An antenna booster is a device which is designed to amplify reception so that when a signal is marginal, someone is more likely to be able to utilize it. There are a number of products on the market which claim to be able to improve signal quality by acting as an antenna booster. Some of these products do indeed work as advertised, while others do not, and buyers should be wary about what they buy and how they use it.
The basic idea behind antenna boosters that work is that they expand the area of the antenna, allowing it to pick up more of a weak signal, which translates into a stronger signal for the device the antenna is attached to. Antenna boosters can be used to improve radio signals, making them popular among shortwave radio enthusiasts trying to pick up overseas broadcasts, and they were also used historically for analog television broadcasts.
The simplest form of antenna booster is simply a length of wire which increases the length of the antenna. Other techniques use reflectors, which are designed to concentrate the signal and bounce it onto the antenna so that a clearer signal comes in. Extenders and reflectors can be purchased from locations like electronics stores, and people can also make their own. Some companies also make pre-amplifiers, which attach to the antenna to amplify the signal before it enters the device.
One of the most popular applications for the antenna booster is cell phones. In areas with poor coverage, such as rural areas and buildings with thick walls which block signals, antenna boosters are used to help people avoid dropping calls. Cell phone antenna boosters are not terribly effective, because it is difficult to extend a cell phone's antenna without making the phone hard to use. What tends to be more effective is a cell phone repeater, an external advice which acts like a miniature cell tower. Repeaters are expensive, and are most commonly seen in locations like buildings and trains which want to maintain a clear signal for the benefit of occupants.
People who are interested in antenna boosters should take advantage of the reviews and tests published in places like electronics magazines. These reviews cover how the devices work, how effective they are, and whether or not a particular antenna booster is a good buy, in the opinion of the reviewer. Checking reviews before making a purchase can save people a costly mistake.