Typically, independent repair antennas is more about the settings. Hams know the parameters that require adjustment. In particular it concerns improvised device for receiving a signal. For example, an ideal VSWR is equal to one, the descriptions in the self-assembly or antenna see a priori calculation of the parameter, or instructions on how to adjust the size and scheme using SWR. Such an approach would reduce the loss of signal to the first amplifier stage, therefore, increases the sensitivity of the receiver (the range of the transmitter). In practice things mean improvement of quality and a firm grip distance stations and radios. It is important for terrestrial antenna.
Today soldering optional step. Return the integrity of the telescopic antenna (non folded) will shrink film. Good enough to ensure good contact at the site of the fracture. To braze steel, buy a special acid stripper surface.
Adjustment of aerials
Funny sounding phrases repair collective antenna or antennas repairs himself. This passive devices that do not require professional maintenance. If a child has broken, make repairs telescopic antenna, using sidecutters or sandpaper ends, solder. Detailed instructions are not required to repair the antenna alone can any man (boy).
Regardless of the incoming signal wave is characterized by a frequency and polarization. Two aspects of the design of the antenna is determined. Making power adjustments and the incoming signal. Depending on the data it addressed the issue of strengthening required to get there due to the directional properties or amplifier stage.
It specifies that the sensitivity of the receiving device is called the minimum signal level trapped equipment. Of course, the lower the field intensity at which the broadcast program is surely tapped, the better. The sensitivity depends on the loss of signal to the first amplifier. After no longer so critical damping. For this reason, the feeder between the antenna and the receiver try to make as short as possible. To minimize SWR voiced purposes. In this case, power passes to the feeder. Known concept of harmonization, the term is closely associated with said parameter. Ideally the characteristic impedance in the circuit is equal. The antenna is made of 75 ohm cable to 75 ohm and 75-ohm receiver. If a link is knocked out of the series, matching devices are used. The quarter-wave transformers, U-loop, line segments.
How to improve the signal level. Take the trouble to properly aim the antenna. Plate should look at the moon. On the ground harder. There is a concept - re-scattered signal. Not the fact that the station will give maximum area of reliable reception. Main power can come up with an arbitrary azimuth and elevation, should suffer in the search for the right solution. People extraneous radio wonder why in the corner catches the receiver better than window in Actually just - in the window sill there is no superposition of trajectories favorable scenario fields. Simple language this means that waves are formed in an incredible way, giving an amazing picture.
Novice like unclear explain that if a given point in space two will develop strong signal in phase opposition, will vanish. Couple weak rays can give a much better effect, if the wave is coherent. If people could see radio waves, the room would be riddled with failures and vibrant places, like playing sea waves reflected on the rock. The picture is not to be permanent. Every cloud, rain, wind will affect the result. For this reason, do not always have enough time the only aim and adjust the antenna for permanent reliable reception.
Features of adjustment of satellite dishes
Satellites easier. Tricolor TV antenna targeting once and for all. The bracket is provided with several sets of bolts for the specified purposes. Suffice it to tighten as it should, in the years to ensure the correct direction. Note that the broadcast geostationary satellites. From the Earth surface appear motionless. This is possible when 24 hours in the spacecraft performs exactly round in its orbit. The above alignment get moving satellites over the equator at an altitude of 20,000 km. Exact figures are not too important, the main thing to understand that the broadcasting apparatus hanging over the equator at an altitude of a single, does not happen the same azimuth for two different satellites.
Galaxy of satellites in the sky writes arc with long-calculated form. Therefore, it becomes possible to catch the weight on the plate programs. To achieve the goal arc is placed, hung with radiators. As a result, the reflection laws each converter takes a single satellite. It is important to sustain a polarization (horizontal or vertical, there is also circular in Russian).
Many have understood what was going conversation. Inside the converter is depolarization plate. Take the trouble to put it slightly differently, to change the setting in the desired direction. For receiving a right polarization inclination is 45 degrees in the vertical direction relative to the axis of symmetry of the irradiator in the case of the left indentation being in the opposite direction. The question arises, why fuss. Here are a few answers. Some experts believe that in the Russian Federation adopted the circular polarization technology as a tribute to the Soviet Union. In the past, it was decided not to build a geostationary spy satellites. Then for linear polarized reception on the ground is difficult, at times the plane tilted at an unexpected angle. The use of circular specified complexity to decide - could only target plate on the spacecraft's trajectory.
On the plane of linear polarization inclination additionally influenced at least two factors:
- The position of the satellite in the sky. We have said that the spacecraft scattered in an arc. Satellites on the horizon are seen slightly tilted. We have to more precisely target the irradiator with respect to the plates and tilted as desired.
- The Faraday effect is known: an electromagnetic wave rotates in a constant field of the Earth. This leads to an inclination of the plane of polarization, it is difficult to calculate in advance the choice. Have experimentally twist converter, adjusting the satellite antenna.
Plates vary in diameter. Focal length is related to the opening angle of the illuminator, or receiving becomes uncertain or eliminated. Large opening in conjunction with a small plate looks silly. In theory irradiators placed in the focal plane should be. Here it intersects rays came parallel with a certain direction. To achieve a result, sell special guides, which are strung converters.
Carrying out repairs and tuning of the antenna Tricolor, it is useful to use special instruments. For example, Satellite Finder. The machine is switched between the receiver and antenna, squeaks piercingly with increasing signal level, when the master plate rotates around. At first reached the correct position of the antenna, then the turn to adjust the position of the feed element. Here will be useful knowledge, as set out in the article. Experimentally find the right slope. Job easier to do together, focusing on satellite search program built into the receiver. The process tedious and long, but productive.
Add about ranges. As with commonly used linear polarization, and Ku - linear. Already talked about the Faraday effect at high frequencies is less evident. Broadcasting Ku predominantly linear. Depolarizer converts circular polarization into linear, but a linear makes approximately similar. For correct adjustment it is important to know:
- Depolarization plate made of a dielectric.
- The thickness, length, shape affect the reception quality.
- The structure of the depolarizer includes steel pins that are visible when looking into the irradiator. Two pathogens - vertical and horizontal.
- To take on the converter both C and Ku bands, you need to buy a combined model. On fail to conduct a simple illuminator reception.
Combined converters antenna will lose part of the signal, the same occurs if the two put side by side, one for the band. There is no perfect solution, it is possible to fight:
- It takes the combined illuminator antenna without plate.
- The feeder cut one tee feeding separately two receivers (one per band) and two televisions.
- By indications art is the antenna where a maximum signal.
- Starting material selection, size and position depolarizing plate. Not the fact that the best option would be the factory, be sure to tilt the illuminator as described above.
As a result, there is a chance to find a position in which both bands show up well. This means that the repair of TV antennas ended positive.