Menu English Ukrainian russian Home

Free technical library for hobbyists and professionals Free technical library

Free library / Schemes of radio-electronic and electrical devices

Standby mode in the CB radio station. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Civil radio communications

Comments on the article Comments on the article

All users of the civilian range know how much inconvenience delivers long-range travel. Especially when it comes to business communications. The use of radio stations in such conditions becomes simply not possible, as it forces your correspondent to turn the squelch up to the stop or even turn off the volume. Yes, and in a clean air, not everyone wants to listen to the conversations of radio amateurs on your duty frequency. In order to get away from these troubles, paging systems using the DTMF code are used. But this is not available to everyone - both due to the cost and due to the lack of an element base.

I propose a simple device scheme available for repetition by almost every radio amateur, built on cheap affordable elements. This design has been used for several years in many radio stations and has worked flawlessly.

The device works on the principle of selective calling and performs the following functions:

1. Securely blocks the station on reception in the absence of a call.
2. Opens the station when there is a call signal, regardless of the position of the SHP knob.
3. Automatically switches the station to normal operating mode at the start of communication.
4. Automatically transfers the station to standby mode at the end of communication, after 20-30 seconds, which does not require any additional actions from the operator.
5. There is a switch to the normal mode, but the function of turning off the SHB with a call signal is preserved, which allows you not to miss it if the connection is not sure.

The device (Fig. 1) is made on a single K561LN2 chip, consisting of six logic elements.

Standby mode in the CB radio station. Scheme
Fig.1 (click to enlarge)

The operation of the circuit is very simple. The low-frequency signal taken from the detector (simpler than the upper end of the volume control) is fed to the DD1.1 limiter amplifier, then to the DD1.2 resonant amplifier, the DD1.3 threshold device (which generates pulses when a 1400 Hz tone signal appears), inverter DD1.4, through the integrator of positive pulses to the inverter DD1.6, which blocks the station's squelch. To do this, output 3 of the device is connected to the base of the transistor switch in the station, which controls the squelch. From the DD1.5 inverter, a positive potential for prohibiting the opening of the SR in the initial position is also supplied there. The barring signal is removed when the call goes through and after pressing the transfer. To do this, pin 2 is connected to the station at the point of appearance + when transmitting.

To make a call, a conventional multivibrator at 1400 Hz, controlled by a button, is built into the station, the output of which is connected through a 100 KΩ resistor to the signal circuit of the microphone path.

Author: Alexander Shatun, Dergachi, Kharkiv region; Publication: N. Bolshakov,

See other articles Section Civil radio communications.

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

Digital home through the eyes of the people 30.10.2005

According to Accenture research, the cost and complexity of high-tech devices is discouraging consumers from making their homes "digital". In addition, potential buyers are very worried about the problems associated with the launch of a single home system.

Of the 2600 respondents (British), 70% wished that the task of combining devices together was solved by one company, although many companies just undertake to solve the problem partially. 80% of respondents said that it is unrealistic to raise money to buy all the devices.

According to the results of the study, it was possible to determine what types of "digital homes" are in demand. 42% want a home entertainment system. 37% chose the home system for health care, and the least popular was the idea of ​​a "digital home" in the form of a virtual office or some system that organizes the user's life and work - 28%.

When asked why they need additional "gadgets" at home, 56% of respondents answered that it would help save money, 46% said that it would make their life easier, and 34% decided that being at home with electronic products would be much more fun.

When asked about the perceived negative side of such "electronization", 40% suggested that it could affect their privacy and security, and 33% of people are worried about the rapid "moral" obsolescence of technology.

Other interesting news:

▪ MOTOROLA FV500AA Compact Radio

▪ Gadgets before bed are harmful to health

▪ PCI7621 Flash Media Speed ​​Controller

▪ Grasshopper robot

▪ Doubling the capacitance of supercapacitors

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site for the radio amateur-designer. Article selection

▪ article Leontiev Vasily. Biography of a scientist

▪ article How are English wages related to salt? Detailed answer

▪ Article Leading Sales Manager. Job description

▪ article Photovoltaic systems with generators. Encyclopedia of radio electronics and electrical engineering

▪ article The appearance of the card in the desired pile. Focus secret

Leave your comment on this article:


Email (optional):

A comment:

All languages ​​of this page

Home page | Library | Articles | Website map | Site Reviews