This is a circuit board that enables you to make a 4 Port, relay controlled antenna switch, where the ports can be selected by a hand operated switch, or by a digital input.

The board includes surface mount components that handle the relay switching, indicator LEDs and DC input filtering.

The main use of this product is to provide antenna switching. But as the port to port isolation is >80dB, it can also safely be used to switch between transceivers (which is what I use it for) with an output up to 150 Watts, without risk to the input of the other radios.

I am not a big fan of the ubiquitous PL259 connectors, so the board is laid out with SMA sockets, with the intention that adapter patch cables can be used to convert to whatever type is needed. I still have two of the earlier design with BNC sockets fitted, so choose this if you prefer.

The board is fitted with a pair of PowerPole connectors for a 12V supply. You can of course make your own connection if needed.

The relays are switched using MOSFET transistors and the control lines are taken to an edge connector strip if digital control is needed. No rotary switch is included, as there are many options for how this is used and I leave that up to you. For reference, the Mouser part I used is:

• 1 x rotary switch : 611-A10403RNCQ