The term "CB" in "CB radio&" stands for "citizens band" radio. The usable radio frequency spectrum is limited. In order to prevent broadcasters from stepping on one another, the Federal Communications Commission divides the available radio frequency broadcast spectrum between commercial radio and media, military, civil authorities like police and fire, aviation and private citizens use. Generally, broadcasters cannot broadcast outside of their allotted frequency without a license from the FCC.
Traditionally, citizens band radio frequencies are shared by multiple users. Anyone within broadcast range who has a two-way radio can broadcast and transmit over the CB radio frequency spectrum.
For Americans, CB radio enthusiasts are generally restricted to certain frequencies. Most 2-way radios come with channel selectors, however, that prevent users from intruding on forbidden frequencies. In the United States, the unofficial "trucker's channel" is channel 19, which is preset to 27.185 MHz on standard sets.
Users on Channel 19 broadcasting on some higher-end radios should avoid switching to high or band D, because that would put them in "ham radio bands&" that are limited to morse code communication. Ham radio operators frequently report voice operators intruding into the morse areas to the FCC. Truck companies can be subject to fines due to truckers broadcasting illegally. Some truckers have lost their jobs as a result of broadcasting over forbidden frequencies.
Two-Way vs. One-Way Radios
The standard car radio, household radio, or stereo system is a one-way system. It can only receive, and cannot transmit. This allows the user to listen to radio stations and any other entities broadcasting over an accessible frequency. For full citizens band functionality, the CB radio operator will need a two-way radio.. That is, the radio needs both a receiver and a transmitter. The FCC limits the transmission power of all CB radios to 4 watts. This means that no matter how much money spent, it is not legal to buy a CB radio.
CB Radio Features
When looking into what types of CB's to purchase, it is important to make sure that one is familiar with the different features. When the proper research is done ahead of time, the best informed purchase can be made.
Squelch control is a standard feature on modern citizens band radios of all types. Without squelch control, the user would hear a constant "white noise" of static over the frequency. Squelch control eliminates this static by shutting off speakers unless a signal comes in over a certain threshold.
Automatic Noise Limiting
This feature helps filter out background noise from incoming transmissions, making it much easier to understand those transmitting from noisy environments, such as the cab of a truck. Noise limiting eliminates such background noises as road noise, engine noise, rain, and other distractors.
Some radio sets allow users to switch easily between two or more preset channels, typically the truckers' channel and the emergency channel, which is channel 9 in the United States.
The National Oceanic and Atmospheric Administration does regular nationwide broadcasts of important meteorological information. Some CBs feature a switch that enables users to instantly go back and forth from NOAA weather broadcast stations.
Backlit or Nightwatch Displays
Some CB sets include special displays for low-visibility conditions. A set consisting only of unlit dials would be impractical for a driver who drives extensively at night, for example. Backlighting allows for easy operation in low-light or limited visibility conditions.
Some sets can be converted to public address functionality, allowing the user to speak into the microphone and have his or her voice come through a loud set of speakers. This is a common feature in police radio sets. PA applications require a separate PA "horn" speaker, which is not normally included in standard setups.
RF Gain allows the user to "prioritise" competing signals on any given channel. RF Gain filters out weaker signals, favouring stronger signals. This helps to eliminate competing traffic from more distant stations.
Types of Antennas
The antenna assembly is a key factor in the user's ability to transmit and receive CB radio traffic.They should be installed so that the coil portion of the antenna is above the roof of the vehicle. Otherwise the vehicle acts as a shield, impeding transmission. Size does matter: The longer the whip the better the signal.
CB Radio Antennas
CB radio antennas typically have a coil. There are three basic types of antennae, based on the wire and position of the coil. Each type has advantages and disadvantages. One of the ways we measure antenna effectiveness is by measuring efficiency. Efficiency refers to the percentage of electrical energy that the antenna converts to signal, rather than to heat. Inefficient antennas build up excessive heat, and lack range and clarity. The most efficient antenna commonly sold on the CB market is the 102 inch whip. However, few mobile applications can accommodate an antenna that large.
Base-loaded antennas typically have a higher maximum wattage than other varieties of antennas. They are relatively easy to install. However, they are also inefficient. The antenna coil should be placed at the very highest point of the vehicle for best performance. Otherwise the vehicle itself tends to shield transmissions and reception from certain directions.
Centre-loaded antennas feature antennas with a coil well above the base, though in practice not necessarily in the centre. They are more efficient than base-loaded antennas. They are less efficient than top-loaded antennas.
Top-loaded antennas are usually made of fibreglass. They feature a thin wire that is wrapped in protective layer. These antennas are generally very affordable and work better than the others.
No-Ground Plane (NGP) Antennas
Antennas need to be grounded to work properly. But not all applications provide a ready-made ground for the antenna. Installations on boats and other settings without a metal chassis to provide access to ground require a special type of antenna called a no-ground plane (NGP). These antennas have a ground built in to the coax cable.
Mounts fasten the antenna to the vehicle or structure. Their design and composition is straightforward. However, larger antennae require more substantial mounts, especially on moving vehicles. Note also that larger antennae may require occasional disassembly. For example, if the driver is going through a parking garage or some drive through food establishments, he has to quickly disassemble the antennae and remove it from the mount, so as not to damage the antenna assembly.
Vehicle chassis can affect CB radio transmission.. The ideal place to put an antenna mount is as close to the centre of the vehicle as possible. That way, the vehicle has a fairly uniform effect on transmission. Otherwise, the transmission mechanism could have "blind spots," and be unable to transmit to receivers in that direction, or have limited range in certain directions.
One way to combat this phenomenon is to use "co-phased" antennas. This involves buying and installing two antennas, one on either side of the vehicle. Each antenna there complements the other and the two fill in their generally circular pattern with little variation.
How to Buy a CB Radio on eBay
Buying CB Radios on eBay is easy. Log on to eBay and enter the specifications you desire into the search box. From there, you can click on any listed item to find more information about its features and benefits. Pay careful attention to accessories. Some CB radio transmitter sets come with all the basic accessories you need to get started on CB radio. Others require additional investments for such things as CB radio microphones, speakers, CB radio antennas and CB radio mounts. Under the eBay system, you can bid what you think is a fair price for any item listed, if the seller authorises auction bidding. Some sellers have one established price. This is particularly true for newer items
eBay users can leave "feedback" on sellers, so you can see what other buyers' experiences have been. Shipping on eBay is often free. The Top-Rated Sellers get a special "badge" visible on the equipment listing that you get after you enter in your search term in the search window.
With the amount of different CB radio's on the market, it can be quite daunting as to what to buy. In most cases your budget determine what you can afford. Citizens band radio has evolved from its glory days as a hobby in the 1960s and 1970s. But CB radio still has a great deal of utility in commercial uses, especially where cell phones just aren't practical, and where a number of individuals must be able to communicate instantly. A CB radio network allows a dispatcher, for example, to put out a net call to dozens and even hundreds of drivers on the road, subject to the range limitations of the radio. A cell phone would be impractical for calling so many people at once.
Citizens band radios are the communications medium of choice for affordable short-to-medium range simultaneous multi-station transmission where the security of the transmission is not a concern. Obviously, unencrypted citizens band radio transmissions can be picked up by anyone in a receiver, so you do not want to broadcast sensitive or confidential information over citizens band frequencies.