Section 6.5: Repeater Operation #

A repeater is a station that listens on one frequency and rebroadcasts what it hears on another, usually from a high vantage point. Repeaters extend your range far beyond what your handheld or mobile rig could do alone, which makes them one of the most useful tools available to a Technician.

What’s a Repeater? #

Key Information: A repeater station simultaneously retransmits the signal of another amateur station on a different channel or channels.

Illustration showing two operators on either side of a mountain talking via a repeater on the mountaintop

Think of a radio relay station perched high up on a hill or tall building. It listens on one frequency and simultaneously retransmits what it hears on another. This extends your range way beyond what your little handheld or mobile rig could do on its own.

Now, only one signal can usefully exist on a given frequency at once, so the repeater can’t talk on the same frequency you are talking on. Instead, when you transmit to a repeater, you’re actually sending on one frequency (the input), and listening on another (the output). Don’t worry, your radio will handle this automatically if you’ve set it up correctly.

Repeater Offsets #

Key Information: Repeater offset is the difference between a repeater’s transmit and receive frequencies. Common offsets are plus or minus 600 kHz on 2 meters and plus or minus 5 MHz on 70 cm.

When using repeaters, you need to know about offsets. An offset is the difference between a repeater’s transmit and receive frequencies. Your radio needs to be set to the correct offset to communicate through a repeater effectively.

Here’s a handy table of common repeater offsets for various amateur radio bands:

Band	Frequency Range	Common Offset
6m	50–54 MHz	-500 kHz or -1 MHz
2m	144–148 MHz	±600 kHz
1.25m	222–225 MHz	-1.6 MHz
70cm	420–450 MHz	±5 MHz
33cm	902–928 MHz	-12 MHz or -25 MHz
23cm	1240–1300 MHz	-12 MHz or -20 MHz

Remember, these are the most common offsets, but there can be exceptions:

On 2 meters, repeaters above 147 MHz typically use a positive offset, while those below use a negative offset.
Some areas might use non-standard offsets due to local frequency coordination.
Certain repeaters, especially those on less common bands, might use split frequencies that don’t follow these standard offsets.

Many modern radios can automatically set the correct offset based on the frequency you input, but it’s always good to double-check. When in doubt, consult a local repeater directory or ask a fellow ham in your area.

The Reverse Function #

Key Information: The reverse function on a VHF/UHF transceiver lets you listen on a repeater’s input frequency.

When you’re using a repeater normally, you listen on its output frequency. The reverse function temporarily swaps your transmit and receive frequencies so you’re listening on the input frequency instead — i.e., listening directly to whoever is transmitting to the repeater. This is useful for determining whether you can hear the other station directly without the repeater (which means you could potentially talk to them simplex), or for troubleshooting whether a repeater is working properly. In some cases it may also let you talk to the other station without the repeater, though this should only be done with care to avoid interfering with the repeater.

Accessing Repeaters #

Key Information: Most repeaters use CTCSS tones or DCS codes for access. CTCSS (Continuous Tone-Coded Squelch System) is a sub-audible tone transmitted along with normal voice audio to open the squelch of a receiver. Difficulties accessing a repeater could be caused by improper offset, wrong CTCSS tone, or wrong DCS code.

Many repeaters require either a CTCSS (Continuous Tone-Coded Squelch System) tone, often called a PL (Private Line) tone, or a DCS (Digital Coded Squelch) code to access them. CTCSS is a sub-audible (low frequency) tone transmitted along with normal voice audio to open the squelch of a receiver. DCS, on the other hand, is a continuous stream of low-speed digital data.

Both serve the same purpose: they help prevent interference and unintended activations of the repeater. Your radio must be set to transmit the correct CTCSS tone or DCS code for the repeater to even recognize your signal. Check your local repeater directory or club information to find out which system a particular repeater uses.

You’ll also encounter DTMF in repeater operation. As we discussed in Section 6.4, DTMF uses two simultaneous audio tones — the same technology used in touch-tone phones. Unlike CTCSS or DCS, DTMF is not used for basic repeater access but instead for controlling repeater functions, activating links to other systems, or accessing internet-connected systems like IRLP (which we’ll discuss later in this section).

If you’re having trouble accessing a repeater whose output you can hear, there could be several reasons:

You’re using the wrong offset.
You’re either missing or using the wrong CTCSS tone or wrong DCS code.
You’re too far away or in a poor location for your signal to reach the repeater.
Your radio lacks the power to reach the repeater.

Always double-check all settings when programming a new repeater into your radio.

How Repeater Conversations Work #

Key Information: When calling another station on a repeater, say the station’s callsign, then identify with your callsign.

