Improvement of transceivers Alan 48 Plus and Alan 78 Plus. Scheme, description

Free technical library

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

Improvement of transceivers Alan 48 Plus and Alan 78 Plus. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Civil radio communications

Comments on the article

Radio stations Alan 48 Plus and Alan 78 Plus are widely used among CBS users. Various ways of introducing the "Russian" frequency grid into these devices are described in detail in [1,2]. If the first method (and its varieties) is easy to implement, but inconvenient to use, then the second, on the contrary, is comfortable to use, but more difficult, therefore, it can be recommended for repetition only by trained radio amateurs.

With this in mind, a method was developed that combines the advantages of the first two. Possessing circuitry simplicity (only three radio components are introduced into the transceiver), the proposed option provides a choice of "0/-5 kHz" grids at the touch of a button and without turning off the power. This procedure is ergonomic and does not consume the operating life of the "POWER / VOLUME" control (deficient variable resistor with a switch). The revision is applicable to Alan transceivers with a microprocessor marked "MAXON 2204446-A".

Modification of the transceiver consists in installing a module, the scheme of which is shown in the figure, and changing the switching of the "EMG" button. When the radio is turned on, the transistor VT1 opens 50 ... 100 ms after the supply voltage of the microprocessor is +5 V. The necessary delay is provided by the integrating circuit R1C1. Thus, when initializing (starting) the processor, there is a high level at its pins 17 and 18 (SELECT PROGRAMM) and the transceiver is configured into the "European" frequency grid.

Refinement of transceivers Alan 48 Plus and Alan 78 Plus

To switch to the "Russian" grid, you must press and quickly release the SB1 button. In this case, the output 68 of the microprocessor (RESET CPU) closes to a common wire and the processor restarts. Since when the button is pressed briefly, the capacitor C1 does not have time to discharge through the resistor R1, the transistor VT1 is held open. Thus, when the processor is restarted, its outputs 17, 18 remain low and the transceiver is configured into the "Russian" grid.

To return to the "European" grid, you need to hold down the SB1 button for approximately 1 s. In this case, the capacitor C1 is completely discharged and when the button is released, a process similar to that which occurs when the transceiver is first turned on is reproduced.

Capacitor C1 is better to use ceramic or tantalum for surface mounting. The field effect transistor KP501A can be replaced with a current key KR1014KT1 with the letter index A or B (preferably in the TO-92 package).

Module elements are mounted in the smallest possible volume and filled with compound. After machining, the shape of the module imitates a microcircuit with three hard leads. Other types of mounting are also acceptable, up to the hinged soldering on the transceiver printed circuit board.

Literature

Gruzdev A. Expanding the capabilities of the radio station ALAN 48+. - Radio, 1998, No. 11, p. 61.
Sokolov A. "Russian" grid in C-B radio station. - Radio, 2000, No. 9, p. 64.

Author: A.Sokolov, Moscow

See other articles Section Civil radio communications.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive

Individual beacon to rescue the victim 21.11.2002

In the United States, the "Sea Marshall" device, designed for individual rescue in emergency situations, such as an accident at sea, went on sale.

A beacon weighing about 150 grams and the size of a pack of cigarettes is hung around the neck, for which there is a flexible transparent tube, which is a bright electroluminescent lamp. To report a distress signal on the international frequency of 121,5 MHz, the user of the device just needs to press a button. The beacon also turns on from contact with water for 20 s.

An ordinary lithium battery with a voltage of 9 V is enough for 20...30 hours of continuous operation of the beacon. The device costs about 170 USD.

Other interesting news:

▪ Children's shoes with a GPS tracker

▪ Solar panels on indium phosphide

▪ Robot grower

▪ Print meat in space

▪ ICL5102 - Efficient half-bridge AC-DC converter controller with PFC

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ website section Television. Article selection

▪ article Open society. Popular expression

▪ article How do we know what dinosaurs looked like? Detailed answer

▪ article White mustard. Legends, cultivation, methods of application