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Encyclopedia of radio electronics and electrical engineering / Ham Radio Technologies

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To connect the power source to the transistor receiver or amplifier, you can use the terminal block from the Krona battery.

Installing transistors at the same height from the board is carried out by putting segments of a polyvinyl chloride tube of the same length (12-15mm) on their leads.

In order to silver the copper wire, it must be cleaned to a shine, boiled in a soda solution, then rinsed thoroughly with water and lowered into an old fixer in which a lot of photographic paper or film has been processed. After a while, silver will settle on the wire. Then rinse the wire with water, dry and wipe thoroughly with a cloth. The quality of silver plating and the adhesion strength and adhesion strength of silver to copper depend on the concentration of silver in the fixative solution.

To prepare wood glue, you need two tin cans, one of which must be included in the other. Pieces of dry wood glue are placed in a smaller jar and filled with water. After 8-12 hours, a smaller jar is inserted into a large jar filled with water, and put on a low fire. When the water in a large jar boils, the opened glue will begin to dissolve. Ready glue is similar in density to sour cream. If the glue is very thick, add a little hot water to it and stir.

You can determine the polarity of a DC source using potatoes. To do this, two conductors must be inserted into the cut tuber at a distance of 10-15 mm. From each other and connect a current source to them - greenery will appear around the conductor connected to the positive pole.

Organic glass can be glued with dichloroethane, in which pieces of organic glass are dissolved. The glue should be jelly-like. It is applied to the surfaces to be glued in a thick layer and after 1-2 minutes the surfaces are folded. Excess glue is removed with a rag. Gluing is carried out under a chimney or in a well-ventilated area (on an open window).

Store the glue in a glass container with a ground stopper.

You can make a scale of a receiver or a measuring device using a photo method. To do this, the desired scale is drawn in ink on a piece of paper several times larger than the natural size. Then the scale is photographed in full size (can be reduced). After processing the negative on a black background, all the inscriptions will be white. They can be dyed with aniline dyes in any color. Coloring is done with a soft brush. If the negative is made smaller than necessary, then a positive is printed from the negative onto photographic paper and rolled wet onto glass.

An open block of variable capacitors collects dust, which causes noise and crackles when tuning the receiver, especially when working on short waves. To eliminate these interferences, it is necessary to clean the block from dust with a soft (column) brush, lubricate the rubbing parts with a thin layer of autosol. It is good to make a special cover made of thin plexiglass on the unit to protect it from dust.

To strip a thin winding wire from insulation, it is good to use a fine emery skin. A piece of skin is folded in half with the emery side inward. The stripped end of the wire is lightly clamped and carefully pulled several times between the two surfaces of the skin. After that, the wire deserve.

To clean the end of the litz wire, it must be heated with a match flame and quickly lowered into alcohol. Then the burnt insulation is removed with a clean cloth and the wire is tinned in the usual way. When tinning, care must be taken that the veins of the litz wire do not melt and solder well together.

A capacitor with a capacity of several picofarads can be homemade. One lining of such a capacitor can be a piece of enameled wire with a diameter of 1,0 and a length of 20 mm, the second is a PEV 0,12-0,15 wire wound on it to a turn. With a winding length of 10pf.
If this capacitor is used as a tuning capacitor, the desired capacitance is selected by decreasing or, conversely, increasing the length of the winding of the outer lining.

To fix the ends of the wire of a coil wound on a cylindrical frame, you can use rings 1,5-2 mm wide, cut from a rubber or PVC tube of the appropriate diameter. The rings are put on the frame and the ends of the coil wire are passed under them.

- Organic glass is well polished with a clean and dry cloth with toothpowder. To obtain a mirror surface, polishing mixtures are used.

- When dissolving pieces of polystyrene in benzene, you will get glue for fastening the turns of the coils. The coil lubricated with such glue is dried during the day.

To fix SCR-type cores in coil frames, you can use strips of polyethylene film of suitable thickness. Before the core is screwed in, a strip of polyethylene is lowered into the frame so that its end protrudes 5-7 mm. The width of the strip is selected depending on the size of the gap between the core and the frame.

- The marking of blanks for panels, circuit boards, chassis is carried out using a metal ruler, a square and a sharp scriber. They cut getinax, organic glass and soft metals (for example, aluminum) with a cutter. A sheet of material is placed on a table or board with a smooth, equal surface and a metal ruler is drawn several times with force with the tip of the cutter along the marked cut line. After that, the sheet of material is turned over and shifted so that the cut line runs along the edge of the table or board, and by pressing on the hanging edge, they break. You need to cut a sheet of material to its full length. Breaking out the workpiece from a whole sheet leads to damage to the inner corner, which is usually chipped off.
You need to cut the panel blank, retreating 0,5-1 mm outward from the boundary lines. Then the workpiece is sawn to the desired size with a file. When filing, make sure not to cross the marking lines. The evenness of filing is checked by applying the edge of a metal ruler to the sawn edge of the workpiece, and, looking at the folded edges in the light, determine which places need to be trimmed. The correctness of the angle of the workpiece is checked with a metal square.

The places for drilling holes are marked: on metal - with a core, on getinaks, organic glass and other plastics with a sharp awl. When drilling, make sure that there are no chips on the back of the board around the holes. To do this, a flat board is placed under the board and drilled with a little pressure.

The ferrite rod of the magnetic antenna can be fixed to the circuit board with thick threads. To do this, a piece of rubber tube 7-8 mm long is put on the ends of the rod, and two holes are drilled in the circuit board at the points where the rod is attached. The threads are passed several times into the holes in the board (as if "sewn") and tied in a knot on rubber tubes. The thickness of the walls of the tube should be such that the coils can be moved along the ferrite rod without catching on the board. After tuning and setting the boundaries of the ranges, the coils are fixed on the rod with a few drops of BF-2 glue.

(From the magazines "Radio", "Masterok", "Young Technician", "Model Designer")

Publication: cxem.net

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