A satellite dish is a reflector antenna designed to receive or transmit a signal from a satellite. Satellite dishes are of various types and sizes. The most common are direct focus antennas.
What is a satellite dish?
A satellite dish is a signal transmitter (or receiver) from an artificial satellite. The principle of its operation is similar to a mirror to which the converter is attached. This device receives and converts the received high frequency signals to a lower intermediate frequency.
There are different types of satellite dishes: flat, spherical, reflective, horn, and others. Each of them has its own qualities, but due to the high price and difficulties in mass production, they are produced in limited quantities.
Types of satellite dishes
Satellite dishes are divided in shape into offset (from the word offset - "off-center") and direct focus. Focus - the place where the converter is attached.
A classic satellite dish is a direct focus antenna. The converter in such an antenna is fastened with iron spokes in the center. The spokes and converter cast a shadow on the antenna and thereby reduce the utilization of its reflective surface. And the larger the antenna diameter, the weaker this effect helps. Alas, direct focus antennas are too sensitive to any changes in the weather. Rain, snow or ice on the mirror interferes with the signal reception from the satellite.
With an offset antenna, the focus is at the bottom, not in the center. Because of this, when setting up such antennas, one must take into account the fact that here the direction to the satellite is higher than the perpendicular to the plane at a certain angle. Usually the angle of such antennas is 25-26 degrees, but there are other options. Because of this, the offset antenna is mounted in an almost vertical position, which prevents rainwater from accumulating or snow adhering.
Suspensions on which satellite dishes are mounted are of two types - polar and azimuthal. The azimuth suspension is the simplest and cheapest. An antenna with such a suspension can be tuned to only one satellite and is mounted on a bracket. To receive a signal from other satellites, you will have to carry out a complete reconfiguration of the dish.
The polarized suspension makes it possible to tune the antenna to several satellites at once. The tuning of such an antenna is more complicated, and its cost is also higher. Polar hangers are usually equipped with direct focus antennas, and offset ones - with a fixed azimuth.
Satellite dishes are made from various materials. The most popular are aluminum antennas. They do not corrode and are lighter than steel ones. But aluminum is a very soft metal and deforms easily, which greatly affects the performance of the antenna itself.
The steel plate is much stronger, but it is corrosive and heavier. Plastic antennas are quite lightweight, but they are highly susceptible to various environmental factors. Mesh antennas are resistant to wind load, but they receive less signals in the Ku-band.
