QRP technique. Schemes, articles of the Free Technical Library

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QRP technique. Schemes, articles, descriptions

Free library / Schemes of radio-electronic and electrical devices

QRP technique

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Calculation of the wind wheel

Section Alternative energy sources. The main part of the wind turbine is the wind wheel. Through it, the kinetic energy of the wind is converted into mechanical energy. Recall wind turbines are divided into two groups - with a horizontal and vertical axis of rotation. We will consider a wind turbine with a horizontal axis of rotation. It may have one or more blades, which are installed at some angle to the plane of rotation. The wind wheel can be fast or slow. Depending on the diameter and number of blades, the speed of the wind wheel at the same wind speed will be different. ... >>

Fluorescent lamps for lighting aquariums

Section Fluorescent lamps. Let's look at some series of special-purpose lamps. The OSRAM FLUORA® LL series has a special radiation with a predominant blue and red component, similar to the radiation that promotes photochemical processes. Thanks to this radiation, plant growth is noticeably accelerated. These lamps are designed for lighting plants and aquariums. Lamps in this series are made on the basis of a tube with a diameter of 26 mm. PHILIPS produces a series of special lamps for aquariums - Aquarelle (Watercolor). The special emission composition of this fluorescent lamp is ideal for conveying the beauty of fish and plants in a freshwater aquarium ... >>

Expansion of the TV frequency range for receiving transmissions via cable networks

Section Television. Recently, multi-channel cable TV networks have become more widespread, however, the CM band of 110-174 MHz, often used by them, located in a hole between 5 and 6 channels of the usual terrestrial MV band, does not allow reception on TV receivers 2, 3 and 4 generations. I offer several tried and tested ways to refine the PTK and selectors. PTK-3, PTK-10, PTK-11. They are used in tube black-and-white TVs, which many viewers still have. Since some channels of the I-II and III bands are not used for broadcasting over cable networks, it is necessary, after removing the drum from the PTK, to remove the antenna and heterodyne sectors of unused channels and install sectors with converted coils in their place ... >>

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Articles on QRP technique

Articles on QRP technique; schemes of QRP technique; QRP technique descriptions: 5 articles

All articles on civil radio communication

Latest news of science and technology, new electronics:

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

The threat of space debris to the Earth's magnetic field 01.05.2024

More and more often we hear about an increase in the amount of space debris surrounding our planet. However, it is not only active satellites and spacecraft that contribute to this problem, but also debris from old missions. The growing number of satellites launched by companies like SpaceX creates not only opportunities for the development of the Internet, but also serious threats to space security. Experts are now turning their attention to the potential implications for the Earth's magnetic field. Dr. Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics emphasizes that companies are rapidly deploying satellite constellations, and the number of satellites could grow to 100 in the next decade. The rapid development of these cosmic armadas of satellites can lead to contamination of the Earth's plasma environment with dangerous debris and a threat to the stability of the magnetosphere. Metal debris from used rockets can disrupt the ionosphere and magnetosphere. Both of these systems play a key role in protecting the atmosphere and maintaining ... >>

Solidification of bulk substances 30.04.2024

There are quite a few mysteries in the world of science, and one of them is the strange behavior of bulk materials. They may behave like a solid but suddenly turn into a flowing liquid. This phenomenon has attracted the attention of many researchers, and we may finally be getting closer to solving this mystery. Imagine sand in an hourglass. It usually flows freely, but in some cases its particles begin to get stuck, turning from a liquid to a solid. This transition has important implications for many areas, from drug production to construction. Researchers from the USA have attempted to describe this phenomenon and come closer to understanding it. In the study, the scientists conducted simulations in the laboratory using data from bags of polystyrene beads. They found that the vibrations within these sets had specific frequencies, meaning that only certain types of vibrations could travel through the material. Received ... >>

Random news from the Archive

Spider venom will save you from a heart attack 03.08.2021

The bite of a funnel-shaped spider that lives on the Australian Fraser Island is fatal. But the spider's venom could also be a lifesaver - scientists have developed a drug candidate based on a molecule found in the venom of funnel-web spiders. Drugs based on this molecule could be used to treat patients with a heart attack.

Australian scientists have tested the Hi1a protein as a drug candidate to prevent the death of heart cells. A heart attack causes oxygen deficiency, which leads to the oxidation of the environment of the cell. In fact, this becomes a signal for cells to die. However, a protein from the Hi1a spider venom can stop this signal from being sent.

Funnel-web spiders are poisonous, but thanks to modern first aid methods and antidotes, no one has died from them lately. However, spider venom is a very effective compound that scientists want to use to save lives. So far, there are no drugs that could stop the transmission of the aforementioned signal. This means that Hi1a could save hundreds of thousands of heart attacks and transplant patients.

Cell engraftment is important in heart transplantation. Hi1a can reduce cell death and make heart transport and transplantation more successful. The scientists tested the Hi1a protein on beating human heart cells and found an improvement in their survival.

Professor Peter McDonald, one of the authors of the study, says: "Normally, if a donor heart stops beating for more than 30 minutes before extraction, it is no longer usable. And if we can get an extra 10 minutes, it will make a huge difference. For people who are literally standing on the verge of death, it can bring back life."

In a heart attack, Hi1a can be given as an injection as first aid. Such a drug will significantly improve the outcome of a heart attack and increase survival. This will be of particular importance for residents of rural areas, where the road to the nearest hospitals is usually very long.

Poisons have long been successfully used in medicine. Various snake venoms are used in the treatment of heart diseases and in the form of painkillers. These are very powerful compounds that scientists are learning to use for peaceful purposes, and not as laid down by nature.

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