Why does channel mean so many different things in amateur radio?
You’ve probably noticed that in amateur radio, the word channel is used in different ways, sometimes in the same conversation. Depending on context, a channel can refer to:
- a name or number for a specific frequency assigned by a regulator
- a slice of the radio frequency spectrum
- the configuration settings for a digital mode like DMR
- a memory location in your radio
These different uses of the same word can be a source of confusion when you encounter them. This deep dive explains the meanings you are most likely to encounter, with examples, diagrams, and references if you want to learn more.
A channel is a name or number for a frequency
For certain radio services, like Marine VHF, Citizens Band (CB), General Mobile Radio Service (GMRS), and Multi-Use Radio Service (MURS), the FCC defines the list of frequencies on which transmissions are allowed, and gives each frequency a channel number or name. These channel identifier are often the primary method of identifying the station with which you want to communicate.
GMRS is the most straightforward example. The FCC defines 22 channels, each with a single frequency. GMRS channel 20 is always 462.675 MHz. Most GMRS radios don’t show the frequency. You choose a channel number, and can trust that all GMRS radios use the frequency the FCC defined for that channel.
Channels aren’t always referred to by number. The Multi-Use Radio Service (MURS) has 5 channels. Sometimes 154.60 MHz is called MURS 5, but sometimes it’s called Green Dot. Similar to GMRS, Any radio that let you choose the Green Dot channel will communicate with any other radio on which you can select the Green Dot channel.
| Channel | Channel name | Frequency | Maximum bandwidth |
|---|---|---|---|
| 1 | MURS 1 | 151.82 MHz | 11.25 kHz |
| 2 | MURS 2 | 151.88 MHz | 11.25 kHz |
| 3 | MURS 3 | 151.94 MHz | 11.25 kHz |
| 4 | Blue Dot | 154.57 MHz | 20.00 kHz |
| 5 | Green Dot | 154.60 MHz | 20.00 kHz |
The Marine VHF service for ship-to-ship and ship-to-shore communications used alphanumeric channel identifiers for a long time. Channel 16 meant 156.800 MHz. Channel 22A meant 157.100 MHz. Most channels are simplex, but some are duplex. Channel 27 is used for ship to shore communications: ships transmit on 157.350 MHz and receive on 161.950 MHz. Shore radios flip the transmit and receive frequencies so they can talk to ships. Two ships can’t talk to each other on channel 27. In Marine VHF, a channel can therefore mean a single frequency or it can mean two frequencies.
In 2015 the ITU, the FCC, and the United States Coast Guard got rid of the alphabetic characters in the channel names. Old channel 22A is now channel 1022. Duplex channels are scheduled to be phased out by 2030.
The NOAA Weather Radio service broadcasts weather information on seven well known frequencies between 162.400 MHz and 162.550 MHz. These frequencies are not officially assigned channel designations. However, most consumer equipment that has weather features refers to these frequences by names WX1-WX7. Because the frequencies aren’t named or numbered by the FCC, different manufacturers end up assigning different channel names to the frequencies. Some radios assign channel numbers based on when the frequencies were added to the NOAA Weather service. In this scheme WX1 is 162.550 MHz because it was the first frequency used by the service. Other brands number the frequencies in ascending frequency order, so WX1 is 162.400 MHz. In practice, this discrepancy doesn’t matter because you just scan through the weather frequencies until you find one on which you can hear the weather broadcast.
In broadcast television a channel refers to a frequency range. A television broadcast includes many different components, luminance, chromas, audio, closed caption, and more. These components require more than a single frequency to transmit simultaneously. To make it easy for consumers, the FCC defined a set of channel numbers, each of which represent a frequency range. TV channel 5 is always the frequencies between 76 MHz and 82 MHz. A TV receiver set to channel 5 knows which frequencies within that range contains the various components of the broadcast, which it reassembles into the final image and sound that is played for the user.
Sometimes you’ll hear hams say “let’s use the 2 meter calling channel”. What they mean is that we should use the frequency in the amateur 2 meter band which has been designated as the national simplex calling frequency: 146.520 MHz.
