Radioamator, Volume IV, May 1954, No. 5.
CONTENT OF THE NUMBER (2nd cover page)
COMPETITION (cover page 2)
According to the announcement in the previous issue of RADIOAMATOR, we inform interested Readers of the details regarding the end of our competition. Thus:
- Competition participants should present their models of receivers at the CENTRAL LOCATION OF THE LPŻ CLUB in WARSAW, 17 MOKOTOWSKA Street, on 13 JUNE this year. (this is Sunday) at 10 am.
- It is desirable that the models presented for evaluation are equipped with their own power sources. Each model should be accompanied by its schematic diagram and a list of components (types of tubes, number and values of capacitors, resistances, etc.).
- The description of the awarded works will be published in the RADIOAMATOR magazine.
Labour Day (1)
May 1, 1890. The first Festival of international solidarity of the working masses, celebrated by the Polish proletariat in the gloomy years of slavery and exploitation. The first holiday, and at the same time a symbol of the relentless struggle of the working class for national and social liberation. The red of the banners, hooks and bayonets of the tsarist cordons, then the clubs and bullets of the Sanacja cones, the red of the blood shed during the May Day parades. The heroic, steadfast attitude of those who, as the vanguard of future revolutionary movements, sacrificed themselves to fight slavery and exploitation, for the right to work and another life, for social justice.
May 1, 1954. The sixty-fifth, May 1st, World Labor Day, celebrated for the tenth time in People's Poland by the entire nation led by the heroic working class.
Radio Day (2)
May 7 was entered into the history of technology as a memorable date when radio was born. The motherland of the Great October Revolution became the cradle of this epochal invention, where the date of May 7 was also announced as "Radio Day".
This year is the fiftieth consecutive anniversary of the practical implementation of the radio, an event that made a considerable revolution in technology and progress.
Every year, on May 7, the entire radio family of the Soviet Union and the countries of people's democracy returns to the modest figure of the great Russian scientist, creator of the world's first radio receiver and pioneer of radio technology, A. S. Popov.
The People's Government ensures the development of professional company libraries (3)
We would like to draw your attention to the important Government Resolution concerning company professional libraries. In Monitor Polski no. A-94 of October 16, 1953, it was announced under item 1306 Resolution of the Presidium of the Government No. 897 of September 24, 1953 on the development of the network of professional company libraries...
Vocational radio engineering education (4)
- General information.
In the letters addressed to the RADIOAMATOR magazine, many readers of our monthly ask about the possibilities of training in radio engineering, what schools train young people to the profession of radio technician, are there any radio engineering courses for beginners - for example by correspondence...
An excerpt from an exercise in the radio engineering workshop of the Warsaw Radiocommunication Technical School.
- A visit to the Radiocommunication Technical College.
The building of the Main Post Office in Warsaw houses the Radiocommunication Technical School, which trains future radio technicians. As this school is of interest to our young readers, we visited it.
Classes begin. At one table, the frequency is measured by the beat method using two generators. A superheterodyne system was set up on another table. Students view the graph of the resonance curves on an oscilloscope.
The characteristics of electron tubes are investigated nearby.
Future radio technicians work in silence and concentration. In a few years they will take up responsible positions in radio stations, in radio stations, in radio equipment factories.
The road to the University of Technology is also open for them, where at the communications department they can deepen and expand their knowledge. Our youth in People's Poland has such broad prospects of study and professional work as never before.
It would seem that picking up the characteristics of electron tubes is very complicated. As you can see, however, girls can do it perfectly well.
Military radio stations help in training soldiers (6)
Thanks to the caring care of the Party, the Government and the Military Command, as well as the comprehensive development of soldiers, military units were equipped with their own radio equipment.
Radio broadcasts today occupy an important place in the life of the army, in the entire system of political, military and cultural education of soldiers. Military radio stations play a great role in propaganda and agitation work, in raising the level of awareness of soldiers and in mobilizing them to new achievements in the field of military and political training.
Our readers write (7)
FROM THE LIFE OF AMATEUR RADIO - Low frequency amplifier in the radio ham receiver (8)
Every radio amateur - broadcaster strives to have the most selective receiver possible. There are many reasons for this. The number of amateur stations in the world is currently over one hundred thousand, so that often several hundred stations operate simultaneously in the 100 kc / s bandwidth. The "Piston" is thus indescribable, and it is magnified by the presence of unwanted signals in the bands. At the same time, in the present period of minimum sunspots, the signals from distant stations are usually very weak and jammed by a large number of European stations. So, if we want to get good results, we must have an extremely selective receiver, the more so as with increasing selectivity the level of noise and crackling decreases. Top-class factory receivers usually have to remain only in the sphere of dreams of an amateur who tries to achieve the best possible effect with his own, usually very modest means.
