Encyclopedia of radio electronics and electrical engineering / Civil radio communications

 Comments on the article

In the proposed article, an easy-to-use "software" way to connect the frequency grid in imported transceivers is considered.

Most of the mobile-base CB radio stations do not have a "Russian" frequency grid (it is 5 kHz lower than the "European" one). For this reason, they have to be modified using the software capabilities of the microprocessor [1] or by changing its clock frequency [2]. The latter method is used mainly for 40-channel transceivers (it is not considered in this publication).

A typical "software" refinement involves restarting the microprocessor after switching the outputs. For switching outputs, the existing control body is usually used, refusing its regular function, or an additional one is introduced. Reset occurs by turning off the radio and then turning it back on. In this case, the recharge of the internal memory of the microprocessor must be turned off.

Such a refinement is very simple, but the very procedure for accessing another frequency standard is too burdensome, since it consists of three (!) manipulations. Thus, the user, having once saved on revision, in the future constantly experiences annoying inconvenience when moving from "five" to "zero" and back.

The option developed by the author implements technical solutions that eliminate the routine, providing efficiency and comfort during work. The advantages of the proposed option are obvious. Switching from the European standard to the Russian one and vice versa is carried out simply and conveniently - from the PTT by simultaneously pressing the PTT ("Transmit") and DWN ("Down Channel Switching") buttons. The access time to another frequency standard is less than 0,5 s. A two-color LED indicator is provided (European standard - green glow, Russian - red). All functions of the radio station are preserved. The finishing technology is sparing (not a single printed conductor is cut). Available and cheap element base is used. The method can be applied to many radio stations.

When finalizing, a control module is installed in the transceiver, the conclusions of which are soldered to certain points on the board. The LED is placed on the front panel or in a light-protective box behind the LCD display.

The control module diagram is shown in fig. one.

On the elements VD1, VD2, R1, VT1, R2, a command decoder for switching frequency standards is assembled. Diode VD3. capacitor C1 and resistor R3 perform the function of protection against bounce buttons. Trigger DD1.1 captures the enabled mode. Key K1 switches the necessary outputs of the radio station processor in accordance with the selected mode. On the trigger DD1.2 and elements C2, R4, VD4, a single vibrator is assembled that generates a microprocessor reset pulse.

As an example, consider the operation of the module in conjunction with the popular radio station YOSAN JC-2204 (Fig. 2). In the receive mode, there is a voltage of +3,0 ... 3,8 V at the PTT and DWN inputs. Due to this, the transistor VT1 is open and its collector is low.

When you simultaneously press the PTT and DWN buttons on the PTT, both inputs close to a common wire, the VT1 transistor closes, and a high level appears on its collector. Separate pressing of the buttons does not affect the state of the device, and their simultaneous pressing does not lead to an emergency situation for the microprocessor of the radio station.

After passing the anti-bounce circuit, a positive voltage drop is supplied to the inputs C of the triggers DD1.1 and DD1.2. Trigger DD1.1 controls the key K1, which, in turn, carries out electronic switching of microprocessor outputs that activate the "Russian" frequency grid. In fact, the COM+ and COM- outputs are connected instead of an additional configuration diode installed during standard modification. Key K1 contains a field-effect n-channel transistor with an insulated gate, which provides good decoupling between the control and switching circuits. If the microprocessor outputs must be connected to a common wire (for example, in the ALAN-48 PLUS radio these are outputs 17 and 18), then it is advisable to assemble the key on a bipolar npn transistor (Fig. 3).

In this case, the conclusions 17 and 18 of the processor are combined and connected to the collector of the transistor VT1 (COM).

The two-color LED HL1 is connected to the direct and inverse outputs of the trigger DD1.1, therefore, with each switching of the trigger, the voltage on the indicator reverses the polarity, which ensures the emission of an alternately green or red glow of the indicator. Resistor R6 limits the output current of the microcircuit to a safe level.

Trigger DD1.2 is connected according to the single vibrator circuit and generates a rectangular pulse of positive polarity with a duration of 100 ms at the direct output to automatically reset the radio station's microprocessor. The pulse enters the base of the transistor VT2 and opens it. The RES pin goes low. The open transistor VT2 closes the base of the transistor Q606 to a common wire, it closes. In this case, the power supply of the microprocessor disappears for the duration of the pulse, ensuring its restart.

If necessary, you can give priority to the "European" grid when turning on the radio. To do this, you need to add the circuit for the initial installation of the trigger DD1.1 (Fig. 4).

Given the lack of free space inside the transceivers, small-sized radio elements should be used. The DD1 chip will completely replace the K564TM2 or K176TM2. Key K1 - KR1064KT1A, KR1064KT1V or a transistor of the KP501 series with letter indices A or B. VT1 and VT2 - any low-power npn transistors with a gain greater than 50. Diodes will fit any of the KD522, KD503, KD510, KD102, 1N4148 series. Capacitors - ceramic KM or imported analogues. Resistors - MLT or S2-33 with a power of 0,125 watts.

