How to choose all-wave television antenna
I'm sure many, have asked such a question. This, at first glance a simple matter, is proving to be pretty tricky. Even an experienced professional, assessing reception conditions, can not give 100% accurate conclusion what equipment should be used in the particular case.
The selection criterion of the antenna of the complex antenna and amplifier distribution the equipment is composed of many factors:
The great value has direct visibility to the telecentre and if you have the ability to place the antenna above all obstacles in the direction of reception, not even try to put the antenna near the window, hoping applying amplifier you will be able to achieve good reception.
In conditions of direct visibility of well-proven antenna type Delta N and appeared in the recent time its analogs. This is a very frequently used option, but factors such as№ 2, 3, 4, 5, 6 can negate all the advantages this antenna:
If the direction of reception, there is no obstacle but the range is more than 50 miles, how could you not raised high the antenna is very difficult to achieve the desired result. At this distance begins to affect the natural signal attenuation in the atmosphere. In this case, the assistance may come amplifier. Preferred in such cases, the mast head amplifier located near the antenna and ensure maximum efficiency.
If the direction of reception, there are high barriers to receiving point will be come direct and reflected signals with a time shift. The reflected signal will be viewed as a second, weaker image shifted relative to the base. Also, if the reflected signal has sufficient strength, view image becomes impossible due to failure of synchronization. All the trouble is in the relative simplicity of the antenna type Delta N, directivity she has a very broad and will be rebuilt from the reflected signals rarely works. In you need to apply a set of antennas with a high coefficient gain and narrow beamwidth.
Same problem as in point 3 can occur if the opposite the direction of reception are high barriers and the reflected signal, with greater the delay will be taken back. Antenna type Delta has a coefficient N protective only in UHF, the image on the meter channels will be spoiled the reflected signals. In such cases, the use of antennas with a good protective action. Or, if possible, to hide the antenna behind natural screen, for example for the Elevator booth. Of course in the direction of telecentre must remain in line of sight.
Lowlands, located between the telecentre and the point of reception is too a good source of the reflected signals. Antenna Delta N unable to deal with such disturbances, as well as in a horizontal plane in a vertical it has a very wide beamwidth. Will help only if the front part to rise above, but it significantly attenuated the useful signal. On revenue in this situation will come again complex antennas with narrow pattern orientation.
At a distance of 30 km antenna Delta N able to provide good signal to three TV sets, subject to the application of high-quality cable. When need to connect more than three TVs without power and can not do. With antenna Delta N really can feed up to 10 TVs in the application apartment amplifier type IKUSI ATB122 or mast IKUSI JMB222. When want to connect more than 10 TVs or demanding quality if you connect a TV with a large screen, it is better to apply a complex of three antennas which will allow you to level the levels ranges and the to facilitate the operation of the amplifier and get a better picture.