Satellite dish with a twist mechanism (Description)

Satellite dish with a twist mechanism

Many fans of satellite TV do not stop taking one or two companions, but sometimes opportunities are limited and we can not afford to connect multiple antennas, especially if mounting outside the window. In such a case, you can install a motorized dish.



So what is it like to this dish? Before answering this question, I would like to talk a little bit about this unseen component of satellite television as a companion. Probably many people know that television satellites are in geostationary orbit, which is a circular orbit above the Earth's equator, being on which an artificial satellite orbits the planet with an angular velocity equal to the angular velocity of the Earth's rotation around the axis, and is constantly in over one and In the same point of the surface.

The satellites are located on the so-called polar arc at an altitude of approximately 36,900 km above sea level, the height of the satellite location is not chosen randomly, but based on the calculation of the centrifugal force to the satellite fell to the ground and flew off into space. So, rotating antenna - is a motorized antenna, designed in such a way that when moving it describes exactly the same arc as the one on which the satellites in space. Thanks to the power of gravity and centrifugal force to counter it, the satellites are stationary relative to the Earth, it suffices to set the device (motor) to move the antenna in a given position of the satellite. There are two main types of engines - the actuator and motopodves.

The actuator device, which is a motor that runs on 36 volts DC. Spinning through the worm gear, it produces a reciprocating motion back and forth, thereby causing the antenna to rotate. Actuators are mounted on a so-called polar suspension antenna. Typically, the antenna diameter is 1.2m or more. In addition to the actuator and positioner is established, with responsibilities for power and control actuator.

Motopodves - apparatus, wherein the polar suspension actuator connected to one unit. This allows them to set the azimuth antenna. But, unfortunately, there are limitations in diameter antennas. Usually motopodvesy work correctly with the antennas with a diameter of 1.3 meters. Meals motopodvesa is no longer on the positioner and the satellite receiver for television cable with DC voltage 13-18 volts.

In addition to installing the motor is also required fine-tuning the antenna and fixing satellites. There are two main stages - setting the polar axis of the antenna and tuning the exact positions of the satellites at the same time remembering them on the positioner or the receiver's menu. Polar axis starting to adjust to the zero mark. As a rule, it is the top satellite. So, once your dish, you can control it with the remote receiver has a positioner or, depending on the chosen type of engine and the model of the positioner.



I would also like to do a little emphasis on the function of Diseko (DiSEqC) positioners and satellite receivers. For convenience, a system was developed Diseko 1.2 to automatically move the antenna when changing channels from one satellite to another. The system works as follows: When you select a channel on the satellite receiver, he commands the motopodves or positioner about moving to the desired satellite. To date, all modern receivers support this function. As for the actuators, positioners that exist as a function of Diseko and hand - operated with the remote control.

As there are great possibilities of a motorized dish, but to catch all the satellites of the world it still will not be able to, as part of the satellite is on the other side of the Earth, beyond the horizon. There are some features on the reception of satellite antennas motopodvesom and actuator. In a system with a spread angle motopodvesom more motopodves can move the antenna 180 degrees. Standard actuator system allows the antenna turn about 100 degrees, depending on the parameters and the antenna manufacturer. This is usually not critical, since in most cases the Extreme satellite reception is still not possible because of the tall buildings or trees that are in the signal path.

In addition to the forces of gravity on the satellite is also the gravitational force of the moon and the sun, which causes them to shift from a given orbit. This in turn causes the drifting satellite signal reception points relative to the earth's surface. In that case, all the satellites provided fuel, allowing to adjust the trajectory of satellites and return them to the desired position. Therefore, each satellite has a certain Life as fuel reserves are exhausted. The average is 4 years, then transferred to the satellite at a lower orbit and burned in the atmosphere.

Today, one can observe the oscillation signal on some satellites during the day. This is not only dependent on the weather conditions, but probably fluctuations associated with the displacement satellite with a given axis.