A simple VHF-FM radio station. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Civil radio communications
Comments on the article
The advantages of this design are simplicity, repeatability and availability of the element base. The radio station is designed for two-way communication using frequency modulation.
A superregenerator with a relatively high sensitivity of 10 μV was used as a receiver.
The superregenerative detector of the receiver is made on the transistor VT2, and the highly sensitive ULF is made on the transistors VT3, VT4. The circuit lacks quartz, coils with taps, and a low-frequency transformer, which increases the availability of repeating it even for beginner radio amateurs.
(click to enlarge)
Establishing a radio station is also not difficult. To do this, a tuning resistor R4 is installed on the receiver board. By rotating the slider of this resistor, a stable "super" noise is achieved when the transmitter of another radio station is turned on. Sometimes it is necessary to select the capacitance of the capacitor C3 for the stability of the superregenerative detector, for which it is necessary to temporarily place the same trimmer in parallel with it as in the circuits.
For final tuning, both radio stations are located at a distance of 5-10 meters from each other. They must have antennas with which they will be operated in the future.
By tuning the loop capacitors of the receiver (C11) of one radio station and the transmitter (C3) of another radio station, noticeable noise suppression in the receiver phones is achieved. If this fails, then it is necessary to slightly stretch or compress the turns of the coils L1 and L2, then repeat the tuning using trimmer capacitors.
Speaking words into the transmitter microphone, the receiver circuit capacitor is adjusted to the highest reception volume and speech intelligibility through telephones. It is recommended that you speak while holding the microphone close to your mouth.
Then, increasing the distance between the radio stations, the tuning according to the method is repeated several times.
Setting up the transmitter, as a rule, is usually not required, because with proper assembly, the oscillator starts working immediately. To verify this, you can assemble the simplest RF probe, the circuit of which is shown in Fig. 2.
During normal operation of the radio, the RF voltage at points 1,2 and 3 should be as low as possible (controlled by the RF probe).
With batteries of 4,5 V cells, with an antenna length of 20-25 cm, a fairly stable connection is established up to 200 meters. This distance can be greatly increased by using 9V batteries and longer antennas.
The radio station uses DP-0,1 chokes with an inductance of 40-120 μH. Coils L1 and L2 are the same, frameless, contain six turns of a 0,9 mm copper passage. Winding diameter - 8 mm, length - 12 mm.
Transistors VT1 and VT2 can be replaced with P423 or GT313.
Literature:
- Wireless pickup. Radio.-1971.- No. 11. - P.60.
- Putyatin N. Receiver-controller. Radio. - 1970.- No. 3. - S.53-55.
Author: V. Artemenko, Kiev; Publication: N. Bolshakov, rf.atnn.ru
See other articles Section Civil radio communications.
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 Notebooks Honor MagicBook X
15.05.2021
Honor has officially unveiled new thin, light and compact laptops enclosed in metal cases - MagicBook X14 and MagicBook X15. The first has a thickness of 15,9 millimeters and a weight of 1,38 kilograms, the second - 16,9 millimeters and 1,56 kilograms.
As you might guess from the names, the MagicBook X14 has a 14-inch screen, while the MagicBook X15 has a 15,6-inch one. The resolution of the matrix in both cases is 1920 x 1080 pixels (Full HD). The base version of the MagicBook X14 has a Core i3-10110U processor, 8GB of RAM and a 256GB SSD. The top version is Core i5-10210U, 16/512 GB. Prices for early buyers are $465 and $620, respectively.
The base version of the MagicBook X15 received similar specifications and was priced at $480. The top one received the same as the older configuration, the X14 Core i5-10210U processor, but only 8 GB of RAM. It is valued at $555.
|
Other interesting news:
▪ Samsung Full Solid State Battery
▪ Beware of moonlight
▪ Moisture-resistant and dustproof reader PocketBook 640
▪ diamond diode
▪ Economical hybrid motorcycle
News feed of science and technology, new electronics
Interesting materials of the Free Technical Library:
▪ section of the site Mobile communications. Article selection
▪ article About time and about myself. Popular expression
▪ article How many elementary particles are known now? Detailed answer
▪ article Locksmith for the repair and maintenance of electrical equipment of tractors. Standard instruction on labor protection
▪ article Radio bug detector with a linear scale of eight LEDs. Encyclopedia of radio electronics and electrical engineering
▪ article Improvement of the detector receiver. 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