The antenna serves to radiate signals and radio wave radiation. Antenna generally divided into two by the beam, ie
Omnidirectional (all directions). This antenna radiates radio waves strong kesegala same direction.
bidirectional (both directions). This antenna radiates radio waves as strong to just two directions. The two parameters that need to be considered on an antenna is the polarization and penguatannya. Simply put, an antenna has a vertical polarization if the antenna is placed in a position perpendicular to the earth. Antenna with vertical polarization will produce radio waves with vertical polarization, too. In addition to vertical, there are also berpolarisasi horizontal antenna, the antenna plays when the field parallel to the earth.
Gambar antena FM Omnidirectional
One important factor in the FM antenna system installation is the antenna height. In the VHF band, provided that communication can take place is a LOS (Line Of Sight). So ideally communications on VHF, the antenna receiver and transmitter both have seen each other. So in between there must be no objects that can absorb radio energy.
So that radio amateurs in the VHF band is often stated that a better antenna has a small gain but higher than the antenna mounted with a large gain but low installed.