I tried to make this homemade VHF receiver in the retro style. Front End from the car radio. KSE marking. Next, the IF block on the KIA 6040, the VLF on the tda2006, the 3GD-40 speaker, in front of which the notch at 4-5 kHz, I don’t know for sure, I picked it up by ear.

Radio receiver circuit

I don’t know how to do digital tuning, so it will be just a variable resistor, for this VHF unit, 4.6 volts is enough to completely cover 87-108 MHz. Initially, I wanted to insert ULF on P213 transistors, since I assembled and rebuilt the "retro", but it turned out to be too bulky, I decided not to show off.

Well network filter installed, of course it won't hurt.

There was no suitable dial indicator, or rather there was, but it was a pity to put - only 2 left, so I decided to redo one of the unnecessary M476 (as in Ocean-209) - straightened the arrow, made a scale.

Backlight - LED Strip Light. Vernier is assembled from parts of various radios, from tube to China. The entire scale with the mechanism is removable, its body is glued from many wooden parts, stiffness is given by the textolite, on which the scale is glued and all this is attracted to the body of the receiver, along the way, additionally pressing the front panels (those with a mesh), which are also removed if desired.

Scale under glass. The tuning knobs are from some junkyard radio, touched up.

In general, a flight of fancy. I have long wanted to try the curvature of my hands by building something similar. And then there was absolutely nothing to do, and the scraps of plywood from the repair remained, and the mesh turned up.

Hello everyone! Here is an article about making an unusual table radio their hands.

It's great when appearance object hides it functionality. In order to use this radio, you have to turn on "Sherlock Holmes" or "Miss Marpool" 🙂 First of all, people around see a simple wooden sculpture, which does not give any hints about what it is and how it can be used. Everything has to be found out experimentally.

For turning on/off, adjusting the range and changing the volume, the radio has two rotating rings lying one above the other. The round base is the speaker that needs to be rotated to turn on homemade.

Due to the spherical shape and weight distribution, craft stably located on the table (the principle of vanka-vstanki). With the exception of electronic parts, the ball radio is made entirely of wood. The body is made up of layers of wood. different breeds(layers have different thicknesses).

Step 1: Construction

After a lot of research, a dozen different sketches and brainstorming, I finally found the "perfect design". Adjustment will be done with the rings, not the wheels of the potentiometers.

Step 2: Wood selection

When making the hull crafts were used different kinds wood. We print out the templates, stick them on the wood and proceed to sawing and cutting out wooden blanks.

Step 3: Assembling the "ball"

Sanding the cut pieces.

Step 4: Turning the body

Set the workpiece to lathe and start sanding. That being said, be very careful. Why? After a second, I was "stunned" by tearing the workpiece into small pieces, but I was lucky and I was able to find every piece in order to glue the case back together. The cause of the gap is an unstabilized workpiece.

Step 5: Adding Electronics

Especially for crafts a simple radio kit was purchased, which included two potentiometers (one for adjusting the volume and on / off the radio, the second for selecting the band).

The interior has mounts for electronics. The shafts of the potentiometers are installed in these mounts. Top for sound, bottom for range change.

When everything is prepared, polished and soldered, you can connect the parts together.

Hull building

For the manufacture of the case, several boards were cut from a sheet of ennobled fiberboard 3 mm thick with the following dimensions:
- front panel measuring 210mm by 160mm;
-two side walls measuring 154mm by 130mm;
- upper and lower wall measuring 210mm by 130mm;

- rear wall measuring 214mm by 154mm;
- plates for mounting the receiver scale measuring 200mm by 150mm and 200mm by 100mm.

With the help of wooden blocks, a box is glued using PVA glue. After the glue has completely dried, the edges and corners of the box are polished to a semicircular state. Irregularities and flaws are putty. The walls of the box are sanded and the edges and corners are re-sanded. If necessary, we putty again and grind the box until we get flat surface. The scale window marked on the front panel is cut out with a finishing saw of a jigsaw. An electric drill drilled holes for the volume control, tuning knob and range switching. We also grind the edges of the resulting hole. We cover the finished box with primer (automobile primer in aerosol packaging) in several layers with complete drying and level the irregularities with emery cloth. We also paint the receiver box with automotive enamel. We cut out the glass of the scale window from thin plexiglass and carefully glue it on the inside of the front panel. At the end, we try on the back wall and install the necessary connectors on it. We attach plastic legs to the bottom with double tape. Operating experience has shown that for reliability, the legs must either be glued tightly or fastened with screws to the bottom.