We’ve now reviewed several examples where the regulator, in this case the FCC, assigned a number or name to a specific frequency. Broadcast TV channels refer to a range, but I chose to put them in this section instead of the next section, because the frequency range has a designated channel number assigned by the FCC.
A channel is a slice of the radio frequency spectrum
Channel can refer to an unnamed, unnumbered frequency range. The range is used to describe the bandwidth or range of spectrum used by a transmitted signal.
Prior to February 2026, the 60m amateur band in the United States consisted of 5 channels. As of February 2026, the FCC modified that band to have 4 channels and a new non-channelized frequency segment. In the FCC order, they refer to four channels each with a defined frequency and bandwidth. They don’t refer to them by number, ie it doesn’t say “channel 1”. In the new segment, it defines the allowed bandwidth, but not a specific frequency, and it doesn’t refer to frequencies in the segment as channels.
In this example, a channel refers to 2.8 kHz of bandwidth centered on one of the four defined frequencies (i.e. 5332 kHz) in the 60 meter band, but it doesn’t have a number or name assigned by the FCC.
A channel also refers to the spectrum range consumed by a frequency modulation (FM) transmission. Handheld amateur radios (almost) exclusively transmit using FM, not SSB like is common on larger base station radios using lower frequencies. Handhelds support two FM modes, a wide mode and a narrow mode.
FM works by combining the message signal (your voice) with a carrier signal. When you tune your handheld radio to 146.520 MHz, the 2m national simplex calling frequency, that’s the carrier signal frequency. If you are using wide FM mode, when you speak into the microphone, the main FM signal deviates from 146.515 MHz to 146.525 MHz. Sideband energy extends that even farther. Carson’s rule gives a formula to estimate the total bandwidth used. In practice it’s approximately 16 kHz. This frequency range, centered on the carrier signal frequency, is called a channel. To avoid interference, wide FM typically uses 20 kHz of frequency spacing on the amateur 2 meter band so transmission on adjacent frequencies don’t interfere with each other.
Frequency coordination is a voluntary process that amateur radio operators use as part of “good amateur practice” (a term defined by the FCC), to avoid interference on FM repeaters and frequencies. In Utah, where I live, the Utah VHF Society coordinates the repeater and simplex frequencies used on the amateur bands in the state. Utah uses 20 KHz frequency spacing to avoid interference. The band plan says:
2 Meter FM simplex operation (even-numbered 20 kHz channels beginning at 146.420 MHz)
In the context of this band plan, a 20 kHz channel is a slice of radio spectrum centered on a given frequency. The frequencies are selected and spaced so that the approximately 16 kHz bandwith of the channel doesn’t interfere with transmissions on an adjacent channel (or slide of radio spectrum centered on another frequency).
A channel is a memory location
A channel often refers to a memory location on a radio. Each memory location stores a frequency, offset, and CTCSS/DCS tone information. Sometimes the memory location stores transmit power. Every handheld radio numbers these memory locations, and most allow you to also assign an alphanumeric name to the memory location.
These memories allow you to define all the parameters required to communicate with a particular station, save them, and then quickly recall them when you want to communicate with that station again.
You’ll hear hams say stuff like “save it in channel 135”, or “switch to channel 82”. The Salt Lake County ARES group uses channel in this way in their Standard Frequency Load. The spreadsheet has channel numbers with associated frequencies, offsets, and tones. The intent is for a ham radio operator to store these frequencies in the given memory locations. Doing so makes it much easier for an operator to switch between stations, and to coordinate moving a group of operators to communicating via a different repeater.
Handheld ham radio marketing materials often tout the number of channels a radio has. In this context, they mean the maximum number of memory locations. Here’s some examples:
Channels in digital modes
Digital modes like DSTAR and DMR have their own definitions and use of the word channel. It’s usually a memory location, but it contains different items depending on the mode. In DMR a channel is a memory location containing transmit frequency, receive frequency, color code, time slot, and talkgroup. A DSTAR channel has MYCALL, URCALL, RPT1, and RPT2.