Author: Petrosani Children's Club
Quarterly magazine of the circle of electronic constructions and amateur radio
Coordinator: Prof. Kovacs Imre - YO2LTF
Did you know that ...? The origin of the Handy-Talky transceiver station, used during the Korean War and the Vietnam War, bears the American code RT-196 PRC-6? Designed in 1945 to replace the BC-611, it is equipped with 13 miniature tubes, for HF and FM power in the 47-55,4 Mhz band of 200mW.
The structure of the magazine
1. Ham-spirit (Code of conduct of the amateur radio)
Traffic amateurs from all countries of the world must technically comply with national and international radio regulations.
The exchanges of messages - through the air - take place between partners of all ethnicities and social strata - from students to dignitaries - and imperatively requires a dignified, cultured and civilized attitude, both in the code of QSOs and in daily activity.
Taking into account the above, a guide, or rather a "code of conduct" of the traffic radio amateur has been prepared since 1929 by the amateur radio Paul M. Segal-W9EEA...
2. DIY phone
The presented device allows a conversation between two people, who are at a maximum distance 500m.
The electrical diagram is composed of 3 elements:
a) Speaker (8 - 200 Ohm, 0,25 w);
b) Electrical circuit (insulated copper wire with enamel or plastic with a diameter of 0,3 - 0,5 mm);
3. Aluminum / air electrical source
The electrical source shown can be built with materials that exist in the kitchen. Its operating principle consists in transformation of chemical energy into electricity.
The source uses oxygen from the air as a depolarizer. The reaction of combining hydrogen with oxygen in the air takes place in the pores of the carbon pellet resulting in water.. The resulting electrical voltage produces an electric current of approx. 10 mA that is capable of lighting a red LED.
Materials needed to build this source:
a) Cooking salt (NaCl);
b) Water (H2O);
c) Aluminum sheet (Al);
d) Medicinal charcoal (C);
e) Paper napkin.
4. About voltage regulators (from the series: 78xxx and 79xxx)
Series regulators 78xxx are positive voltage regulators, those in the series 79xxx are of negative voltage. The unstabilized input voltage is applied to the "V +" or "V-" terminal and the stabilized voltage is "collected" from the "V out" terminal.
- Regulatory protections;
- Boost Regulator;
- Power regulator;
- Changing the output voltage;
- Constant current generator;
- Neutral mass supply (without galvanic separation);
- Symmetrical voltage regulator;
- Current limiter ..
5. Antenna and grounding (rules extracted from NTS)
4.1. Anchored pillars can be installed on the roofs of buildings, up to 8 m high. Pillars with a higher height can be installed only with the approval of the bodies that have the quality to give such approvals.
4.2. Pillar anchors installed on the roofs of buildings must be attached to hooks or rings screwed into the roof beams or walls of houses. It is forbidden to tie anchors and pillars to chimneys, lighting lanterns, etc.
4.3. The suspension of the antennas above the conductors of the lighting network and of the radio lines is allowed only if these conductors are isolated, have a position perpendicular to the direction of the antenna and are at a distance of at least 4 m from them. Suspension of antennas above the streets with electric traction installation, above or below the conductors of voltage lines above 1000 V is prohibited.
4.4. People working on the roof will take all necessary safety measures to prevent falls. Seat belts of at least 12 mm in diameter shall be used. It is forbidden to work during frost.
4.5. On the power supply wires of the transmitting and receiving antennas will be mounted earthing switches and tipping screws of the tip type. During lightning storms, antenna feeders will connect to ground.
4.6. The ground sockets will be of the artificial, tubular or radial type. For their realization will be used steel pipes or flat strips. The electrical resistance of the ground sockets will be less than 4 ohms. If it is impossible to make an artificial grounding, it will be possible to use water supply pipes for this purpose, provided that it is checked whether the connection between the pipes is electrically ensured and the electrical resistance is low.
4.7. The connection with the earth socket will be made with conductors as short as possible that will be welded or tinned. If tinning is used, the solders will be covered with melted tar. The grounded conductors can be made of copper or iron. The minimum section of copper conductors will be 12 mm square. The iron conductors will have a larger section than the copper ones.
4.8. The connections with the grounding and its electrical resistance will be checked at least twice a year.
6. Semiconductor marking codes
- European semiconductor marking codes;
- Japanese semiconductor marking codes (transistors 2SXXX);
7. Military receivers and transmitters
- BC-603 receiver;
- BC-728 receiver;
- Aviation Transmitter-Receiver SARAM 5-52;
- Aviation transmitter-receiver SOCRAT ER74A;
- Handy Talky AN / PRC-6;
- TS-153 / AP field meter.
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