Combined TV antenna. Scheme, description

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

Combined TV antenna. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Television antennas

Comments on the article

Currently, on-air television broadcasting covers the frequency range from 48,5 to 790 MHz. To receive signals in such a wide frequency band, either several separate antennas (each for its own frequency section) or one combined antenna are used, since the construction of ultra-wideband antennas is a rather complicated technical task.

An example of a combined antenna is the currently widespread 4-element antenna array made in Poland. A sample of such an antenna for UHF is described in [1]. Only for the Polish antenna, the upper vibrator is longer and extends beyond the screen, which ensures reception of signals in the MB band.

However, the gain and, accordingly, the cost of such an antenna for use at distances up to 10 km from the transmitting antenna with modern TVs are excessive. In addition, an antenna for self-production at home should be simple and allow the use of various improvised materials. These considerations formed the basis of the proposed ultra-wideband television antenna (Fig. 1), consisting of two antennas for MB and UHF, without the use of means for matching the antenna with the feeder.

Fig.1. Combined television antenna

For reception in the UHF range, a wave broadband vibrator is used, described in [2]. Compared to the half wave vibrator, it has a narrower radiation pattern, higher gains and output impedance.

For reception in the MB range, a broadband vibrator is also used. Its shoulders are made of cylindrical spirals. They can be considered as inductances or retarding structures [3]. Its closest analogue is the TAI-12 antenna, which has been produced by the industry for a long time and is described in detail in [4]. To reduce the dimensions of the entire antenna, the arms of the vibrators are made of aluminum wire d3 mm and contain 6 turns each, made on a mandrel d36 mm and stretched to a distance of 0,5 m. The blank for the manufacture of the element has a length of 1,1 m. windings must match. All antenna elements are connected at points "A" and "B" with M4 screws 20 ... 25 mm long. A 75-ohm television cable is directly connected to the same points using petals.

In a frequency band of more than one decade, it is impossible to use one matching device with satisfactory frequency characteristics and easy to manufacture. The use of two matching devices complicates the manufacture of the antenna and its adjustment. Therefore, in order to simplify the antenna, a direct connection of the coaxial feeder was chosen. In this case, the antenna operates with a large SWR, i.e. in a mismatched and asymmetric mode. Since the output impedances of wave vibrators are large, changes in the degree of agreement (or mismatch) over the range are smoothed out. The greatest deterioration in the quality of the received signal is observed on the 2nd and 51st frequency channels.

Such an antenna can provide acceptable quality only under obviously good reception conditions. So, one copy of the described antenna was installed in the attic of a 2-storey building with direct visibility to the transmitting antenna located at a distance of 5 ... 6 km, and provided a decent picture.

The DMV vibrator can be made of various materials. The easiest way to make it at home is by sticking an aluminum capacitor foil onto a substrate made of polystyrene, organic glass, or other material with good high-frequency properties.

In the presence of the necessary materials, the manufacture of such an antenna takes 1 ... 2 hours. It is possible to improve the antenna by applying the matching of the antenna with the feeder and its balancing, as well as by making the antenna array from several elements.

Literature

Spindler E. Practical design of antennas. - M.: Mir, 1989.
2. Rothammel K. Antennas. - M.: Energy, 1979.
Sovetov N.M. Microwave technology. Proc. allowance for universities - M.: Higher school, 1976, p.135.
Television antennas for 12 channels. - Radio, 1959, N5, S.57.

Author: E. Solodovnikov, Krasnodar; Publication: radioradar.net

See other articles Section Television antennas.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive

Asus X79-Deluxe motherboard 12.09.2013

Asus has released the X79-Deluxe motherboard, designed for LGA2011 processors, including the recently introduced Intel Core i7 Extreme (Ivy Bridge-E) processors.

The design of the board size ATX used black and gold colors. The power subsystem is built according to a 10-phase scheme. Power is supplied via a 24-pin ATX connector and an 8-pin EPS connector. The board has eight DDR3 DIMM slots, four PCI-Express 3.0 x16 slots, and two PCI-Express 2.0 x1 slots.

Equipped with eight SATA 6Gb/s ports and four SATA 3Gb/s ports, as well as two eSATA 6Gb/s ports. The number of USB 3.0 ports is eight, and six of them are displayed on the rear panel. An important feature of the X79 Deluxe board is the WiFi GO! wireless module, which supports 802.11ac and Bluetooth 4.0.

Wired network connectivity is provided by two Gigabit Ethernet ports. An eight-channel sound subsystem and USB 2.0/1.1 ports complete the picture. The board uses proprietary technologies Asus USB BIOS Flashback, EPU, TPU II, SSD Caching and USB 3.0 Boost.

The expected price of Asus X79 Deluxe is $350.

Other interesting news:

▪ Wireless electricity

▪ Indoor flower - mini power plant

▪ VR headset from Korea Fuel-Tech Corporation

▪ Toyota electric vehicles with solid state batteries

▪ Specifications of glasses-computer Glass

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Radio - for beginners. Article selection

▪ article The past is the best prophet of the future. Popular expression

▪ article Why do horses ride in the saddle? Detailed answer

▪ article by Strophant Combe. Legends, cultivation, methods of application

▪ article Bell with remote control. Encyclopedia of radio electronics and electrical engineering

▪ article AM-FM radio receiver with low-voltage power supply. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

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