06-05-2014 08:41 AM - last edited on 06-05-2014 10:31 AM by /chiefAirhead/
What is an antenna? An antenna is a device attached to a transmitter. The transmitter uses the antenna to trasnmit a signal so that it reaches a receiver. Basically it focuses the energy of the transmitter.
There are 3 main types of antennas. The types are highly directional, semi directional, and omni-directional. They each have an important application and by looking at the azimuth and elevation charts you can see why each antenna is destined for indoor, outdoor, or point to point application. An azimuth chart is a 360 degree chart that displays a top down view of the propagation of the signal transmitted. The elevation chart is also a 360 degree chart and shows the perspective of standing beside and looking at the vertical propagation of the signal.
Omni-directional antenna propagate signal in all directions, similar to lighting a candle in a dark room. This type of antenna is ideal for an indoor setting. The signal is not focused in one area and can cover quite a large area. For a complete data sheet on a omnidirectional antenna look here
Omni- directional Antenna Propagation
Semi directional antennas are more focused and are used in medium or smaller distance communications. Think of a lawn sprinkler. You only want to water you lawn so you adjust you sprinkler system to only cover you lawn. This is what a semi directional antenna does, it covers a selected area. There are 3 types of semi directional antennas. Yagi, patch, and panel antenna are all semi directional antenna. For a complete data sheet on a semi directional antenna look here
Yagi Azimuth Chart
Patch Antenna Azimuth Chart
Panel Antenna Azimuth Chart
The highly directional antennas are used in long distance communications. They focus the transmission in a very accurate manner. Think of a magnifying glass / sunlight trick. The glass focuses the light in a very tight area like a highly directional antenna. There are 2 main types of highly directional antennas, parabolic dish and a grid antenna.
Grid Antenna Azimuth Chart
Parabolic Dish Azimuth Chart