Radio transmitter with FM in the VHF frequency range 61-73 MHz. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Transmitters
Comments on the article
The radio transmitter is a single-stage VHF FM transmitter operating in the broadcast frequency range of 61-73 MHz. The output power of the transmitter when using a 9-12V power supply is approximately 20 mW. It provides an information transmission range of about 150 m when using a receiver with a sensitivity of 10 μV.
(click to enlarge)
The modes of the UZCH transistors (VT1) and the RF generator (VT2) for direct current are set by resistors R3 and R4, respectively. The voltage of 1,2V on them and on the power supply of the microphone M1 falls from the parametric zener diode to R1, C1, VD1. Therefore, the device retains its performance when the supply voltage drops to 4-5V. In this case, a decrease in the output power of the device is observed, and the carrier frequency changes slightly.
The modulating amplifier is made on a transistor VT1 type KT315. The audio frequency voltage is supplied to its input from an electret microphone with an M1 amplifier of the MKE-3 type and the like. The amplified audio frequency voltage from the collector of the transistor VT1 is fed to the KV1A type VD109 varicap through a low-pass filter to resistor R5, capacitor C5 and resistor R7. The varicap VD1 is connected in series with the trimmer capacitor C8 in the emitter circuit of the transistor VT2. The oscillation frequency of the master oscillator, made on a transistor VT2 type KT315 (KT3102, KT368), is determined by the circuit elements L1, C6, C7 and the capacitance C8 and VD1.
Instead of the VD1 LED of the AL307 type, you can use any other LED or three diodes of the KD522 type and the like connected in series in the forward direction. The L1 coil is frameless, 8 mm in diameter, has 6 turns of PEV 0,8 wire.
When setting up the transmitter, tune in to a free section of the VHF FM band by compressing or stretching the turns of the coil L1 or by adjusting the capacitor C8. The frequency deviation is set by capacitor C8 according to the highest quality reception on the control receiver. The transmitter can also be tuned to the VHF FM broadcast range (88-108 MHz), for this it is necessary to reduce the number of turns L1 to 5 and the capacitance of the capacitor C6 and C7 to 10 pF. A piece of wire 60 cm long is used as an antenna. To reduce the influence of destabilizing factors, the antenna can be connected through a capacitor with a capacity of 1-2 pF.
See other articles Section Transmitters.
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 Soft robotics for agriculture
02.10.2021
"Soft" robots are made of malleable materials such as silicone and other polymers, rather than metal. These materials give the robots organic characteristics, replicating the work of muscles and allowing them to move and do work instead of a human that old metal machines can't.
A particular application of soft robotics that I was interested in was agriculture. Most automatic harvesting solutions only deal with large and hard crops. There are several mechanisms for picking smaller crops, but many are tough and can damage the plant in the process. Some success has come from companies such as Soft Robotics Inc, which have created grippers with soft features. But they were still only able to work with harder crops. These difficulties led to a research project in which I participated. The aim of the project was to explore the possibility of autonomous picking of light fragile berries, in particular raspberries. This task required a unique grip. Given the fragility of raspberries, this problem could be solved with the help of soft robotics.
The idea that arose was to create a tubular structure that would move towards the berry bush and separate each raspberry from its neighbors.
The end effector slides up the stem of the berry, after which the soft robotic bags come to work, which do not directly capture the fruit. Instead, they lightly press on the back of the berry, which connects to the plant's peduncle. Then the entire tube moves away, displacing the berry from the stem. It is similar to how a person pulls a berry with his fingers.
The innovations associated with the creation of robots that resemble the human body coincide with the development of the brain of robots. Advances in artificial intelligence are allowing machines to detect feelings like happiness and sadness in speech. Research is also focused on developing computer vision technologies that can detect emotions by analyzing facial expressions.
|
Other interesting news:
▪ A star with a unique magnetic field structure
▪ TV box Pipo X7
▪ The psychological state of the soldier will show a special marker
▪ wood-based nanofiber
▪ Mars was twice covered by oceans
News feed of science and technology, new electronics
Interesting materials of the Free Technical Library:
▪ section of the site Microphones, radio microphones. Article selection
▪ Article Cannon fodder. Popular expression
▪ article Which of the plant species has existed on the planet for the longest time? Detailed answer
▪ article Jasmine shrub. Legends, cultivation, methods of application
▪ article There is no alternative. Encyclopedia of radio electronics and electrical engineering
▪ SPST Chips: Maxim MAX4706 and MAX4707 Analog Switches. 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