An imported two-color LED with two leads with a diameter of 1 mm LHG3 was used as the HL2092 indicator, but it will be replaced by domestic KIPD45, KIP18, KIP29. If a two-color three-pin ALC331A LED is available, then it can be turned on according to the diagram shown in fig. 5.

Finally, it is permissible to use any single-color LED, for example, AL307B (Fig. 6), but only the "Russian" grid will be displayed.

The design and technological design of the device depends on the topology of a particular radio station and the capabilities of the radio amateur. In the author's version, it is assembled by the surface mounting method and, after testing, it is filled with a compound in the form of a module with dimensions of 45x20x15 mm with flexible leads. This does not claim to be a record in miniaturization, however, it made it possible to install the module in a fairly compact YOSAN JC-2204 radio station. All the more problems will not arise if you use printed or surface mounting.

If serviceable parts are used, static electricity protection measures are observed, and the device is assembled and connected to the radio station without errors, it starts working immediately and does not need to be adjusted.

True, it is possible that the microprocessor will not have time to reset within 100 ms. Then you should use a capacitor C2 with a capacity of 0,22 ... 0,47 μF, which will increase the duration of the reset pulse and ensure the program starts correctly. But first you need to make sure that the microprocessor is not powered by bypassing the power stabilizer. Usually, companies remove the R635 SMD jumper for this.

But what if the construction and modes of the PTT and DWN / UP circuits differ from the circuit in Fig. 2? In this case, the switching of grids is organized using a non-fixed button for closing, installing it in a convenient place of the granciever. The best are imported buttons: clock SWT and miniature PSM. The button is connected to points A and B of the control module (see Fig. 1), while the elements VD1-VD3, VT1, R1, R2 must be excluded.

Literature

1. Gruzdev A. Expanding the capabilities of the radio station ALAN 48+. - Radio, 1998, No. 11, p. 61.
2. Efremov V. Introduction of the Russian Frequency Grid into Imported CB Radio Stations. - Radio, 1999, No. 9, p. 66.
3. Vinogradov Yu. Microphone headset for radio station YOSAN-2204. - Radio, 1999, No. 10, p. 61.
4. Mobile CB Transceiver JC-2204 /User's Manual/ Jaeil Engineering Co, Ltd.
5. Biryukov S. Digital devices based on MOS integrated circuits. - M.: Radio and communication, 1990.

Author: A.Sokolov, Moscow

See other articles Section Civil radio communications.

Read and write useful comments on this article.

<< Back

<< 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 Biochemical Reboot of the Eye: Treating Blindness 14.04.2017 Light-sensitive pigments, which are found in everyone from bacteria to vertebrates, can be reset by biomechanical manipulations and thereby restore people's vision. Scientists at the Western Reserve School of Medicine, USA have used a modified form of vitamin A to initiate a reset mechanism and restart the proteins needed for human vision. The target protein was photosensitive rhodopsin, which belongs to a family of proteins found in cell membranes that transmit an external signal to the internal cellular system. The discovery provides new opportunities for creating modified retinas that will improve vision. The discovery delves into the biochemistry of vision, to why the chemical configuration of the retina is important for human light perception. Humans see with the help of a highly sensitive protein, rhodopsin, which attaches to retinal molecules to sense light. Photons of light enter the eye and are absorbed by the retinal-rhodopsin complex, activating the downstream signaling cascade that makes up vision. It is especially important that the retina waits for light in one chemical configuration, and after absorption it changes into another one called all-trans retinal. But this transformation is unidirectional, and many specialized proteins are needed to return the retina to its first configuration. Inherited mutations in any of these can cause degenerative retinal diseases. Researchers who want to cure such diseases must either correct or bypass the altered proteins. Researchers have discovered a self-renewing mechanism in bovine rhodopsin that is extremely similar to human. They used the purified proteins in the lab to show how their modified retina binds to bovine rhodopsin, successfully activates human proteins when exposed to light, and after signaling with thermal energy alone, slowly reverts to an inactive form that can be reactivated by photons. The discovery suggests that retinal molecules with a specific chemical structure can stimulate rhodopsin, which is needed for human vision, which means that mutated proteins can be bypassed and restore people's vision.

Other interesting news:

▪ Charger for electric car 1 km per second

▪ Hamster sleeps - telomeres grow

▪ migraine pills cause migraines

▪ The tablet will be able to control an unmanned truck

▪ Inflatable braking device in a backpack

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ Telephony site section. Article selection

▪ article How and when should I clean my VCR? video art

▪ How do condensation bands form? Detailed answer

▪ Helleborus article. Legends, cultivation, methods of application

▪ article Electronic massage therapist. Encyclopedia of radio electronics and electrical engineering

▪ article Rainbow without sun. Chemical experience

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

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

www.diagram.com.ua
2000-2024