Here’s how a typical repeater conversation flows:

You transmit on the input frequency (your radio adds the correct offset and tone).
The repeater picks up your signal and retransmits it on the output frequency.
Other hams in the area hear you on the repeater’s output frequency.
When they respond, they transmit on the input frequency, and the repeater retransmits their signal on the output frequency, completing the communication cycle.

Calling someone on a repeater is simple: just say the callsign of the station you want to talk to, then identify with your callsign. For example: “W1ABC, this is K2XYZ.” This is more of a convention than a rule, but it’s an appropriate way to get someone’s attention on a repeater.

Repeater Etiquette #

Repeater etiquette is important since these are shared resources:

Listen before you transmit to avoid interrupting ongoing conversations.
Keep transmissions reasonably short and leave pauses for others to join.
Identify yourself using your callsign as required by FCC rules.
If you want to join an ongoing conversation, wait for a pause and say your callsign.

Like any equipment, the owner of the repeater gets to set the rules for its use (subject to FCC regulations). Keep in mind that each repeater may be a bit different in the conventions that people follow.

Calling on a Repeater #

Key Information: To indicate you’re listening on a repeater and looking for a contact, use your callsign followed by the word “listening.”

Generally speaking we don’t actually call “CQ” on a repeater — there isn’t any reason we couldn’t, but it is generally frowned upon with varying levels of intensity by different members of the community. Instead, to indicate that you’re listening on a repeater and looking for a contact, use your callsign followed by the word “listening.” For example: “K2XYZ listening.”

Here are some other common phrases:

“This is KD7BBC, mobile and monitoring” — indicating both that you are moving around and that you are on the frequency, presumably happy to talk to someone if they want.
“K1BEN listening” — shorter version of the same.
“This is AC7DM. Anyone around to chat while I drive?” — more casual, but still fine.
“This is NV7V, could I get a signal report?” — indicates that you aren’t looking for a QSO, just to confirm how well you are getting into the repeater.

The specifics don’t matter, as long as it’s easy to understand and not deceptive.

Repeater vs. Direct Communication #

When communicating through a repeater, you’re using two different frequencies: the repeater’s input and output. This is different from direct station-to-station communication on a single frequency.

Key Information: Simplex describes an amateur station that is transmitting and receiving on the same frequency.

Sometimes, designated frequencies are specifically set aside for simplex contacts so that hams who can reach each other directly aren’t tying up a repeater unnecessarily. We’ll cover simplex operation and these designated frequencies more thoroughly later in the book.

Linked Repeater Systems #

Key Information: A linked repeater network is one in which signals received by one repeater are transmitted by all the repeaters in the network.

Earlier we thought about a single radio relay station located in a high place and discussed how helpful that could be. Just think, though, of what we could do with a network of radio stations set up on different hilltops across a wide region! In a traditional setup, each repeater would serve only its local area. But in a linked repeater network, signals received by one repeater are transmitted by all the repeaters in the network.

It’s like having a group text message — when one person sends a message, everyone in the group receives it regardless of their location. Similarly, when you transmit to one repeater in a linked network, your transmission gets relayed through the entire network of connected repeaters, greatly extending your communication range.

Linked repeaters are particularly valuable for:

Emergency communications across wide areas.
Club nets that span multiple cities or counties.
Special events where coordination is needed across a large region.
Allowing mobile operators to stay connected while traveling long distances.

Internet-Linked Repeaters and VoIP Systems #

Key Information: Voice over Internet Protocol (VoIP) is a method of delivering voice communications over the internet using digital techniques.

Some repeaters aren’t just linked through traditional radio connections — they use the internet to connect with other repeaters across vast distances. This is done using Voice Over Internet Protocol (VoIP).

Key Information: An amateur radio station that connects other amateur stations to the internet is called a gateway.

Gateway stations are the bridges between the radio world and the internet, enabling global communication.

Two popular VoIP systems mentioned in the question pool are IRLP and EchoLink:

IRLP (Internet Radio Linking Project)

Key Information:
The Internet Radio Linking Project (IRLP) is a technique to connect amateur radio systems, such as repeaters, via the internet.
Over-the-air access to IRLP nodes is accomplished by using DTMF signals.

You’ll enter codes using your radio’s keypad to connect to various IRLP nodes around the world.

EchoLink

Key Information:
EchoLink is a protocol that enables an amateur station to transmit through a repeater without using a radio to initiate the transmission.
Before using the EchoLink system, you must register your callsign and provide proof of license.

You can use software on your computer or smartphone to connect directly to the system. The license-verification step ensures only licensed amateurs can access it.

A working knowledge of repeaters covers most of what a Technician needs to get on the air. The next section moves from operating to maintaining: basic repair, testing, and the tools that help you figure out what’s wrong when something stops working.