Signal meter (S-meter)The needle swings in proportion to the strength of the incoming signal. It does so when the radio is receiving. On many radios it also shows the power going out.
CB/PA switchIn the PA position the radio works as a public address amplifier. It needs an outside speaker plugged into the back.
Noise limiter switch (ANL)ANL stands for automatic noise limiter. It cuts outside noise; its partner, the noise blanker, cuts the crackle from a vehicle's ignition.
Channel 9 switchIt jumps straight to channel 9, the channel set aside for emergencies. Many radios give the same switch a channel 19 position.
Channel displayIt shows the number of the channel the radio is on.
Channel selectorTurning it picks any one of the forty channels.
Volume knobIt is also the power switch. Turn it clockwise until it clicks to switch the radio on, then on to the listening level you want.
Squelch knobIt shuts out the background hiss when no signal is coming in. Turned too far, it lets only strong signals through.
RF gain knobIt turns down the receiver when a signal is very strong. A radio close by gives such a signal.
Microphone 4
Coiled cordThe springy cord lets the microphone reach the driver. It then pulls back out of the way.
Microphone connectorIt has several pins and plugs into a socket on the radio. Here the socket is on the front panel, and the radio is seen from above.
MicrophoneA plug-in hand microphone. It hangs on a bracket near the radio when it is not in use.
Push-to-talk button (PTT)Hold it down and talk to transmit. Let go to listen.
Back and power 5
Mounting bracketIt is screwed to the vehicle. Two thumbscrews hold the radio in it and let the radio be set at a handy angle.
Antenna connectorThe plug on the end of the antenna cable screws onto it.
External speaker jackA speaker plugs in here. The speaker inside the radio then goes quiet. The socket beside it is for a public address speaker.
Power cordIt brings power from the vehicle. The red wire is the positive one.
FuseIt sits in the power wire and protects the radio.
Antenna system 3
Coaxial cableIt carries the signal between the radio and the antenna. A pinched or worn cable spoils the signal.
SWR meterIt shows how much power a poorly matched antenna or cable returns. The antenna can then be adjusted. Some radios have one built in.
Whip antennaA common vehicle antenna is a quarter-wave whip about 9 feet tall. Shorter whips, like this one, have a coil built in, called a loading coil.
How this list was compiled: Every name checked on 2026-09-30, a name kept only where two independent sources use it. (1) Four unrelated makers' owner's manuals, read as full text on the Internet Archive: a 40-channel mobile CB with a front microphone connector, https://archive.org/details/manualsbase-id-456837 (microphone, 6-pin microphone connector, on/off volume, squelch, RF gain, channel selector, LED channel display, channel 9/normal switch, CB/PA switch, NB/ANL switch, signal strength meter, antenna connector, external speaker jack, DC power cord, mounting bracket and thumbscrews); a second maker's mobile CB, https://archive.org/details/manualsbase-id-44673 (volume control knob, squelch knob, meter, channel number display, channel selector, microphone socket, CB/PA, 9/19/NORM, ANL, NB, RF gain knob, antenna socket, EXT SP, power, fuse, PTT, whip antenna, coaxial cable); a third maker's mobile CB, https://archive.org/details/manualzilla-id-7404178 (PTT, squelch, RF gain, off/volume, mounting bracket, fuse, SWR meter); a fourth maker's mobile transceiver, https://archive.org/details/manualzilla-id-5708766 (microphone with push-to-talk switch and coiled cord, channel selector, meter, EXT SP, power cable with built-in fuse, whip antenna, coaxial cable). (2) Wikipedia, text only: Citizens band radio (noise limiter or noise blanker, PA, RF gain, NOR/9/19, SWR meter, volume control, quarter-wave whip, loading coils), Squelch, Standing wave ratio and Push-to-talk. The FCC's Citizens Band Radio Service page named in the plan refuses scripted reading. Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's radio, nothing traced. Licence: own work
How it works
The parts of a CB radio in four views: the front panel with its knobs and switches, the hand microphone, the back panel in its mounting bracket, and the antenna system on a truck.
Read the full guide
Front, microphone, back, antenna
Numbers 1 to 9 are on the front panel: the signal meter, three switches, the channel display, the channel selector and the volume, squelch and RF gain knobs. Numbers 10 to 13 are the microphone: its coiled cord and connector, and the push-to-talk button on its side. Numbers 14 to 18 are at the back: the mounting bracket, the antenna connector, the external speaker jack, the power cord and its fuse. Numbers 19 to 21 are the antenna system: coaxial cable, SWR meter and whip antenna.
Set the squelch by turning it until the hiss just stops. Turned further, it shuts out weak signals too.
Hold the push-to-talk button to transmit and let go to listen: the button switches the radio between the two.
Questions and answers
What does the squelch knob do on a CB radio?
It silences the background hiss when nobody is transmitting. Turn it until the noise just stops. A signal then has to be a little stronger than the noise to be heard, and turning further lets only strong signals through.
What is RF gain on a CB radio?
It sets how much the receiver amplifies incoming signals. Turning it down helps when a signal is very strong, for example from a radio close by, and cuts background noise.
What is an SWR meter for?
It shows how much of the radio's power is reflected back by a poorly matched antenna or cable. The antenna is adjusted until the reading is low. Some CB radios have the meter built in.
Which CB channel is for emergencies?
Channel 9. The FCC reserves it for emergencies and for helping motorists, and many radios have a switch that jumps straight to it.