An VHF antenna is a device that is designed to receive radiation. These modifications are able to work only with short-wave signals. Models differ in frequency. Do-it-yourself antenna for a VHF radio receiver is assembled according to the instructions. In this case, it is important to consider the type of receiver. In addition, it should be noted that there are various types of antennas that differ in design and parameters.
Simple receiver model
The do-it-yourself antenna for a VHF receiver develops most often on a vertical stand. At the same time, it is more advisable to use short balances. To fix the supports, a welding inverter is used. First of all, the mast is prepared on which the supports will be held. Its diameter should be at least 1.2 cm. Reflectors are used to enhance signal reception. In many versions, the racks are installed at a slight angle.
The base of the antennas must be made with an overlay. In this case, the balances are allowed to fix on electrical tape. Experts say that steel tubes are suitable for this. For models with a negative directivity, a reflector is used. The specified element is mounted on the edge of the mast.
Single rack device
Do-it-yourself antenna for a VHF radio receiver is made with different frequencies. Models differ in conductivity and gain. When assembling the device, it is important to prepare a solid mast. Experts advise using hollow racks with low weights. Its diameter should be at least 2.2 cm. If we consider models for low-frequency receivers, then the balances can be selected from stainless steel. It is not necessary to install the pads.
Antenna reflectors are used at different frequencies. On the market, modifications with petals are often found. They have high gain. However, it should be noted that they are difficult to make on their own. The front stops can be soldered using a welding inverter. The edges of the antenna must be carefully sanded. Racks should be used with a diameter of 0.3 cm. To combat resonant interference, special high-conductivity impulse reflectors are used. Models with horizontal stops are produced with only one mast.
Model with two racks
With two racks, the VHF antenna is assembled on a wide mast with its own hands. Models of this type are suitable for receivers of different series. As a rule, models have a high resistance parameter, they are able to work at a frequency above 300 MHz. Many devices use multiple reflectors. During the assembly of the model, you need to tackle the central mast. As a rule, specialists use tubes of small diameter with sharpened ends. It should also be noted that there are models with tips. In this case, the balances can be installed at different angles. The stand length of a simple antenna is 22 cm.
To increase the gain, steel tubes are used. There are also petal modifications. They operate at a frequency of 200 MHz. The direction of action of the antennas may vary. The bottom of the device rack is insulated. The reflector must be well fixed. The counterweight can be installed horizontally.
It should also be noted that to overcome phase noise it is worth using elongated reflectors. The mast must withstand heavy overloads. Antennas of this type do an excellent job with negative polarization. However, in this case, it is necessary to take into account the type of receiver and its maximum frequency.
Horizontal antennas
Horizontal antennas can be assembled with different balances. Simple modifications are made on straight masts. There are also many high-frequency devices that are manufactured with a linear reflector, which is installed at the base of the rack. Horizontal antennas have a high impedance coefficient. They are capable of operating at a frequency of 200 MHz.
Many models are equipped with dual counterweights. At the same time, masts are used with a diameter of 1.2 cm or more. Some devices are suitable for working with domestic receivers. They have a high standing wave ratio. Racks are most often installed at right angles. Counterweights are located only at the front of the device.
Vertical modifications
Vertical antennas are capable of operating at different frequencies. Modifications of this type have a high gain. Do-it-yourself vertical VHF antenna for the radio is quite simple. First of all, you need to choose good racks, prepare the welding inverter in advance. To solve problems with negative polarization, it is recommended to use pulse reflectors. In this case, the balances must be set to a large length, and their diameter should not be less than 0.3 cm. Filters are used to strengthen the directivity. Front struts may be mounted at an angle of 45 degrees. However, the mast strength must be calculated in advance.
To increase the stability of the structure, the base can be made with stops. Do-it-yourself VHF antenna for radio is assembled only with short racks, which must be installed at a low height. Counterweights are allowed to wind on a rack. In this case, take care of the overlays. Special attention is paid to lateral surveys, which are recorded on the mast. To increase the dispersion area, it is recommended to use racks with a length of 25 cm or more.
144 MHz device
The 144 MHz VHF antenna is made with a direct or curved stand. The mast in this case is used with oblique stops. In some cases, pulse reflectors are used. Going to do-it-yourself VHF antenna 144 with side racks. The optimal length of the supports is 15 cm. Front brackets are used to increase the gain. As a rule, they are mounted with overlays. 144 MHz VHF antenna is done with one or two stops.
145 MHz modification
145 MHz do-it-yourself VHF antenna is done with a short mast. The most common are modifications with three racks. The gain of the models is quite high. Antenna guides are used with pulse reflectors. Front supports can only be installed using a welding inverter. Models have a high directivity. Experts say that antennas are allowed to be made with curved masts.
Copper mast model
The antenna for the VHF band is being developed with your own hands with reflectors of different frequencies. Front struts are allowed to be installed with and without overlays. Some modifications are made on the side pillars. Antennas are manufactured with a high dispersion coefficient. The mast is mounted first. Counterweights can be mounted at a slight angle.
The optimal diameter of the racks is 1.2 cm. In this case, the mast is more appropriate to use with a solid base. If we talk about the reflector, then it must be used pulsed or wired type. To make a simple model, four counterweights are used. Pads are soldered using a welding inverter. Next, to make the device with your own hands, partitions under the mast are installed. Strengthening the dispersion area can be achieved using the side pillars.
Steel mast devices
On a steel mast, a VHF antenna is made with diagonal holders. Counterweights are usually installed on one side. Some experts recommend using short racks with a diameter of 2.2 cm or more. To enhance the directivity of the device, a pulse reflector is used, which is mounted at the base of the antenna. To connect the model, a conductor from the mast is used. It is also worth noting that there are devices with side lobes. They have high conductivity.
Devices for low sensitivity receivers
For low-sensitivity receivers, a DIY VHF antenna is assembled quite simply. The first step is the mast to which the side posts are attached. Counterweights are often used with skew guides. The match is set with a solid base. For models of this type, a wired reflector should be used. Counterweights may be installed horizontally. To enhance the gain, it is allowed to mount long racks with a diameter of 2.2 cm or more.
High Sensitivity Receiver Models
For these receivers, the 430 MHz VHF antenna is done with a steel mast by hand. Some experts strongly recommend using only curved racks. In this case, the balances must be mounted at the base of the frame. A regular VHF antenna is made with different types of reflectors.
It is more expedient to start assembling the modification by fixing the mast and removing the wire for connection. Further, to make the device with your own hands, you will need to cut four racks with a diameter of 2.2 cm. For the 200 MHz model, you need three side racks. Counterweights may be installed at an angle of 45 degrees. The front legs are mounted at the bottom of the mast.