Holes for handles

Chassis manufacturing

The photographs show the third version of the chassis. The plate for attaching the scale is being finalized for placement in the internal volume of the box. After completion on the board, they are marked and done required holes for governing bodies. The chassis is assembled using four wooden blocks with a section of 25 mm by 10 mm. Bars fasten the back wall of the box and the scale mounting panel. Postal nails and glue are used for fastening. A horizontal chassis panel with pre-made cutouts for placing a variable capacitor, a volume control and holes for installing an output transformer is glued to the lower bars and walls of the chassis.

Electrical circuit of the radio receiver

layout did not work for me. In the process of debugging, I abandoned the reflex scheme. With one HF transistor and the ULF circuit repeated as on the original, the receiver earned 10 km from the transmitting center. Experiments with the power supply of the receiver with reduced voltage, like an earth battery (0.5 Volts), showed insufficient power of the amplifiers for loud-speaking reception. It was decided to raise the voltage to 0.8-2.0 volts. The result was positive. Such a receiver circuit was soldered and installed in a two-band version in a country house 150 km from the transmitting center. With a connected external fixed antenna 12 meters long, the receiver installed on the veranda completely sounded the room. But when the air temperature dropped with the onset of autumn and frost, the receiver switched to self-excitation mode, which forced the device to adjust depending on the air temperature in the room. I had to study the theory and make changes to the scheme. Now the receiver worked steadily down to -15C. The fee for the stability of work is a decrease in efficiency by almost half, due to an increase in the quiescent currents of transistors. In view of the lack of constant broadcasting, he refused the DV range. This single-band version of the circuit is shown in the photograph.

Mounting the radio

Homemade printed circuit board receiver is made under the scheme of the original and has already been finalized in field conditions to prevent self-excitation. The board is installed on the chassis with hot glue. To shield the inductor L3, an aluminum shield connected to a common wire is used. The magnetic antenna in the first versions of the chassis was installed at the top of the receiver. But periodically they put on the receiver metal objects and cell phones that interfered with the operation of the device, so I placed the magnetic antenna in the basement of the chassis, simply gluing it to the panel. KPI with an air dielectric is installed with screws on the scale panel, the volume control is also fixed there. The output transformer is used ready-made from a tube tape recorder, I admit that any transformer from a Chinese power supply is suitable for replacement. The receiver does not have a power switch. Volume control is required. At night and on “fresh batteries”, the receiver starts to sound loud, but due to primitive design ULF during playback, distortion begins, which is eliminated by lowering the volume. The scale of the receiver was made spontaneously. The appearance of the scale was compiled using the VISIO program, with the subsequent transfer of the image to a negative view. The finished scale was printed on thick paper laser printer. The scale must be printed on thick paper; with temperature and humidity changes, office paper will go in waves and will not restore its previous appearance. The scale is completely glued to the panel. Copper winding wire is used as an arrow. In my version, this is a beautiful winding wire from a burned-out Chinese transformer. The arrow is fixed on the axis with glue. The tuning knobs are made from carbonated drink caps. The handle of the desired diameter is simply glued into the lid with hot glue.

Board with elements

Receiver assembly

Radio Power

As mentioned above, the "earth" power option did not go. As alternative sources it was decided to use dead batteries of the "A" and "AA" format. The farm constantly accumulates dead batteries from flashlights and various gadgets. Dead batteries with a voltage below one volt became power sources. The first version of the receiver worked for 8 months on one "A" battery from September to May. A container is glued on the rear wall especially for power supply from AA batteries. Low current consumption assumes that the receiver is powered by solar panels garden lights, but so far this issue is irrelevant due to the abundance of AA format power supplies. The organization of power supply with waste batteries served as the assignment of the name "Recycler-1".

Homemade radio loudspeaker

I do not urge you to use the loudspeaker shown in the photo. But it is this box from the distant 70s that gives the maximum volume from weak signals. Of course, other columns are also suitable, but the rule works here - the more the better.