It is therefore worth knowing that by using a selective low-frequency amplifier, we can even obtain a selectivity not worse when receiving telegraphy in an ordinary 0-V-1 or 2-V-1 than in an expensive factory multi-tube receiver....
...We will just start with the simple circuits from Figures 1a and 1b.
... The last type of low frequency filter discussed here (although there are more) can be seen in Figure "selectoject". It is built of two resistive-capacitive phase shifters...
... Finally, in Figure 7 we see some modification of the "selectoject". important, however, only for "telegraphists"...
AMATEUR TELEVISION CENTER IN GORKY (10)
Last year, Soviet radio amateurs launched a television center in Gorki, second after Kharkiv.
144 Mc / s transmitter with quartz stabilization (11)
The ultra-shortwave single-stage self-excited transmitters initially used by Polish broadcasters - usually with a circuit with fixed distributed - had many disadvantages. The main one was the low stability and detrimental side frequency modulation resulting from the mesh or anode modulation of such an oscillator. Much better results are provided by a two- or three-stage transmitter, in which we modulate not the oscillator, but the power amplifier.
Diagram of the transmitter.
Bottom view of the chassis. Horizontally mounted circuit coil at 48 Mc / s.
The front panel of the transmitter.
Top view of the transmitter. From left to right: terminating stage circuit, LD15 electron tube, quartz in socket, oscillator tubes and first doubler.
Ultra-shortwave antennas (13)
From the history of amateur radio - Saved thanks to listening to amateur ham radio (15)
On May 22, 1928, at 4.30 p.m., the Italian airship "Italia" took a flight towards the North Pole, carrying on its deck a polar scientific expedition led by General Nobile.
On amateur bands (16)
We are only four years away from the highest sunspot activity that will occur in 1958.
Instrument for detecting line faults (16)
Various types of measuring devices are used to detect faults (short circuits, breaks, bad contact) on telephone lines.
LET'S LEARN RADIO TECHNOLOGY - Systems with negative feedback (17)
The previous article discussed the advantages of using negative feedback in repeater circuits.
Overview of diagrams - Radio receiver "Dorożnyj" (20)
This year in the USSR, mass production of the "Dorożny" portable receiver (suitcase) began.
Schematic diagram of the "Dorożny" receiver.
Detector receiver "Komsomolec" (22)
Among the detector receivers, the "Komsomolec" detector receiver enjoys the greatest recognition in the Soviet Union..
The Amateur Television Set (Eighth Part) (24)
When we start describing the visual part of a television set, we will briefly consider the essential elements it must consist of..
Fig. 2. An example of changes in the video signal voltage within the analysis of one line (the photo shows the analyzed line with a thick line).
OHS in amateur radio practice (28)
- Installing external receiving antennas and grounding.
- Use of a light antenna.
- Charging the batteries.
A.G. Stoletow - discoverer of the photoelectric phenomenon (29)
This year, it has been 65 years since Alexander Grigoriewicz Stoletow discovered the photoelectric phenomenon, which is of great importance in the development of television.
Diagram of an experimental device by A. G. Stoletow.
The apparatus, the schematic diagram of which is shown in Figure 208 in the monthly RADIOAMATOR No. 1 from 1952, with proper installation and well-made coil assemblies - can provide a very good reception.
New releases (31)
Radio communication devices with design - antenna devices. W. Lisicki. Wydawnictwa Komunikacyjne, Warsaw 1954. Pages 355, circulation of 3000 copies, price PLN 13.50.
INTERNATIONAL SHORT WAVE COMPETITIONS OF PEOPLE DEMOCRACY COUNTRIES (31)
On the initiative of DOSAAF (Brotherhood Organization of the LPŻ in the USSR), on May 9 this year amateur radio competition.
Do you know that ... (cover page 3)
The International Race for Peace is undoubtedly the world's largest amateur cycling event. The radio communication of the Race, organized and operated by Polish amateurs of short waves....
Survey (cover page 4)
The monthly RADIOAMATOR - dedicated to popularizing radio knowledge and promoting the creativity of radio amateurs among the broad masses of society - has won over a large crowd of regular readers, as well as numerous friends and correspondents (both belonging to the LPŻ organization and not affiliated with it)...