What is a Radio Repeater? (Definition, Types, How It Works & More)


Written by

Rafeal Hart


Fact-checked by

Norris Howe

what is a radio repeater

Are you a radio enthusiast and are often asked, “What is a radio repeater?” It is a device added to the base station or a mode in two-way radios that extends its coverage.

It is commonly used by enthusiasts if there’s an obstruction in the line of sight of their antennas or if they want to extend the reach of their communication. As its name suggests, it repeats the radio signal from one frequency and transmits it to another.

Definition of a Radio Repeater


Are you new to the world of radios and ask, “What does a repeater do?” Familiarize yourself with its process because it’s a staple among enthusiasts and will help you be better at radio in the long run.

Repeaters are used in mobile and portable units, extending their reach for long-distance two-way radio communication with a cleaner line.

As its name suggests, the repeater repeats the signal, making it a combination of a receiver and a transmitter.

Placed in a repeater tower or other high areas, the device receives a radio signal and retransmits it to another. It’s like a bridge between two radios, letting users on both ends have a clear transmission, even at great distances.

History and Development of Radio Repeater


  • The 2 way radio repeater dates back to 1898 when Johann Mattausch publicized a radio relay communication device, though unusable. The first functional predecessor of repeaters came the following year courtesy of inventor Emile Guarini-Foresio.
  • May 27, 1899 saw Guarini-Foresio filing a patent for the radio relay repeater, which combines receiving and transmitting units in a single repeater – much like the modern ones today.

However, one weakness of his invention is the relay of the signal to an undirected antenna.

He improved his work by patenting directional reflector-type and spiral antennas, which solve the problem of message interceptions beyond a transmission line.

  • In 1901, Guarini-Foresio joined forces with Fernando Pontsele in conducting experiments to further the power of his invention.

They set up radio relay communication equipment between Brussels and Antwerp in Belgium, or a distance of over 170 miles, with repeaters placed on distances of about 16 miles from each other.

  • In December of the same year, Guarini-Foresio was triumphant when repeater-aided communication was successful between Brussels and Paris, France, with just a few seconds of delay in delivering the message.

When radio equipment improved through the years — with their ranges extended — and the development of antennas, the popularity of repeaters waned. However, the 1930s saw its resurgence, thanks to the invention of electronic lamps and the further use of high-frequency ranges.

It’s now a reliable pal in commercial establishments, government radio systems, and amateur enthusiasts.

How a Radio Repeater Works

1. Radio waves


Radio waves travel in straight lines, and Earth’s curvature affects them. They follow the planet’s curve, making it an obstruction to an antenna’s line of sight. As such, those in mountainous or hilly areas will experience poor or no reception.

Radio waves can penetrate nonconductors like concrete, bricks, and wood but not metal (and other electrical conductors like water). A repeater system works wonders for such woes.

Take, for instance, portable radios, which are low-powered. With obstruction along their line of sight, reaching the other radio is challenging. But when it transmits to a portable UHF repeater, communication is a certainty.

2. Radio repeater


With a repeater, the radio will not talk directly with each other. Instead, the repeater will be the link between the two: rebroadcasting to radio B signal sent by radio A.

Imagine if the repeater is atop a hill and the radios are at the foothill on each side. Direct communication is impossible because of the obstruction, so the transmission is coursed through the repeater channels.

Furthermore, a repeater also helps extend the range of the radio, with or without obstruction. So long as the unit is in a high position (roof, tower, top of a building), communication to the repeater will be smooth.

Types of Radio Repeaters

Ultra High Frequency (UHF) and Very High Frequency (VHF) are the common repeater frequencies, with UHF mainly used by businesses. Repeaters work straightforwardly but have different types, with digital and analog the frontrunners.

Digital Radio Repeater vs Analog


Digital repeaters are the modern siblings of the analog ones, but the latter is not inferior. New in the former is its usage of digital technology to process multiple calls with background noises filtered.

The noise-free transmission happens because the digital unit’s baseband processor converts errors into binary bits, and is corrected before being sent to the transmitter. The signal received by the radio from the repeater is corrected, too, hence the filtered noise.

Furthermore, with a series of repeaters, the signal can reach long distances — with a clear voice, at that. Only when a signal is weak that the digital repeater fails to filter the noise.

Analog repeaters, on the other hand, can only handle one call at a time and only reproduce (not clean) the signals they receive. Also, noise is a common issue. Though analog signals can be powered up with amplifiers, they also amplify the noise.

Digital repeaters deliver a better audio experience, but analog is also reliable as it can resist interference. Being a basic device, analog repeaters are cheaper (including maintenance and repair costs) and easier to install.

Here are other types of receivers and their basic function:

  • Low-power repeaters are for onsite communications, say in a campus, a tiny town, or a small compound. Its antenna is placed at a low level and only transmits two to five watts of power.
  • High-power repeaters, on the other hand, are placed in high areas, say a tower or hilltop, for wide coverage. It transmits up to 100 watts of power and enables communication across hundreds of miles.
  • Same-band repeaters operate within the same band for both input and output frequencies.
  • Cross-band repeaters, on the other hand, can link two radios with different frequency bands.
  • Vehicular repeaters, as the name suggests, are portable devices used in vehicles as signal boosters.

