Satellite dish antennas in the shape of a dish are a type of parabolic antenna designed to receive microwaves from communications satellites. They transmit data transmissions or broadcasts for satellite television. This type of antenna is used for satellite communication and broadcast reception, space communications, radio astronomy and radar.
If you have a satellite dish mounted to the roof or the side of your house you will be able to use it as an external television antenna. This will allow you to receive digital broadcast television signals that are available in your area. You will first need to obtain an amplified clip-on antenna to attach to the dish. A dish antenna is usually operated with an unbalanced feed line.
A dish antenna consists of an active or driven, element and a passive parabolic or spherical reflector. The driven element can be a dipole antenna or a horn antenna. If a horn is used, it is aimed back at the center of the reflecting dish. The reflector has a diameter of at least several wavelengths. As the wavelength increases and the frequency decreases, the minimum required dish diameter becomes larger.
When the dipole or horn is properly positioned and aimed, incoming electromagnetic fields bounce off the reflector, and the energy converges on the driven element. If the horn or dipole is connected to a transmitter, the element emits electromagnetic waves that bounce off the reflector and propagate outward in a narrow beam. For satellite television reception, coaxial cable is used. In applications such as radar where a high-power signal is transmitted, a feed system is preferred.
