Some tips about CB radios:

Originally, there were only 23 (USA) channels, and older CB transceivers used individual crystals to control the frequency of the oscillator circuits. Later on, 40 channels were introduced. Some older radios only had a handful of frequencies available by a selector switch, because crystals were a bit costly. Two crystals were required for each "channel," one crystal was needed to control the transmit frequency, another the receive frequency. Later developments allowed "crystal mixers" to achieve all the channels with fewer crystals. Eventually, Phase Locked Loops were created on integrated circuits. These devices were very stable reference points in circuitry, thereby allowing manufacturers to bypass the use of crystals.

Single Sideband is a bit difficult to describe without graphics, but if you have seen a sine wave on an oscilloscope, or a heart monitor, we can use that image to elaborate on. A traditional Amplitude Modulation signal, or AM, has actullay three waves that are transmitted. The central "carrier" signal, and two "sidebands"; upper and lower. Each of these signals requires power from the transmitter. Amateur radio operators experimented with suppressing parts of the signal, and eventually Single Sideband (SSB) was developed. A SSB signal focuses most of the power into one of the sidebands, leaving out the carrier and the other sideband, giving better range and less bandwidth to interefere with adacent "channels". SSB radios have a selector switch marked AM/USB/LSB. These were somtimes advertised as radios with 120 channels, although that is not entirely accurate. If a conversation is alrteady happening via AM transmission, the sidebands are occupied, so they could not necessarily be used by two other parties with SSB radios.

Never try to transmit without an antenna attached, especially with vintage radios. This can damage parts in the transmitter that will then need replaced. It doesn't take much to do this, merely pushing the microphone button repeatedly, or for a few seconds at a time can damage some transmitters.

There are Three basic types of radios: Base Station , Mobile, Portable or commonly referred to as "Walkie-Talkies". A Base, or Base Station has a built-in power supply that runs on 120vac, and is meant to be operated from a fixed location. These sometimes have more features and better sound quality. Sometimes these units can be used with 12vdc as well, it depends on the specific unit.

A mobile unit is what most people are accustomed to, that which is found in a car or truck. Normally very compact and runs only on 12vdc. Sometimes these are erroneously referred to as a Base on ebay listings, I don't know why. They are not.

Portable CBs are now available several different ways, 27mhz portables were offered in a low powered version, with only 1/10 of a watt transmitter power, and unlicensed. Most people had some of these when they were children. They are also available with  a full 4 watt transmit power.In the USA, eventually CB licenses were dipensed with altogether.
 Yet another variety is VHF Family Radio Service. The FRS operate at a different frequency than old fashioned CB radios. The new FRS is 49mhz  band, which does not suffer from some of the difficulties of the 27mhz band. 27mhz is particularly affected by the eleven year sunspot cycles which create interference.