Antenna Mussel. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / VHF antennas
Comments on the article
A simple dual-band antenna for frequencies of 260-390 MHz, the radiation pattern is ellipsoid, the signal gain compared to a half-wave dipole is at least 3 dB.
The vibrators are made in the form of circles, the length of the conductors of which is equal to the wavelength.
The length of the conductors is calculated by the formula:
L=300/F,
where L is the length of the conductor in meters;
F is the operating frequency of the antenna in megahertz.
A 50 ohm cable is connected to the antenna through an impedance matching transformer made in the form of a cable segment with a wave impedance of 75 ohms, the length of this segment is 150 mm.
Author: Vasily Vasilenko, Yakutsk; Publication: inspector_v.chat.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 Wearable sensor warns of stroke risk
27.01.2015
Created by Samsung Electronics two years ago, the Creativity Lab or C-Lab, a research unit, has created a wearable sensor that can detect an approaching stroke. The source notes that medical experts expressed doubts about the possibility of implementing the idea, but this did not stop a group of five engineers.
Stroke is a dangerous and, unfortunately, a very common violation of cerebral circulation. In the sad statistics of mortality from cardiovascular diseases, cerebrovascular accidents take the second place after coronary heart disease. Every year, about 15 million people worldwide have a stroke. Approximately 66% of cases end in death or disability. Timely diagnosis of a stroke is extremely important, because the patient's life depends on how soon medical care is provided.
This month, C-Lab developers unveiled a prototype solution called the Early Detection Sensor & Algorithm Package (EDSAP). His work is based on the analysis of brain waves. The solution includes a sensor and an algorithm for processing the data obtained with its help. The processing results are available for viewing on a smartphone or tablet. Observation of the sensor readings makes it possible to notice violations in a timely manner and seek medical help.
In addition to detecting signs of a stroke, EDSAP makes it possible to monitor the patient's condition by obtaining information about the state of his nervous system, for example, to identify the presence of stress and fatigue, to analyze sleep.
From similar solutions already on the market, EDSAP compares favorably with portability and speed - now such an analysis of brain activity requires about 15 minutes in a medical institution. In addition, the sensor uses a new conductive rubber-like material developed by C-Lab, which provides improved measurement accuracy. The sensor is easy to wear and does not require saline to wet your hair to install. The most important thing, according to the developers, is that the sensor can be reduced and built into a more familiar everyday thing like a pair of glasses or a hair clip. So it can be worn for a long time without burdening yourself and without attracting the attention of others.
Developers see the development of EDSAP in the creation of other similar solutions for related applications, including monitoring of cardiac activity.
|
Other interesting news:
▪ Hydrogen converted to metal
▪ Mobile phone tracked by a special signal
▪ Marriage affects blood sugar
▪ Fungal extract against cancer
▪ New Model Spectrum Analyzer
News feed of science and technology, new electronics
Interesting materials of the Free Technical Library:
▪ section of the site Experiments in chemistry. Article selection
▪ Third world article. Popular expression
▪ article Are there seas on the moon? Detailed answer
▪ tandem article. Personal transport
▪ article Intercom with time division of channels. Encyclopedia of radio electronics and electrical engineering
▪ article Transistor voltage converter. 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
www.diagram.com.ua
2000-2024
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese