDC linear supply.

Radio Switching Board 3D Printed Structures

In addition to the wall mounts, I 3D printed enclosures for the antenna relay switcher and active antenna control box, also with relay controls. I used plastic to make clamps to hold the receivers, as well as cable clamps.

The power bus and voltage regulators are also mounted in place with printed structures. Everything is held down using small wood screws.

I found the hardest part of the wiring involved routing 22 digital and voltage pins from the Arduino to three relay modules. This was accomplished using some old 8-wire CAT cables, crimped onto DuPont connectors. That was tedious work.