Coaxial relay switching PCB only for two common negative latching coaxial relays

If you’ve ever built a linear amplifier for a radio with a single coax, you’ll need two coaxial relays, one on either side of the PA and this coaxial relay switching PCB will help keep things neat and tidy.

This is a PCB for latching coaxial relay switching (no parts) allowing you to switch two common negative latching coaxial relays using +12v continuous power representing TX and RX. When RX falls to 0v and TX is 12v the latching relay will be pulsed with 12 volts. Ideally, this is what a sequencer will give you. It’s primarily designed for microwave operators looking for a TX/RX relay from one antenna. This PCB is larger than the single relay switching board but functions exactly the same way. Ideally, this board would be used to switch coaxial relays on either side of an amplifier for single-output transceivers such as the IC-905 For more details including a parts list see the latching coaxial relay switching blog post.

If you need information about the relays you may check out the Ducommun Switch Catalogue.

The relay switching PCB is populated with readily available components.

Parts List

The parts for this project are readil available at you local electronics retailer.

2 x 470uF 35v electrolytic capacitors – Jaycar
2 x 1K  0.5W resistors – Jaycar
2 x 560R 0.5W resistors – Jaycar
1 x 3mm LED Red (TX)
1 x 3mm LED Green (RX)
2 x 1N4001 diodes – Jaycar
2 x 2 Way PCB Mount Screw Terminals – 5mm Pitch – Jaycar
1 x 3 Way PCB Mount Screw Terminal – 5mm Pitch – Jaycar