As you know, the CB radio is a form of voice communication system
which uses two way communications between people who are spread over a relatively small distance. This is mostly
used by the truck drivers.
The CB radio uses some very particular parts of the
electromagnetic spectrum around a frequency of 27 MHz which have been set aside for public use. It consists of 40
High Frequency (HF) channels on Amplitude Modulation (AM) and Single Side-Band.
Except for one particular channel, all other channels are open to
use completely for the general public at no cost. The power of the transmission modulates according to the
fluctuations of the pressure in the sound waves of the speech. The receiving CB radio can assess the fluctuations
in the radio wave which are accordingly converted into audio signals of the speaker.
CB Radio Amplifiers - Background
For the United States specifically, one can easily operate a CB
radio without any legal constraints, provided some rules laid down by the Federal Communications Commission (FCC)
are complied with. One such rule governs the power of the transmitted wave.
There are strict rules about this which say that the CB station
transmitter power output must not exceed the following values under any condition: Amplitude Modulation (AM) - 4
watts carrier power (CP), Single Side-Band (SSB) - 12 watts peak envelope power (PEP).
Besides this, the FCC rules also disallows the use of
the CB radio amplifier (technically, the radio frequency power amplifiers, also called a CB
radio linear amplifier, and any other device which, when can amplify the signal when used with a radio transmitter
as the source of the signal).
The only exception to this is if one has a
license in a different radio service (HAM, etc.) which allows one to use an external CB radio
amplifier.
The FCC also lays down strict rules about the
10 meter CB radio amplifier (used with the HAM radio service) for certification which ban their
operation on any frequency or frequencies between 24 MHz and 35 MHz (which corresponds to the
CB Radio operation frequency). These FCC rules basically try to keep a clean signal from a CB
radio transmitter ensuring spectral purity.
Despite these legal issues, however,
CB radio linear amplifiers are relatively accessible in the United States. CB is the
11 meter band. However, the 10 meter CB radio amplifier can be used on CBs with some minor retuning of internal
controls of the amplifier. However, generally these amps produce a lot of splatter on a lot of the CB channels. The
output can be pretty dirty and the harmonic suppression is quite poor.
Tokyo
Hy-Power makes someCB radio amplifiers,though they make the disclaimer that import of such cb radio amps into the US is strictly
illegal. However, once imported, they may work well with a HAM. RM Italy is another company dealing with CB radio
amplifier manufacturing.CB amplifiers
can sometimes be found on eBay. Expect to pay around $100, depending upon the name brand and features you’re
looking for.