How is antenna gain (dBi) measured and used?
The unit of antenna gain is dBi. dbI means “Isotropic”, a perfect POINT SOURCE, which radiates in a spherical manner. A perfect dipole radiates with a donut pattern, broadside to the long dimension of the dipole. It is a relative measurement to an ideal dipole that radiates in a perfect sphere. To achieve higher gains, antennas are constructed such that they radiate more in one direction than another. An omni directional antenna radiates uniformly in the horizontal plane and radiates very little up or down. Panel, sector, yagi, and parabolic grid antennas radiate in cones of various widths. The higher the gain, the smaller the horizontal and vertical angles. Jerm gave the sprinkler head analogy: for a given amount of water, the distance the water shoots can be increased by focusing the spray; for a given amount of of microwave energy, distance can be increased by focusing the beam. Antennas angles are specified by their half power point (3 dbi less than the specified max output).
The unit of antenna gain is dBi. dbI means “Isotropic”, a perfect POINT SOURCE, which radiates in a spherical manner. A perfect dipole radiates with a donut pattern, broadside to the long dimension of the dipole. It is a relative measurement to an ideal dipole that radiates in a perfect sphere. To achieve higher gains, antennas are constructed such that they radiate more in one direction than another. An omni directional antenna radiates uniformly in the horizontal plane and radiates very little up or down. Panel, sector, yagi, and parabolic grid antennas radiate in cones of various widths. The higher the gain, the smaller the horizontal and vertical angles. Jerm gave the sprinkler head analogy: for a given amount of water, the distance the water shoots can be increased by focusing the spray; for a given amount of of microwave energy, distance can be increased by focusing the beam. Antennas angles are specified by their half power point (3 dbi less than the specified max output). For e
