- MEMBERS OF LPŻ (League of Friends of a Soldier) AT LENINGRAD'S COMPETITION - M. Konieczny (1)
"On November 12 last year, a team of Elpetrators flew from Warsaw to Leningrad for the International Radiotelegraphist Competition, which took place on November 18-26. The team consisted of six players and three management..."
General view of the competition hall - Reception competition with manual registration.
- IMPLEMENTATION OF THE TRAINING OPERATION PLAN FOR LPŻ (League of Friends of a Soldier) - M. Rybak (3)
"The planned economy provides us with a rapid increase in the country's industrialization and agricultural production, intensive reconstruction of the damage, dissemination of science, inflow of qualified personnel and many other achievements. The full-time employees and social activists of the LPŻ Voivodship Boards are generally aware of the importance of the full implementation of the training plan and the preparation of new communication personnel for the needs of the national economy and national defense..."
- CONDENSER MICROPHONE - A. Musioł (4)
"A condenser microphone occupies one of the first places in electroacoustics, mainly due to its electrical properties and simple construction. It not only has an even frequency response in the range of 50 ÷ 10,000 Hz, but also introduces almost no non-linear distortions and practically has no sensitivity threshold. The noise level is determined only by the noise from the tubes and individual parts of the amplifier. Simplicity in construction, insensitivity to shocks, are the advantages that predestine a condenser microphone for use by radio amateurs, especially when it comes to obtaining high-quality sound reproduction, e.g. in megaphonization and reporting. Even the simplest types of microphones give satisfactory results, of course, provided that they are carefully made and important design principles are followed. The only disadvantage of the mentioned microphone is that, due to the need to reduce the input capacity, it requires a preamplifier located as close as possible to the microphone insert itself. It is advisable to place the microphone and the preamplifier in one common metal housing..."
Condenser microphone design
Two-stage microphone preamplifier based on subminiature battery tubes type CK506AX (or DL67)
- RADIO AT THE LIPBIAN FAIR - K. L. (9)
"This year's Leipzig Trade Fair has probably broken all records so far in terms of the number of exhibitors, attendance of visitors, concluded commercial transactions and exhibition space occupied. Representatives of many countries took part as exhibitors. A large radio pavilion gave an overview of the achievements of the GDR in the field of radio engineering..."
- RECEIVER OF ADVANCED SHORTWARD (part II) - W. Nietyksza SP5FM (10)
"The heptode part of the ECH21 tube works as an intermediate frequency amplifier of 85 kHz. The voltage RW is also applied to it. The screen is powered by a 47 kΩ resistor and blocked for high frequency. with a 50 T pF capacitor. In the anode there is a filter similar to the previous one. with adjustable feedback..."
- FIVE BANDS WITHOUT SWITCH - Z. Bieńkowski SP7LB (12)
"The normally used anode circuit allows the final stage to be tuned within relatively small limits. If C is an ordinary rotary capacitor with capacities Cmax - 450 pF and Cmin - 10 pF, and the assumed mounting capacity together with the output of the lamp Cdod - 40 pF..."
- RESULTS OF THE INTERNATIONAL SHORT WAVE COMPETITION ON THE ANNIVERSARY OF A. POPOW'S DEATH (15)
"We present the results of the International Amateur Radio Competition, organized by the Central Radio Club DOSAAF on May 9, 1954, to commemorate the 59th anniversary of the death of the brilliant Russian scientist, the inventor of radio - Alexander Popov..."
- "HELVETIA 22" COMPETITION IN 1955 (16)
"Following the tradition of previous years, the association of Swiss radio amateurs USKA is organizing the international competition "Helvetia 22" this year. The competition will start on March 19, 1955 at 15.00 GMT and will end on March 20, 1955 at 17.00 GMT..."
- PERMANENT COMPETITION OF SENDERS AND LISTENERS "SWNN" (17)
"In order to raise technical and operator qualifications as well as increase and demonstrate the achievements of Polish hams on a national and international scale - the Central Communications Club of the League of Friends of the Soldier organizes a constant competition between broadcasters and listeners from the People's Republic of Poland..."
- FROM THE LIFE OF THE LPŻ (League of Friends of a Soldier) COMMUNICATIONS SECTION IN RZESZÓW - S. Kopeć (18)
"In connection with the establishment of the LPŻ Communications Section at the Communication Equipment Factory in Rzeszów, I would like to share with the Readers of RADIOAMATOR some of my observations from the Section's work..."
- ON AMATEUR BANDS (18)
- ON THE SELECTION OF HF CIRCUITS ELEMENTS IN A SUPERHETERODYNE RECEIVER - mgr inż. Z. Kachlicki SP3KP (19)
"As you know, superheteodyne receivers work on the principle of frequency conversion. Unlike direct amplification receivers, they are equipped with a mixer and a local oscillator..."
- GROUP SOUND SOURCES - inż. J. Bartkiewicz (23)
"When sounding large rooms or open spaces, a number of issues are encountered that do not occur in other types of operation of electroacoustic devices. In practice, we distinguish 3 sound systems, namely: decentralized, central, and mixed..."
- CALCULATION OF COILS ON FERROMAGNETIC CORES (28)
"Radio amateurs often have various types of high frequency cores, the use of which is quite difficult due to the ignorance of the magnetic properties of the individual cores..."
- WE BUILD OUR OWN SOLDERING IRON (28)
"The electric soldering flask necessary for the needs of radio amateurs does not necessarily have to be purchased as a finished factory product. We can make it ourselves, based on the description below..."
- ADVICES (30)
"Which may be the reason for the complete lack of reception on the shortwave range in the Pionier U2 receiver. How a program from a Mazur receiver can be mixed with reception from a phono adapter. Is it possible to have and use a device for playing music remotely, made as described in the RADIOAMATOR?.."
- EXCHANGE (30)
- NOMOGRAM: CALCULATION OF LOW POWER GRID TRANSFORMER (31)
"In their practice, radio amateurs, very often due to the lack of appropriate transformers on the market, use their cores and make the necessary transformers on their own. In order to design the transformer, it is necessary to make preliminary calculations that will determine the core cross-section, number of turns, wire thickness, etc. To make it easier, we present a nomogram below, which allows you to quickly determine these values with sufficient accuracy..."
PDF : Radioamator 1955/01 v1