Understanding CB specifications.

So many different radios, which one is the best? Manufacturers and sales staff may throw a load of figures at you, but do you understand the meanings, or just get impressed by high numbers?
How much of the specification is useful for the buyer, how much is standard among all CBs, and how much is just to impress the unsuspecting customer?

Antenna impedance.
This is the same among all CB radios, 50 Ohms.

Audio power
This is not a big issue, you should be able to hear it but do not need it too loud. The impedance does not matter as long as any external speaker you use matches it.
Typical: 1.5Watts, 8 Ohms.

Adjacent channel rejection
Higher figures are better. Legal new UK CB radios must be at least 60dB, although older sets may have lower figures.

Channels
Standard system: PLL Synthesized.
Legal USA band: 40 channels, 26.965MHz - 27.405MHz.
Legal UK only band: 40 channels, 27.60125MHz - 27.99125MHz.
Legal European band: 40 channels, 26.965MHz - 27.405MHz.
Legal UK dual band: 80 channels, 26.965MHz - 27.405MHz, 27.60125MHz to 27.99125MHz.

Conversion system
Common standard: Dual conversion Superhet.

Current drain
This is not a big issue, most legal sets will be around 0.8 Amps on receive and 1.6 Amps on transmit. This figure helps to decide how large a power supply you would need to run a mobile radio at home.

Deviation
For countries where FM is used, the maximum level is set by law. CB radios must be within the limit to be allowed for sale.

Dynamic range
If quoted as a single figure, higher is better. If quoted as two figures, a larger difference between the two is better.

Emission
This is the type of modulation used, which is set by law.
FM is allowed in the UK and Europe.
AM and SSB are allowed in America.

Frequency deviation
See Deviation, above.

Frequency range
Legal USA band: 26.965MHz - 27.405MHz.
Legal UK only band: 27.60125MHz - 27.99125MHz.
Legal European band: 26.965MHz - 27.405MHz.
Legal UK dual band: 26.965MHz - 27.405MHz and 27.60125MHz to 27.99125MHz.

Frequency response
A wider range is better. Typical: 500Hz to 2.5KHz.

Frequency tolerance
A lower percentage is better. The maximum is usually set by law, and manufacturers must meet that standard to have a CB radio approved for sale.

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