For the price, these remote coaxial antenna switches from China provide an easy way to switch a wideband loop array between multiple dual channel receivers.
So, I decided to build some remote coaxial antenna switches into my diversity reception system. You can find these 6:1 models online for around $30 in kit form and $40 assembled. Now made in China, various versions of these switches have been around for ten years.
Advertised specifications look pretty good. You should get 90 dB isolation at medium waves and 50 dB at higher HF frequencies. Parts look of decent quality, especially the Austrian DPDT relays. With this design, unused outputs are grounded when not activated. I thought for the price I should give these a try, so I bought two.
However, these kits do not come with coax connectors or enclosures. You will find the design requires you to mount the connectors on a top plate, and then solder the switch board to the center pin of the connectors. Although designed for SO-239 chassis mount connectors, I found that you can also get these to work with BNC connectors, which is what I wanted in the first place.
These remote coaxial antenna switches provide a seven point screw terminal for control. One pin is for your ground, which the other six accept 12 volts to switch on a relay. You also have LED indicators for the active connector. The center pin is the connection to your transceiver.
However, I wanted to use these switches to remotely connect one antenna to different radios. So, in my case, I have one antenna going to different radios, and two of these switches provide dual channel operation.
Remote Coaxial Antenna Switches – The Build Challenge
My biggest challenge is designing the top plate to mate connectors to the PCB. I could not find any sort of measurements or drilling template, anywhere. Inkscape to the rescue.
I loaded the bare circuit board picture into Inkscape. Then, I was able to measure distance and angle from the center connector to each of the six output connectors. With these measurements and a bit of trigonometry, it was easy to design a top plate in CAD. This method should work for you, whether you are planning to drill holes in an aluminum box, or 3D print a top plate.