Advantages of a Highly Directional Antenna
- Parabolic highly directional antenna.parabole image by jeanphilippe delisle from Fotolia.com
Highly directional antennas are of two kinds, the grid style seen on top of television sets and the dish-shaped ones commonly used to receive satellite TV stations. A highly directional antenna offers a number of advantages over the other two types, which are omni-directional and semi-directional antennas. As its name suggests, the design of the highly directional antenna allows it to hone in on one direction more efficiently. - Grid antennas are flat with slightly curved edges. They look rather like barbecue grills with a device in a central point to collect the signals as they are relayed off a mesh of bars which make up the grid. Dish antennas are more properly known as parabolic antennas, from their inverted-bowl shape. They work by concentrating all the signals into a center point, usually a raised receiver or transmitter located a distance above the surface of the bowl, which is the point where the signal is at its strongest.
- To explain how this kind of antenna offers better reception or transmission, imagine one hand cupped around one of your ears and pointed in one direction, while the other ear is covered by the other hand. You have in effect transformed yourself into something similar to a highly directional antenna. Sounds from the direction at the open end of the cupped hand reach the ear more loudly and more clearly, while noises from the direction of the blocked ear are muted or inaudible. This is how a highly directional antenna works.
- A highly directional antenna improves the signal reception because it is pointed at the origin of the signal. Multi- and omni-directional antennas pick up all signals from all directions, resulting in too many incoming signals and a weaker signal from the direction of choice. Highly directional antennas also "ignore" signals coming from places other than the one they are directed to, which cuts down the interference with a chosen signal. Another advantage these antennas offer is the ability to change the focus of the receiver to another direction. For example, when switching channels on a TV set, the grid aerial, or antenna, is moved around to get the best reception or signal. To get the best signal from any highly directional antenna, it is recommended to mount it as high as possible on a given building. This cuts down the chances of signals being blocked by tall buildings and landscape features such as trees, hills and mountains.
Types of Highly Directional Antennas
How Highly Directional Antennas Work
Advantages of Highly Directional Antennas
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