A simple VHF receiver. Scheme, description

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

A simple VHF receiver. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / radio reception

Comments on the article

The proposed simple VHF receiver is assembled on the basis of the domestic chip KR174XA34. It works in the "Soviet" range of 65,0. ..74,6 MHz. Reception is carried out on a whip telescopic antenna.

(click to enlarge)

Resistor R1 - type MLT-0,5. Its parasitic capacitance cuts frequencies above the received range. Coil L1 is 1 turn (ring) of a mounting stranded wire 00,15 ... 0,3 mm. Ring diameter - 8...10 mm. Coil l_2 contains 5 turns of wire PEV-2 00.3.. .0.4 mm. wound on a mandrel (handle) 06.. .7 mm. The coil removed from the mandrel is carefully mounted on the board. Trimmer capacitor C14 - KT-21 L3-type choke DP with an inductance of 80 ... 120 μH - taken from an old TV (III. IV or V generation). Variable resistors R7. R9 - SPZ-4. For smoother volume control, R7 must be with a functional characteristic "B".

To work in the "bourgeois" range of 87,5 ... 108 MHz, the L2 coil has 4 turns of the same wire, and the capacitance C14 is 2 ... 10 pF.

The tuning resistor R9 works as a voltage divider for the Zener diode VD2. From the R9 engine through the R6-C19 filter circuit, a voltage of 1 ... 0.1 V is supplied to the VD3,3 varicap. When this voltage changes, the varicap capacitance changes, reorganizing the L2-C14-C16-Cvd1 circuit in frequency. For ease of adjustment, it is worth putting a large-diameter knob with a scale on the R9 axis.

With serviceable parts and proper installation, the receiver starts working immediately. The adjustment comes down to laying the range with elements C14 and L2. Carefully squeezing and unclenching the turns of L2, we change its inductance and. respectively, the tuning frequency. After the final adjustment of the range, it is desirable to fill the coil with melted wax.

For rural areas, the capacitance of C8 can be increased to 680 pF. In a city with an abundance of industrial interference C8, it is better to take 15 ... 20 pF.

Author: A. Litvinenko, Slavyansk-on-Kuban, Krasnodar region.

See other articles Section radio reception.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive

Baseus D03 Wireless Over-Ear Headphones 23.06.2023

The Baseus brand has introduced its new model of Baseus D03 wireless full-size headphones, which have expanded their range of audio devices.

The Baseus D03 headphones feature an adjustable metal headband and comfortable soft ear cushions that rotate 95 degrees for optimal comfort in a variety of situations. The multifunctional buttons are located on one side of the headphones.

These headphones are equipped with 40mm dynamic drivers, support low latency mode with a binary delay of 0,08 seconds, and also have Bluetooth 5.3 with a range of up to 10 meters. They also have a 3,5mm audio jack for wired connectivity.

Baseus D03 headphones are powered by a built-in 300 mAh battery that provides up to 30 hours of battery life. The earbuds are charged via the USB-C port.

In China, the cost of Baseus D03 headphones is only $16. They are available in black, white and grey, offering a variety of choices for consumers.

Other interesting news:

▪ Robot muscle hydrogel

▪ High-voltage ultra-bright LED drivers from IR

▪ Sauna for the heart

▪ Data transmission using fast neutrons

▪ Three-dimensional image on the monitor screen

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Funny puzzles. Article selection

▪ article Modernized shovel. Drawing, description

▪ Article Is It Good to Think? Detailed answer

▪ article Head of the regime-secret department. Job description

▪ article Class A ultralinear amplifier. Encyclopedia of radio electronics and electrical engineering

▪ article Homemade UPS for imported transceiver. 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