Booster is a device used for increasing power or effectiveness. It is an enthusiastic promoter. A booster is also called as a radio frequency amplifier. It helps to maintain or increase a protective immune response. Boosters are used in all the electronic devices. They turn the performance of the device to a high position. They significantly increase the quality of reception and transmission of signals. They also extend the reception range. They are easy to install. Mainly there are two types of boosters. They are channelized and non-channelized boosters. The fixed gain boosters are non-channelized boosters. In this type of boosters the power and gain levels are set to meet specific or unusual requirements. The automatic gain adjusting boosters sets the gain over a wide rage of input signal levels. This is also a non-channelized type of booster. The channelized versions of boosters are more expensive than a non-channelized booster. These are primarily used in areas where much high level unwanted channels exist.Antenna signal booster:It is a device that is used to improve the radio communications in any area. These are usually used in an area where there are no good radio signals, which are degraded due to obstacles in the radio path. An antenna signal booster is useful in many circumstances where conventional, trunking, or paging radio signals are too weak to provide reliable communications. For example, inside buildings, stairwells, parking garages, mines, basements, subways, tunnels, inside ships, and inside factories. Antenna signal boosters are available in many of the designs.Characteristics of boosters:Boosters can be used for many reasons. Boosters are designed to provide additional signal strength. Signal boosters do no change the radio frequencies when the signal is boosted. Because of this the users do not have to switch channels on the radio. The booster provides additional channel selection capabilities in the radios. The signal boosters do not demodulate the radio signals. So there is no need of modulation adjustments. They do not alter modulation characteristics also. They have lower output power levels. Signal boosters are more compact. They use less power and require less maintenance.