Ham Radio: Using Repeaters
What is a repeater? And why use it?
The most basic form of repeater receives communication on one frequency and re-transmits at a different frequency. This is known as duplex communication.
Why is this useful?
You can greatly increase the range of your handheld or mobile radio. Repeaters are usually set up at high locations with good quality antennas and higher transmit power than your device.
Repeaters can be physically or remotely linked to other repeaters. With different kinds of links, you can reach an entire metropolitain area, or even across the world through repeater-to-repeater Internet links.
Repeaters are generally set up to operate with FM modulation on the amateur bands within the VHF (30 MHZ – 300 MHZ) and UHF frequencies (300 MHZ – 3 GHz). These are generally the frequencies used by handheld and mobile devices.
Who’s allowed to set up a repeater?
In the United States, there is one legal and one practical requirement.
Each repeater has a unique call sign and transmit frequency assigned.
How and why is access controlled?
Access to repeaters is controlled by an inaudible tone called a CTCSS or PL tone.
A repeater only repeats if it detects the tone. This prevents the receiver from constantly transmitting background noise that may be at a high enough level to trigger transmission. Constantly transmitting on a frequency is illegal, so this saves everyone a lot of grief and unnecessary power usage.
Most repeaters are configured to time out after a reasonable amount of talk time. 3 minutes is pretty common. This is to stop someone from yabbering on. Repeaters are meant to be shared.
Configuring a radio for repeater usage
Most UHF/VHF radios can be configured or pre-programmed for repeater usage.
There are three things you need to know:
The repeaters’s transmit frequency. Any time a repeater’s frequency is documented, it is invariably the frequency at which the repeater transmits. You always listen first so you know if anyone else is transmitting.
The repeater’s receive frequency offset. This could be a specific frequency, but is generally expressed as an offset. Typical values are:
VHF: – 600 KHZ. Sometimes shown as 0.6
MHz UHF: + 5 MHZ
CTCSS Tone: The CTCSS tone (also referred to as PL tone) required to enable retransmission. Sometimes shown
Modulation. This is generally FM, but can be SSB for repeaters operating in the HF range (3 to 30
MHz)
When your radio is properly configured for the repeater, it will:
(1) listen on the repeater’s transmit frequency
(2) automatically shift to the repeater’s receive frequency when you transmit
(3) automatically add the CTSS tone when you transmit.
Consult your radio documentation for how to configure it for repeater operation. On most modern radios, you can program in presets for multiple repeaters.
Linked Repeaters
Some clubs have multiple repeaters linked together. Whatever is transmitted to one repeater is sent out from all the other repeaters. The repeaters are usually linked by radio using directional antennas, but other connection types like Internet are possible. For emergency preparedness and disaster planning purposes, radio links are preferred.
On the Linked Repeaters page, there is information regarding local linked repeater systems.
They also list different “Net” times where groups meet on the repeater for different purposes.
Finding repeaters in your area
A simple google search where you specify your geographic area with will usually turn up several options.
Web site Repeater Book is a great example where you can search for repeaters around the world. It’s well documented, and if you click on the frequency link for a repeater, it will list information like:
Repeater status
Repeater basic protocol and manners
Avoid radio jargon and code words. Proper etiquette for repeaters is to not use Q codes (or even worse, 10-codes) or other jargon.
Identify yourself as required by ham radio rules – at start at end of the conversation, and at least every 30 minutes in between.
Remember that your communication may be going a long way and *everyone* can hear you. If repeaters are linked, you could be covering
Don’t be afraid to identify yourself as a beginner. Ham operators are generally very courteous and love to help.
In the examples below, we use:
callsign VA3NUB (newbie!). You should use your own.
frequency 123.456. Identify the frequency and/or call sign of the repeater before you start. It’s good to know and to inject into your intro because in the case of linked repeaters, it identifies which one you are on.
Verify that you are allowed on the frequency. If you have a Basic license (in Canada), you are not allowed to transmit below 30
MHz or to use a repeater or set of linked repeaters that transmit below 29.5
MHz. The exception to 29.5
MHz for repeaters is because you may be listening at 30
MHz (or just above), and the standard frequency offset for repeaters in the VHF 2m band is -600 KHz.
Keep it short. Don’t blabber on. Give other people a chance to join in or respond.
Don’t kerchunk the repeater. Many repeaters will transmit a beep when you finish transmitting. Some users will hit the transmit button as a test just to hear the beep. That’s called kerchunking, and it’s bad behaviour. Always state your call sign, with something like “VA3NUB testing”
-
A simple repeater session
Listen to see if anyone is else is talking. There may be a net or other conversations already happening.
Start with
If nothing back, wait 10 seconds and repeat step 2
If someone answers, acknowledge it.
If you didn’t hear their call sign, ask them to repeat
When you hear their call sign, acknowledge it
Simple conversation starters:
I’m testing my radio and repeater connection. How are you receiving me?
I’m new to this. I would appreciate any feedback on my radio usage.
I’m located in Thornhill. What’s your location? (Note: ham operators will use QTH for location. Be polite, but try to avoid jargon/Qcodes)
What equipment are you using?
Closing up the conversation.
This page was adapted from External Link