Antenna at 144 MHz. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / VHF antennas

 Comments on the article

I want to bring to the attention of the readers of the magazine the design of the antenna, obtained as a result of experiments with loop antennas. The proposed antenna may be of interest to radio amateurs operating on the VHF bands and not having the opportunity to manufacture or install an antenna with an extended traverse.

This antenna is a modified design of a zigzag antenna, described by K. Kharchenko [1] and has proven itself when receiving TV signals. The general view of the antenna is shown in Fig.1.

Ris.1

The antenna is designed to operate in the amateur range of 2 m. It is small in size, does not require special material costs and careful tuning. At the same time, the antenna has pronounced directional properties, is quite broadband, is in good agreement with the feeder and has a high gain.

In this example, the antenna radiates or receives a vertically polarized wave. To work with horizontal polarization, the antenna must be rotated along the axis by 90 °, and it is desirable to change the shape of the elements to diamond-shaped. The antenna elements are made in the form of equilateral triangular frames of aluminum wire with a diameter of 5 mm. You can use a rod or tube made of copper, brass or bimetal with a diameter of 4 to 9 mm. In this case, the design will be heavier.

All sides of the frames are the same. The length of the side of the triangle at the reflector is 740 mm, at the vibrator - 700 mm, at the director - 665 mm. The total perimeter of the reflector is 4400 mm, the vibrator is 4200 mm, the director is 4000 mm. A deviation in dimensions of 10 ... 20 mm is allowed. The distance between the reflector-vibrator is 480 mm, the vibrator-director is 280 mm.

The frames are made from a single piece of wire.

Ris.2

In the geometric center of the reflector and director (point "A" in Fig. 2 and 3), the conductors are short-circuited with a rivet.

Ris.3

If possible, it is also desirable to solder the junction to ensure reliable galvanic contact. At the vibrator, the conductors in the center are spaced 10 ... 20 mm (Fig. 4).

Ris.4

At this point, a feeder is connected to the vibrator. The central core of the cable is connected to the lower terminal of the vibrator in relation to the ground (point "a"), and the cable braid is connected to the upper terminal (point "b").

The antenna frames are fixed on the pads from the insulator with the help of clamps. Platforms measuring 100x120 mm are made of textolite 5 mm thick, but other insulating material (plexiglass, ebonite, etc.) can also be used.

With the help of small corners, the platforms with frames are attached to the traverse. The carrier is made of a wooden block with a section of 30x40 mm and a length of 1 m. The antenna is attached to the mast in the manner indicated in the drawing (Fig. 5).

Ris.5

As a feeder, you can use a coaxial cable with a characteristic impedance of 50 or 75 ohms.

In this case, a factory-made VHF reflectometer was used to assess the degree of matching of the antenna with the feeder. SWR in the feeder at frequencies 145 ... 145.7 MHz - 1: 1,1.

The gain in voltage at the receiving point compared to the GP antenna was U1/U2=1:5,18.

The antenna showed very good results when receiving TV signals on the UHF. The antenna designed for the 30th channel covers the entire UHF television section.

Literature

1. Kharchenko K. Zigzag antenna. - Radio, 1962, N11; 1977, N6.

Author: S.Machuga (US5MGZ); Publication: N. Bolshakov, rf.atnn.ru

See other articles Section VHF antennas.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

A New Way to Control and Manipulate Optical Signals 05.05.2024

The modern world of science and technology is developing rapidly, and every day new methods and technologies appear that open up new prospects for us in various fields. One such innovation is the development by German scientists of a new way to control optical signals, which could lead to significant progress in the field of photonics. Recent research has allowed German scientists to create a tunable waveplate inside a fused silica waveguide. This method, based on the use of a liquid crystal layer, allows one to effectively change the polarization of light passing through a waveguide. This technological breakthrough opens up new prospects for the development of compact and efficient photonic devices capable of processing large volumes of data. The electro-optical control of polarization provided by the new method could provide the basis for a new class of integrated photonic devices. This opens up great opportunities for ... >>

Primium Seneca keyboard 05.05.2024

Keyboards are an integral part of our daily computer work. However, one of the main problems that users face is noise, especially in the case of premium models. But with the new Seneca keyboard from Norbauer & Co, that may change. Seneca is not just a keyboard, it is the result of five years of development work to create the ideal device. Every aspect of this keyboard, from acoustic properties to mechanical characteristics, has been carefully considered and balanced. One of the key features of Seneca is its silent stabilizers, which solve the noise problem common to many keyboards. In addition, the keyboard supports various key widths, making it convenient for any user. Although Seneca is not yet available for purchase, it is scheduled for release in late summer. Norbauer & Co's Seneca represents new standards in keyboard design. Her ... >>

The world's tallest astronomical observatory opened 04.05.2024

Exploring space and its mysteries is a task that attracts the attention of astronomers from all over the world. In the fresh air of the high mountains, far from city light pollution, the stars and planets reveal their secrets with greater clarity. A new page is opening in the history of astronomy with the opening of the world's highest astronomical observatory - the Atacama Observatory of the University of Tokyo. The Atacama Observatory, located at an altitude of 5640 meters above sea level, opens up new opportunities for astronomers in the study of space. This site has become the highest location for a ground-based telescope, providing researchers with a unique tool for studying infrared waves in the Universe. Although the high altitude location provides clearer skies and less interference from the atmosphere, building an observatory on a high mountain poses enormous difficulties and challenges. However, despite the difficulties, the new observatory opens up broad research prospects for astronomers. ... >>

Random news from the Archive Single Chip MT7628 Wi-Fi System 2T2R 802.11n 19.09.2014 MediaTek has unveiled the MT7628 single-chip system, which is the first SoC for 2T2R 802.11n Wi-Fi access points and routers, according to the manufacturer. The advantages of the new SoC include a high degree of integration and low power consumption. By combining a 2T2R 802.11n Wi-Fi RF module with a MIPS 24KEc processor running at 580 MHz, power consumption is 18% lower than other similar solutions on the market. The MediaTek MT7628 is equipped with a five-port Fast Ethernet switch and a large number of interfaces, including USB, PCIe, SD-XC, I2S/PCM and numerous low-speed interfaces, allowing you to easily connect to a wide range of Internet of Things (IoT) devices. MT7628 can operate in one of two modes: Router or IoT. In the second mode, SD-XC, eMMC, PWM, SPI slave interfaces, a third UART transceiver and more GPIO lines are available; in router mode, the PCIe interface is enabled, which is used to connect 802.11ac chipsets. The presence of USB 2.0 makes it possible to connect a 3G / LTE modem or an IP camera that transmits video in H.264 format. The ability to organize a PCIe-to-SATA bridge is useful when using the MT7628 in a NAS. The MT7628 family includes two models: MT7628K and MT7628A. A feature of the first is the presence of built-in DRAM memory, and the second is designed for external memory. The appearance on the market of devices based on MT7628 is expected in the next quarter.

Other interesting news:

▪ Spray that turns off the action of genes

▪ New record in the field of high-temperature superconductivity

▪ Liquid metal remembers its original shape

▪ Frequent smartphone use harms the spine

▪ Mining uranium from sea water

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Encyclopedia of radio electronics and electrical engineering. Article selection

▪ article Harmful impurities of pyrogenic origin. Fundamentals of safe life

▪ article At what holiday did the British burn cats alive in the 17th century? Detailed answer

▪ article Climbing pandanus. Legends, cultivation, methods of application

▪ article Multivibrator - flasher. Encyclopedia of radio electronics and electrical engineering

▪ article Charger with temperature compensation. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024