Outcome

I would like to say that the assembled receiver, having a low sensitivity, is not affected by radio interference from TVs and switching power supplies, and the quality of sound reproduction from industrial AM receivers is different purity and saturation. During any power failures, the receiver remains the only source of listening to programs. Of course, the receiver circuit is primitive, there are circuits of better devices with economical power supply, but this do-it-yourself receiver works and copes with its “duties”. Spent batteries are regularly burned out. The scale of the receiver is made with humor and jokes - no one notices this for some reason!

Final video

Finally, the long-awaited moment comes when the created apparatus begins to “breathe”, and the question arises: how to close its “insides” and give the design completeness in order to use it with convenience. This question should be concretized and decided what the case is intended for.

If it is enough that the device has a beautiful appearance and "fits" into the interior, you can make a case from fiberboard sheets, plywood, plastics, fiberglass. The body parts are connected with screws or glue (using additional "fittings", i.e. rails, corners, scarves, etc.). To give a "presentation" the case can be painted or pasted over with a self-adhesive film.

simple and convenient way manufacturing small cases at home - from sheets of foil fiberglass. First, “the laying of all nodes and boards inside the volume is carried out and the dimensions of the case are pretended. Sketches of walls, partitions, board fastening details, etc. are drawn. According to the finished sketches, the dimensions are transferred to foil fiberglass, and blanks are cut out. You can pre-make all the holes for the controls and indicators, since the plates are much more convenient to work with than with the finished box.
The cut parts are adjusted, then, having fixed the workpieces at right angles to each other, the joints on the inside are soldered with ordinary solder with a sufficiently powerful soldering iron. There are only two “subtleties” in this process: do not forget to give allowances for the thickness of the material on the right sides of the workpieces and take into account that the solder shrinks in volume during solidification, and the soldered plates must be firmly fixed for the time the solder cools so that they are not “led”.
When the device needs protection from electric fields, the case is made of conductive materials (aluminum and its alloys, copper, brass, etc.). It is advisable to use steel when shielding is required and from magnetic field, and the mass of the device does not have of great importance. A case made of steel sufficient to provide mechanical strength of thickness (usually 0.3 ... 1.0 mm, depending on the size of the device), is especially preferable for transceiver equipment, as it shields the created device from electromagnetic radiation, interference, interference, etc. .
Thin sheet steel has sufficient mechanical strength, lends itself to bending, stamping, quite cheap. True, ordinary steel also has a negative property: susceptibility to corrosion (rust). Used to prevent corrosion various coatings: oxidation, zinc plating, nickel plating, primer (before painting). In order not to impair the shielding properties of the housing, its priming and painting should be carried out after complete assembly (or leave the oxidized strips of panels in contact with each other unpainted (with a split housing). To combat this, spring "combs" (springing strips of oxidized hard steel welded or riveted to the panels) are used, which, during assembly, ensure reliable contact between the panels.

A metal case made of two U-shaped parts enjoys well-deserved popularity.(Fig. 1), bent from plastic sheet metal or alloy.

The dimensions of the parts are chosen so that when they are installed one into the other, a closed case without gaps is obtained. To connect the halves with each other, screws are used, screwed into the threaded holes in the shelves of the base 1 and the corners 2 riveted to it (Fig. 2).

With a small thickness of the material (less than half the thread diameter), it is recommended to first drill the threaded hole with a drill, the diameter of which is equal to half the thread diameter. Then, by hammer blows on a round awl, the hole is given a funnel shape, after which a thread is cut in it.

If the material is plastic enough, you can do without corners 2, replacing them with bent "legs" on the very base (Fig. 3).

An even more "advanced" version of the rack, shown in Fig. 4.
Such a stand 3 not only fastens the top panel 1 with the bottom 5, but also fixes it in the chassis 6, on which the elements of the manufactured device are placed. Therefore, no additional fasteners are needed, and the panels do not “decorate” numerous screws. The bottom panel is attached to the stand with screw 2 through leg 4.
Thickness required material depends on the size of the case. For a small body (with a volume of up to about 5 cubic dm), a sheet with a thickness of 1.5 ... 2 mm is used. A larger body requires, accordingly, a thicker sheet - up to 3 ... 4 mm. This primarily applies to the base (bottom panel), since it bears the main power load.

