3 Steps the Complete Guide on How to Build a Radio Repeater?

Nowadays, the means of communication have become an indispensable part of life. The forms of information transmission are also increasingly diversified and developed.

A radio repeater is an integral part of this signal transmission. But, when it fails, very few people know how to fix it.

You can learn how to build a radio repeater in the following article to repair it yourself when needed with basic steps.

What is a Radio Repeater

A radio repeater is a device that can both receive and transmit a signal. The types of signals that can be shared are images & audio between two or more devices. In addition, repeaters are often located in high areas and have a large capacity to reach a wide distance range.

Today, technicians have developed many different types of radio repeaters to serve the needs of each region.

For example, businesses without special requirements will use UHF (high frequency) frequencies in large cities. On the contrary, if the location is in rough terrain, you will have to build a VHF repeater (very high frequency) to work.

Things to Prepare to Build a Radio Repeater

You will need to spend some time preparing and purchasing enough materials to start building a repeater. The following groups can be divided so that you can easily check if you have prepared enough.

  • Fixed resistor types: one with 15K ohm, one with 1K ohm, one with 2.2K ohm, two with 20K ohm, two with 4.7k ohm, and a potentiometer (1K Ohm)
  • 7 Capacitors
  • Semiconductors for signal transmission
  • Voltage regulator
  • Devices for connection and fixation
  • Breadboard/protoboard
  • Control power supply

How to Build a Radio Repeater


Radio repeaters are now installed and available in specialty stores. However, if you want to try a DIY repeater for your home, you can refer to the following instructions.

Step 1: Prepare design drawings

First, you need to determine the model of the radio repeater that you will be using. If you are not sure about what you know, you can search for sample drawings online.

Of course, there will be many different drawings to choose from, and you need to check the drawing name to be sure what type of design you are trying to build.

Step 2: Arrange and install according to the drawings

If you are a beginner, you should arrange all the necessary items in the order in the drawing before connecting them. Here are some tips for installation:

  • Use a breadboard to arrange all connections
  • Fix the power supply unit at the beginning of the whole circuit, then you need to connect power from household electricity or batteries to this point for the machine to work. Of course, the sufficient condition is to ensure the Carrier Operated Switch signal is above 0.7V.
  • Connect resistors (two of them, one with 4.7K ohm & the other with 20k ohm) to power supply.
  • To be able to generate or transmit a signal, you need to put a semiconductor low in recording mode and connect a transistor to ground.
  • Generate high power for the whole machine by installing a voltage regulator.
  • Use a potentiometer to adjust streamed audio volume.
  • You can use a 5V power supply to tune and use the radio set.
  • Use a welding machine to fix the joints together.

Step 3: Test and use

You have already completed the installation of the radio repeater in step 2. However, to ensure safety during use, you need to complete this last step. Check all connections with an electrical tester to make sure they are not open and safe.

This article focuses on simplex radio repeaters. Aside from this type, you can start trying to set up a ham radio repeater. This experiment will help you gain more experience and learn more about radio equipment.

Some Terms to Keep in Mind to Install a Radio Repeater

There will be many terms and phrases you need to familiarize yourself with before you start building a radio repeater. This complexity can be difficult and hinder you from continuing your process. So we are going to explain a few commonly used terms so that you can understand them better.


Offset is a word that indicates the state when two devices are at two different frequencies. Only then can the signal be transmitted and returned at the same time. On the contrary, if you use the same frequency for both transmitting and receiving, you will only hear yourself and cannot transmit messages to others.

Total silence

This status can be both a good signal and a sign of a disconnection.

Why is it the ideal state? Because then, the transmission is stable and strong. So, there is no interference and no noise. Usually, this happens very rarely because almost no space is airy enough to eliminate natural noise.

However, in most cases, this state represents a disconnection at a long-distance or many obstacles interfering with the signal. When this happens, you need to check your connection again and go back to the starting point until you find the frequency again.


When using radios, often there will be several stations taking part in one conversation. This complexity easily causes the transmitted signals to mix and overlap.

From there, it will cause the phenomenon of hissing, loss of voice, or even complete loss of communication because the signal cannot be connected.

Note on Choosing a Location to Install a Radio Repeater

The installation site must be in a high and open place. If installed in dense forests or around tall buildings, multiple power poles may cause interference.

Note the minimum distance between the repeater, the antenna & other objects and people (as required by the maker of the devices). If there is not enough space to ensure that, find a more suitable location. Too close a distance between the repeater and the antenna can cause danger.

Adjust the antenna height slowly and with observation.

How to Check Radio Coverage

Check transmission signal coverage by using two radios. Note that when using this method, it is necessary to adjust the specifications and frequencies of the radios to coincide.

This test requires you to build a repeater with two mobile radios and a minimum team of three people.

Accordingly, 1 person should be at the antenna’s intended location with a radio. 1 person should walk around the area where you want the radio signal to reach. These two people should send and receive messages back & forth while another person stays at the repeater’s location.


We have provided all the information we think is the most useful about radio repeaters above. We also hope you have understood the basic components of this useful device.

You can also buy ready-made items to prepare for replacement when needed. The article shows you how to build a repeater in the most straightforward and easy-to-understand way. Save and read it again when needed!

If you have any concerns as well as questions related to how to build a radio repeater, don’t forget to leave them in the comments below. Our experts will support you as soon as possible.

Thank you for reading!

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