Components of a Radio Repeater System


The work involved in a radio repeater system is not rocket science as it’s a straightforward device composed of the following units:

  • The receiver, as its name suggests, is responsible for receiving the signal from a radio.
  • The transmitter, on the other hand, transmits the signal it produced to the other radio on the line.
  • An amplifier strengthens a signal, which is common among analog repeaters.
  • Antenna captures electromagnetic waves. Duplexers are common among base stations as it allows a single antenna to process both signal reception and transmission. For wider coverage, some users use multiple antennas for their setup.
  • The isolator is an optional but helpful component that protects the base station from signal mixing that causes interference. Some unwanted signals pass through the transmission, which an isolator helps prevent.
  • For digital units, a baseband processor is another vital component as it cleans the signals it receives.

Applications of Radio Repeaters


In businesses, it’s common to see UHF repeaters, say in a construction site or a mining area where poor signal is a challenge.

Beyond their commercial purposes, repeaters are also used in households, especially among amateur radio enthusiasts who use citizens band or CB radio repeaters. With such a device in their base station, they enjoy a stronger signal and wider reach, enabling them to contact someone from miles away.

Repeaters benefit rural communities the most, especially those in mountainous or hilly areas. With a repeater tower in rugged terrains, the community will have reliable communication, especially in times of emergency.

Pros & Cons

  • Extends coverage
  • Enhances signal
  • Filters noise (digital repeaters)
  • Cheaper compared to other network devices
  • Can be connected to various physical media
  • Can’t reduce network traffic
  • Needs a gateway or router to connect to networks of varied architectures
  • Bandwidth gets halved due to signal transfers
  • Possibility of collision domain if there’s two stations connected to the station transmit at the same time


If you want a portable radio repeater, be prepared to pay more than $3000 for the system, not to mention installation free if you employ professional service.

Setting Up a Radio Repeater


  • Step 1: Locate where to place the repeater, ideally in a high position without obstructions (hills, mountains, buildings, etc.) and away from possible sources of interference like power cables.
  • Step 2: Mount the repeater in a vertical position. You have the option to create a box or compartment for it for added security. Afterward, adjust the antenna as needed.
  • Step 3: Connect the repeater to the transmitter with an appropriate radio adaptor.
  • Step 4: Turn on the radio to test if the repeater works and troubleshoot possible issues. To test the radio coverage, two people are needed: one will stand in the antenna or repeater’s location, and the other will walk around the area of the radio coverage, testing if the transmission is successful between the radios.

The frequency range of a repeater is typically 150 megahertz to 900 MHz.

The steps mentioned above are the basic setup for those using a single antenna or a duplexer. Those working with a high-power repeater (two-antenna system) need professional help because of technical difficulties, such as preventing one antenna from taking the other’s energy.

Take note, as well, to survey the area where you plan to set up a repeater, as there might be other receivers already installed, which you can link with your radio (assuming you have permission).

The usage of amateur radio repeaters is open to anyone in its range, except for the ones used by exclusive clubs. A Federal Communications Commission (FCC) license is required for repeater operations.

It’s important to review if there are any regulations or ordinances in your area regarding repeater use.

Choosing the Right Radio Repeater


When building a repeater system, consider the type of device you need. For long-distance operations, a high-power setup is recommended, while a low-power setup is enough for short-distance two-way communication.

A choice between digital or analog repeater also depends on your usage, especially if budget is a consideration. There are many brands out there, like those from RCA Communications Systems.

Beyond the technical aspect, it’s best to consult first with anyone knowledgeable about radioing before buying a repeater.

Many radio clubs are helpful to newbie enthusiasts, and they can share best practices, life hacks, and other tips that will save you from headaches and unnecessary expenses. Plus, you can gain new friends.

Frequently Asked Questions


How do I know if I need a radio repeater?

You need a radio repeater in an area with poor reception. The device will boost your unit’s signal and extend its range. Absent the said condition, you can still use a repeater if you’re an amateur radio enthusiast.

Can I install a radio repeater myself, or do I need a professional?

You can install a repeater yourself but for complex setups, like high-power units, you might need the help of an expert. Make sure that you follow any local regulations before building your repeater.

How long do radio repeaters typically last?

Repeaters can last many years, so long as they are well-maintained and not exposed to extreme conditions. Though sturdy, you must protect them from damage, especially when placed in a low-level area.


The next time someone asks you, “What is a radio repeater?” you are now armed with the knowledge, much so that you might offer your service to build their setup.

To reiterate, a clear line of sight is important for antennas, and without so, repeaters might encounter problems, too. Whatever type you’re using, be it a low-power VHF radio repeater or a high-end digital unit, a repeater will take you beyond and beyond.

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