Using Repeaters – The Basics

The UK has a network of around 300 amateur radio repeaters. These are commonly on 2 metres and 70cm, although there are repeaters for other bands and modes. There is a comprehensive list of all of the UK’s repeaters at www.ukrepeater.net – Here, you’ll find some advice on setting up and using a repeater, plus some common terms.

How does a repeater work?

A repeater can receive a weak signal, or a signal from a portable user, and re-transmit it over a wider area. A repeater listens on a particular frequency, called the Input frequency. If it hears a valid signal, it will re-transmit the signal on the Output frequency. Only one person should transmit at a time, otherwise the signals will overlap.

Repeater Graphic

Accessing a Repeater

Before you can use a repeater, you will need to programme your radio with the settings for that repeater. How this is done varies with each radio, and you will need to refer to the manual, or chat to someone familiar with that radio to work out how to enter and store the settings correctly. Many find it easier to get a cable and connect the radio to a computer to use that for programming, as it’s often easier than the fiddly on-screen menu on the radio.

To access a repeater, go www.ukrepeater.net and find your local repeater, then note the following settings, and program them into your radio:

  • Output Frequency: The frequency that the repeater transmits on, and you listen on
  • The Offset: The difference between the Output and the Input frequencies (either a positive or a negative frequency). For 2m repeaters, the offset is normally 600kHz below the Output frequency. For example:
    • GB3DA, the Danbury repeater, transmits on 145.725MHz (the Output), and listens on 145.125MHz (the Input). The Offset is minus 600kHz
  • The CTCSS Tone: This is required to allow your signal to be forwarded by the repeater

You need to program your radio to switch from the Output to the Input frequency when you push the Transmit button, and to send the correct identifying tone. Only then will the repeater let you pass a message. Once you have the settings correct, save them to a memory on the radio for easy use next time.

Other Considerations

Over-deviating: Transmitting with too much audio energy / volume will result in over-deviation, and the audio ‘clipping’ and not being completely readable. When programming your radio for a 2 metre voice repeater, you would normally want to set the Bandwidth to “Narrow”, and not “Wide”, to help reduce the risk of over-deviation. It’s also important not to set the ‘mic gain’ too high, or if you have a loud voice, to talk too close to the mic, or shout.

Using a repeater

Before getting started with repeaters, it’s a good idea to have a listen to your local repeaters to see which ones are active, and what the etiquette is for using that repeater. Some things you should know:

  • Calling “CQ” on a repeater is generally not done. Instead, if you’re looking for a contact, say something like: “M6ABC listening for any calls”
  • Repeaters are primarily for mobile-to-mobile use. Many people do use repeaters at home, but you should always give priority to mobile users who need to get a call out, and leave pauses so that others can get in.
  • Joining a conversation or a net – Those looking to join in an existing conversation on a repeater will normally wait for a pause between ‘overs’ and then break into the conversation by giving their callsign. The next person to speak should bring in the station to let them send their message or join the chat. Often you will hear “break”, which is meant to be used to indicate that you have a priority message. You will often hear “station acknowledged” or “break acknowledged”, meaning that your request to talk has been heard and you will be ‘brought in’ shortly.
  • Timeout – Most repeaters have a timeout to guard against people keeping the repeater open for too long. Some repeaters have a timeout of only 90 seconds, to encourage users to keep their ‘overs’ short.
  • “K” – When someone stops talking and releases the transmit button, the repeater sends out a “K” (Morse code: ‘dah-di-dah’). This is to confirm that the repeater has reset the timeout. Try to wait for the “K” to be sent before transmitting (to make sure the timeout timer resets)

Glossary of repeater terms

  • Output Frequency: The frequency that the repeater transmits on, and that you need to tune to in order to hear what’s being transmitted
  • Input Frequency: The frequency that you need to transmit on, so that the repeater can re-transmit it
  • CTCSS: Continuous Tone  Coded Squelch System. This is a tone that you can’t hear that is transmitted with voice. Repeaters listen for CTCSS tones and will only ‘open’ the repeater if the correct CTCSS tone is sent
  • D-Star: This is a form of digital radio using the VHF and UHF amateur bands. The system is used by Icom digital radios, and there is a network of D-Star compatible repeaters in the UK. Radios are generally not cheap, and setup can be tricky, which may explain why the system is not widely used.
  • Offset: A repeater uses different transmit and receive frequencies, which are ‘offset’ by a fixed value. 2m repeaters commonly have an offset of -600kHz. For example, a repeater that transmits on 145.725MHz, will ‘listen’ for incoming signals on 145.125MHz – This is known as the Input frequency

Anything we should add to this page? Please let us know in the comments section below.

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