Advice 1: How to calculate length of antenna

The quality of the radio when receiving and when transmitting to a very large extent depends on the antenna. Antennas come in different types. They can be directed and undirected, can have different polarization. But all antennas have common elements. This projecting part and the lower, that is what it is connected to the device. They need to be calculated.
How to calculate length of antenna
You will need
  • - parameters of the device to which you will connect the antenna;
  • calculator.
Instruction
1
Determine the type of antennathat you will be doing. It can be symmetrical or in the form of a beam. The signal to different antenna types are served in different ways. If the antenna circuit of the receiver or transmitter has an inductive connection with the circuit, it is advisable to apply the scheme of the symmetrical power supply using two-wire line up to 200 to 700 Ohms. For the crystal radio, input devices with earthed grid or base and also for transmitters with output of P-loop, is more suitable antenna type Luch with one-wire line.
2
The most common type of antenna is symmetrical vibrator. It is a wire whose length is equal to half the wavelength of the emitted signal, and the length of each shoulder respectively equal to the quarter wave. For a device operating in the VHF range, these elements made in the form of tubes or rods.
4
Signal to the antenna of type "beam". From one end of the wire back a distance equal 0,171 wavelength. In this place to the antenna connect odnoprovodnoi line which should be perpendicular to the wire-vibrator at a distance of 0.15 wavelengths. Then odnoprovodnoi line can be curved in any direction.
5
A symmetrical antenna connected otherwise. The total length of the vibrator remains the same. Find the center of the wire. Mark this point. Measure a segment with a length of 0.13 wavelength so that its end points are symmetrical to the middle. One of those points, solder wires, which are at a distance of 0.15 of the wavelength of wire from the vibrator is soldered to the power cable, made in the form of a two-wire line. This line connects to the radio.
6
Both antennas have approximately the same parameters. Select a particular connection type, on the basis of consent of the antennam of the contour of the receiving and transmitting equipment.
Note
Antenna mounting is performed on the dielectric insulators. They usually make them porcelain, glass or plastic. The calculation and the measurement antenna should be considered in all, mounted on insulators.

Half wave vibrator can be suspended both horizontally and vertically.
Useful advice
Kind of a half-wave vibrator can be vertical (the so-called whip) antenna. It is powered by a coaxial cable impedance of 50-75 Ohms. In this case, the metal core of the cable is connected with the end of a half-wave vibrator (pin), and the braided cable is earthed, or it turns out to counterbalance. It may be the iron roof of the building or antenna mast, made of metal pipe.

Advice 2: How to increase antenna reception

The quality of television and radio signal does not always satisfy the viewers and listeners. Moreover, interference can be the case even when there seems to be a bigger antenna. In order to improve the quality of reception, the antenna should be configured correctly.
The sensitivity of the antenna largely depends on the effective height
You will need
  • coaxial cable, portable radios or mobile phones.
Instruction
1
Effective height of the antenna is one of the most important parameters that determine its sensitivity. Therefore, to improve reception , raise the antenna as high as possible above the ground, regardless of whether it is on radio or television.
2
If the antenna is aimed, try to reinstall it so that between it and the signal source there is no interference. Such obstacles can be tall buildings or other structures, power lines and so on. You can try to fine-tune the direction to the source signal. You can use the assistance of an observer, a control signal at the receiver. For communication it is possible to use a portable radio or mobile phone.
3
If you have a directional antenna with a flat polarization (type "Wave channel" and the like), check the polarization of the received signal. Configure it according to the data obtained. For this you need to rotate the antenna about an axis aimed at the signal source. Often simply try to rotate your antenna by 90°.
4
The efficiency of the antenna can be improved by the antenna amplifier. But in this case, the gain limit is set by the noise level. To reduce their level use shielded reduced, that is, the antenna is best to connect using coaxial cable.
5
The efficiency of the antenna, especially when receiving long, medium and short wavelengths can be improved by installing additional ground. It should also be borne in mind that the antenna must be matched in impedance to the input circuit of the radio. That is, it is necessary to connect the type and brand of cable recommended in the instructions to the receiver or TV.
Note
Antenna long, medium and short waves can be a piece of wire lengths. The suspension point of such antennas is also recommended, based on the highest volume receiving the desired stations. It is necessary to change the position of the antenna.
Useful advice
If we are talking about indoor antenna, the best solution is to install a fixed external antenna. This will dramatically improve the quality of reception. Are also external antenna it is recommended to connect the portable mobile radios and televisions during their operation at steady-state conditions.

Advice 3: How to connect the aerial cable

Aerial cable is suitable for connecting an outdoor antenna to the access point located indoors. The antenna cable can improve the quality of the received signal. To connect the antenna cable it is recommended to use a special adapter.
How to connect the aerial cable
Instruction
1
The antenna cable is badly bent, so proper installation requires a flexible adapter. In the commercially available connectors for the antenna cable with a diameter of 6 mm thick Central core.
2
For mounting the connector, do not need soldering equipment. Remove the top insulation to a length of about 20 mm. Trim the top layer of insulation around the circumference. Try not to damage the metallic braid. Braid, wrap the outside of the cable like a sock.
4
The capacity of the antenna cable with the goal of lengthening is made through a device connector, the usual twisting or soldering will lead to a deterioration of the operating parameters of the cable. Another option of increasing the antenna cable using a special flexible cord. Assembled extension cable is a drum placed on it flexible antenna wire, the closed plastic housing.
5
When using hard antenna cable should not bend or collapse the coils – this can lead to a significant deterioration of signal quality.
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