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Modulators. Schemes, articles, descriptions

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Seven Band Antenna

HF Antenna Section. We offer a two-tier antenna operating on 10, 12, 15, 17, 20, 40-80 meters of the HF band. The upper tier (B) works on 10, 15, 20, 40, 80 meters, the lower tier (H) - on 12 and 17 meters (Fig. 1). The input impedance (V) is 180 220 ohms, (H) 45 50 ohms. The antenna is powered by two coaxial cables, separately for each tier (Fig. 2). The transformer Tr1 with a ratio of 1: 4 is wound on a ferrite ring with a diameter of 60 mm and a height of 10 mm, the permeability is 400 600. It is wound simultaneously with two wires with a diameter of 1,5 mm or a line with a wave resistance of 100 Ohm - evenly along the ring, 10 turns. You can use transformers from the RV-12 antenna ... >>

Quartz calibrator

Section Measuring technology. To adjust, adjust and calibrate the scales of radio receivers and amateur radio measuring generators and to verify them during long-term operation, a signal source of a higher accuracy and stability class is needed. The proposed version of the quartz calibrator provides at the output a grid of modulated harmonics of the fundamental frequency of the used quartz resonator. So, when using quartz with a nominal frequency of 100 kHz, the 16th harmonic is easily detected on a receiver with a KB range of 19 - 160 m. Such a device can be useful not only for radio amateurs, but in some cases in service departments, at enterprises. The design of the calibrator is simple in terms of circuitry, does not contain scarce radio elements, has small dimensions and is easy to adjust. In a copy of the test device made by the author, it was shown that without additional adjustments, quartz resonators with a frequency of up to 15 MHz are confidently excited, which makes it possible to expand the grid of calibration marks up to the frequencies of the television ranges of meter waves. ... >>

Introductory device

Electrical section. The introductory device provides automatic shutdown of all consumer electrical wiring in the event of a malfunction, and also allows you to turn off the wiring during repairs or for a period of prolonged inactivity. In modern apartment buildings, the input device is located in common vestibules or on stairwells, in one- and two-story buildings - usually outside on the wall. The input device can be a fuse or some other protective device, such as a circuit breaker. For a single-family house, the rated current of the protective device is not more than 25 A. At the inputs to an apartment building or in cases where single-phase electrical receivers with a power of more than 1,3 kW are used, a device for a current of more than 25 A may be required ... >>

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Articles on modulators

Articles on modulators; modulator circuits; descriptions of modulators: 8 articles



All articles on amateur radio components



Latest news of science and technology, new electronics:

The speech of sperm whales is similar to that of humans 18.05.2024

In the world of the ocean, where the mysterious and unknown coexists with the studied, sperm whales, with their huge brains, are of particular interest to science. Researchers, working with a huge array of audio recordings collected during the Dominica Sperm Whale Project (DSWP) - more than 8000 recordings, seek to unravel the secrets of their communication and understand the structure and complexity of the language of these mysterious creatures. By studying in detail the recordings of 60 sperm whales in the eastern Caribbean, scientists have revealed surprising features of their communication, revealing the complexity of their language. "Our observations indicate that these whales have a highly developed combinatorial communication system, including rubato and ornaments, which indicates their ability to quickly adapt and vary during communication. Despite significant differences in evolution, sperm whales have elements in their communication that are characteristic of human communication," says Shane Gero, a biologist at Carleton University and director of the CETI project. Issl ... >>

Electron spin for quantum information transfer 18.05.2024

The transfer of quantum information remains one of the key tasks of modern science. Recent advances in the use of electron spin to expand the capabilities of information transfer in quantum systems have become very important. Researchers at Lawrence Berkeley National Laboratory are pushing the frontiers of quantum information science by experimenting with the possibilities of electron spin. Electron spin, a natural quantum bit, is a potentially powerful means for storing and transmitting information in quantum systems. Magnon wave packets, collective excitations of electron spin, have revealed their potential to transmit quantum information over significant distances. The work of Berkeley Lab researchers has revolutionized the way such excitations propagate in antiferromagnets, opening up new prospects for quantum technologies. Using pairs of laser pulses, scientists disrupted antiferromagnetic order in one place and simultaneously studied it in another, creating ... >>

Sound-absorbing silk 17.05.2024

In a world where noise is becoming increasingly intrusive, the emergence of innovative materials that can reduce its impact is of great interest. MIT researchers have unveiled a new sound-absorbing silk fabric that promises to revolutionize quiet spaces. The Massachusetts Institute of Technology (MIT) has made significant breakthroughs in the field of sound absorption. Researchers have developed a special silk fabric that can effectively absorb sound and create cozy, quiet environments. The fabric, thinner than a human hair, contains a unique vibrating fiber that is activated when voltage is applied to it. This feature allows the fabric to be used to suppress sound waves in two different ways. The first method uses fabric vibrations to generate sound waves that cover and cancel out unwanted noise, similar to noise-canceling headphones. This p ... >>

Random news from the Archive

Little Wi-Spy Scout 30.06.2006

The young company MetaGeek (Idaho, USA) has released the world's smallest and most inexpensive spectrum analyzer.

Wi-Spy is no bigger than a USB storage device, weighing just 8g and costing less than $5, 100 times less than the nearest competitor. The spectrum analyzer can find noise-free portions of the spectrum in the frequency range from 40 to 2 GHz and solve problems associated with cordless phones, Bluetooth and ZigBee devices, 4b/g networks, and other wireless systems that use this frequency range. .

The analyzer with built-in antenna and trigger connects to a USB 1.1 or 2.0 port on a Windows, Linux, or Mac host computer and scans the entire operating frequency range in 96 ms at 1 MHz and 1 dBm resolution. The control and display software is supplied with the analyzer and provides a spectral display of the measured data in various coordinates (amplitude, frequency, time).

Other features of the device include analysis of the average, maximum and current signal level; frequency and amplitude markers; viewing the amplitude of Wi-Fi channels; recording and playback; copying and printing of measured data.

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