In this cell-phone age, figuring out and operating radio systems that actually take some work is a declining art. Amateur radio repeaters can be a fun project to work on by yourself or with a local radio club.
A License is Required
Before you get started, you’ll need an amateur radio license of the appropriate level. The American Radio Relay League provides study materials and actually helps administer the tests for the FCC.
What Is a Repeater?
A repeater is a device that takes an incoming signal from a mobile or handheld radio and outputs that signal from a much taller antenna and more powerful signal. Two handheld radios may only be able to communicate for a mile or less, but it’s not uncommon for a repeater system to provide a 30 mile radius (or more) where everyone can communicate with everyone else.
How to Set Up a Repeater
You’ll need a transmitter, a receiver, a duplexer, and some equipment (often digital these days) to handle such functions as performing station identification, timing out or blocking radios which may be jamming it, and the like. You’ll need an RF directional coupler or two to allow the signals to move back and forth between the two radio systems, which are operating simultaneously, usually from the same antenna array. The couplers (along with some RF chokes) prevent the RF energy from jamming or damaging the transmitter by coming back into its input.
Your antenna system needs to be very high. Typical spots include local tall buildings, hills, or other areas that command the terrain for miles around. Because amateur radio repeaters are often used in emergency preparedness, public safety agencies and broadcasters will often permit repeater antennas and equipment to be placed on their towers and grounds.
A well-run repeater becomes a sort of “watering hole” where local amateur radio operators talk to each other on their commutes. They also provide companionship for hams who are house-bound and still enjoy working with their radios.