Logoperiodic antennas: calculation of sizes and main characteristics

Logoperiodic antennas belong to the class of directional devices. Models, as a rule, work on short waves. Most devices are equipped with a high-conductivity reflector. Some modifications are made with a panel vibrator. They have one or more amplifiers. Also it should be noted that there are devices with channel transmitters.

What are the main parameters of log-periodic type antennas? First of all, it is important to consider the frequency of devices. The specialists also consider the directivity and amplification factor. The input impedance also affects the antenna parameters.

Model Calculation

Calculation of the antenna is based on the length of the rack. If we consider models with a single vibrator, then the reflector is of the dipole type. At a length of 20 cm, the width of the panel should be 30 cm. With the increase in the size of the rack, the panel is selected corresponding dimensions.

The device itself

Logoperiodicheskaya antenna with their hands folds with a simple reflector, and the vibrator is more appropriate to use with an extension cord. First of all, the mast is put directly. The posts are fixed using a welding machine. Experts advise to install the amplifier immediately.

Wiring must only be used with grounding. To reduce the frequency, different types of expanders are used. Most models work from contact adapters. The upper posts should be of small diameter. It is also necessary to pay attention to the lower adapter, from which the wire departs. Depending on the calculation of the model, the dimensions of the log-periodic antennas depend.

Model for a simple receiver

Logperiodic antennas for simple receivers are manufactured with masts of low height. The most common are the modifications to the three racks. If we consider an antenna with a single adapter, then the reflector is applied with a capacitor. Also it should be noted that the mast is fixed on the rack. The shout in this case is very rare. Adapters at the antenna are fixed through the holders. Experts say that the most popular models are those with dipole adapters. They can work on a short wave.

Device with one rack

An antenna with one rack is not distinguished by high conductivity. On the market there are devices with back vibrators. They use a fairly wide support. In this case, the holders are set to a small width. If we consider a standard antenna of the log-periodic type, it has one reflector. Racks are installed on the mounting bracket. Often antennas are sold without holders. They stand with a wide base. The most high-quality devices are considered to be with enhanced adapters. Vibrators can also be installed without an adapter. Racks in this case are of small length.

Model with two racks

Logoperiodic DMV antenna with two racks is made with a reflector for three channels. Experts say that models have different conductivity. When choosing a modification, it is necessary to pay attention to the modification support. The holders can be L-shaped. Quite often antennas of this type are installed on the roof.

Devices are well suited for making a television channel. However, they are not able to work at all frequencies. In this case, much depends on the shape of the reflector. Modern modifications of the logoperiodic type antennas are used with output amplifiers. Only open adapters are installed under them. In this case, the vibrators are mounted in the central part of the rack. Masts differ in length. Much depends on the width of the racks. The conductivity of the modification depends on the reflector. The wire from the antenna must move away from the expander.

Horizontal antennas

A horizontal antenna for TV log-periodic type is distinguished by a wide rack. Many models use a long mast, and the supports are made only of an aluminum alloy. If desired, such an antenna log-periodic type can be done independently. It is good for a receiver of low power. Specialists say that in the first place the holder is put. Only after this you can install the mast. The next step is to put a reflector. If we consider shop modifications, they have two vibrators.

Most models are made without stops. Their posts are in a horizontal position. To install a log-periodic type antenna, wide metal fasteners are used. Also it should be noted that there are modifications of high frequency, in which the amplifier is installed. Expanders for devices are selected only for high conductivity. Quite often in the market there are devices with negative polarity. First of all, experts note that they have no problems with short waves, and very high gain. The dimensions of the log-periodic antennas directly depend on the calculations of the model.

Vertical modifications

Often in shops there is a vertical log-periodic antenna. The model is calculated based on the dimensions of the rack. Vertical log-periodic type antennas are manufactured with reflectors of different conductivity. Most models are made on contact adapters.

Also in stores you can find devices without amplifiers. As a rule, they use short reflectors, and the vibrators are set short-wave type. The minimum permissible frequency of an antenna depends on many factors. In this case, the user must take into account the resistance of the reflector. In addition, you need to know the type of expander. Most models are sold with conventional controllers.

144 MHz device

Logoperiodic antennas of this type are made with long posts, and vibrators are used with supports. The standard model includes one connector. Amplifiers for these log-periodic antennas are installed with different power. Additionally, it is important to remember that modifications differ in conductivity. Some devices are made with one rack. They have a small input resistance. As a rule, they are produced with an output vibrator. The holders are set to a small height. If desired, such an antenna log-periodic type can be done by any person. In this case it is important to calculate the height of the rack.

Modification to 145 MHz

An antenna for TV of this type is made only with a dipole reflector. In this case, the vibrators are used with medium conductivity. Experts say that on the market quite often there are modifications with wire adapters. Reflectors they are installed on the racks. The side supports can be very large. Also, the high level of resistance of these log-periodic antennas deserves attention.

If desired, the model can be assembled at home. Specialists for this purpose use metal racks, which are connected together by a welding inverter. The vibrator is used with one output. The wire from the antenna is fixed on the expander. As a rule, it is mounted at the bottom of the mast.

Model with copper mast

Logoperiodic antenna for T2 with a copper mast works remarkably at different frequencies. The standard model includes a contact adapter, which is fixed at the bottom of the rack. Vibrators for models are only used with the expander. Also it should be noted that the stores have antennas with wide reflectors. Most of them can work at low frequencies. Experts say that there are devices of reverse polarization. For them, expanders are used with contact reflectors. Some models are equipped with amplifiers that connect to the sub.

Devices with steel mast

Logperiodic antennas with a steel mast can be made independently. Specialists recommend to harvest wide supports for this. Most models have high conductivity, and they are well suited for signal reception. The vibrators of the models are of different sensitivity. In this case, the amplifiers, as a rule, are installed in the lower part of the masts. Experts argue that the adapter should be fixed only through a transistor and power supply.

In addition, it is important to note that when assembling the model, problems with the racks may arise. If we consider the store antennas, then they have a wide holder. In this case, the front supports are securely fixed directly to the mast of the device.