4-Port Coax Relay

Introduction

The Ham Radio Workbench 4-Port Coax Relay project allows you to connect one radio to four antennas or four radios to one antenna. Two boards can be used to create sophisticated 4 to 4 switching matrix. This project gives you multiple ways to control the relays including local push button, local serial, XBee Wireless, and RS485

Connects one of four ports to a single device
Handles up to 100 watts
Can be configured to ground all ports
Low Loss on HF, 6M
PIC Microcontroller
PC Control Software
UART Pins to allow further control options
Optional RS485 Control available
Optional wireless control via XBee radios available

Documentation

Parts / Supplies

At a minimum, you will need the PCB, the PIC, and the basic BOM.

Digikey Shopping Cart for Minimum Required Bill of Materials

UPDATE 2018.06.14 - Orders placed on or before 6/14
It was brought to our attention today that incorrectly listed the relays needed to successfully build this project. The part originally included in the BOM was a SPDT single coil 12V actuated relay, but the circuit requires the dual coil version of this relay. The BOM and the Digikey parts list have been updated and the build guide will be updated tomorrow. The correct relay (QTY: 4) is https://www.digikey.com/products/en?keywords=PB963-ND

If you purchased through our online store, you will be receiving an email on this matter.

If you have purchased through our store, but have not yet placed your parts order, please doublecheck the Relay parts.

If you purchased at the 2018 Hamvention, please use the "Contact" link to connect with us if you have ordered the incorrect relays.

We sincerely apologize for the error and will work to make it right if you were affected.

UPDATE 2018.06.03 - PLEASE NOTE!
Listeners have made us aware that the Inductor used in this build is currently out of stock at Digikey. The same part is available at Newark -> www.newark.com/murata-power-solutions/13r104c/inductor-100uh-1a-radial-leaded/dp/46P8739

If you wish to build a version with full XBee wireless control and RS485 Control, please order from the following. Please note that there are multiple options for XBee radios - pick ONE for the board and another for your host PC side of the connection

Digikey Shopping Cart for Optional Bill of Materials

The PC side of the optional XBee wireless data radio link can be found at many sources including Amazon, eBay, Aliexpress and Others - search for "XBee USB adapter"The Murata 13R104C 100µH choke for the relay board is currently available at Newark (part No. 46P8739). They had about 390 in stock.

Software

This is a simple program with a graphic user interface that allows you to click buttons and send ASCII commands to the relay board. The program is written in Liberty Basic. This is a good, simple compiler that is easy to learn and has a lot of great features.