Manufacturing begins with the calculation of the dimensions of the blanks (Fig. 5).

The length of the workpiece is calculated by the formula:

Having determined the length of the first workpiece, it is cut out of the sheet and bent (for steel and brass, the bending radius R is equal to the thickness of the sheet, for aluminum alloys it is 2 times greater). After that, the resulting dimensions a and c are measured. Given the existing size c, the width of the second workpiece (C-2S) is determined and its length is calculated using the same formula, substituting:
- instead of a - (a-S);
- instead of R1 - R2;
- instead of S - t.

This technology guarantees precise connection of parts.
After the manufacture of both halves of the body, they are adjusted, marked and drilled for mounting holes. V necessary places holes and windows are cut for control knobs, connectors, indicators and other elements. Check assembly in progress and final fit corps.

Sometimes it is difficult to place the entire "stuffing" of the device in the U-shaped half. For example, on the front panel you want to install a large number of indication and control organs. It is inconvenient to cut windows for them in a bent part. Help out here combined option. The body half with the front panel is made from separate sheet blanks. For their fastening, you can use special corners shown in Fig.6.

Such a detail conveniently fastens three walls at once in the corner of the case. The dimensions of the corners depend on the dimensions of the fastened structural elements.

To make a corner, a strip of mild steel is taken, and fold lines are marked on it. The central part of the workpiece is clamped in a vise. With light hammer blows, the strip is bent, then turned over so that the bent part lies on side surface vise, and the middle part was slightly clamped. In this position, the bend is corrected and the deformation of the strip is eliminated. Now the second side of the part is bent, and, after editing, a ready-made fastener is obtained. It remains to mark in place and drill holes in which to cut the thread.

Equipment, especially lamp equipment, requires ventilation of the case. It is not at all necessary to drill holes throughout the body, it is enough to drill them in places where there are powerful lamps (in the top cover of the case), on the back wall above the chassis, several rows of holes in the central part of the bottom cover of the case and two or three rows of holes on the side walls (at the top). There should also be holes around each lamp in the chassis. Over powerful lamps with forced ventilation windows are usually cut out in which a metal mesh is fixed.

V Lately, as a result of rapid moral aging, cases from computer system blocks appeared in landfills. These cases can be used to create various amateur radio equipment, especially since the case takes up very little space in width. But such a vertical layout is not always suitable. Then you can take the casing from the system unit, cut it to the required dimensions and “join” it with the “cut” from the second same casing (or separate panels - Fig. 7, 8).

With careful manufacture, the case turns out to be quite good and already painted.

Radio receiver housing, decorative and protective elements

The acoustic characteristics of the radio receiver are determined not only by the frequency characteristics of the low-frequency path and loudspeaker, but to a large extent depend on the volume and shape of the case itself. The body of the radio receiver is one of the links in the acoustic path. No matter how good the electro-acoustic parameters of the low-frequency amplifier and loudspeaker are, all their advantages will be reduced if the radio receiver case is poorly designed. It should be borne in mind that the body of the broadcast receiver is at the same time decorative element designs. For this purpose, the front part of the case is closed with radio tissue or decorative grille. Finally, to protect the listener from accidental damage when touching conductive parts, the chassis of the radio receiver in the housing is protected back wall, on which the blocking of the power circuit is installed. Therefore, decorative and protective elements structures that are elements of the acoustic path, as well as methods of their mechanical fastening, can have a significant impact on the quality of reproduction of sound programs. Therefore, we will consider each structural element of the broadcasting receiver housing separately.

radio housing must meet the following basic requirements: its design must not limit the frequency range regulated by GOST 5651-64; manufacturing process and assembly must comply with the requirements of mechanized production; manufacturing cost should be low; external design is highly artistic.

To meet the first requirement, the housing must provide good reproduction of the low and high frequencies of the radio's audio range. For this purpose, it is necessary to make preliminary calculations of the shape of the hull. The final determination of its dimensions and volume is verified by the results of tests in an acoustic chamber.

In acoustic calculations, the loudspeaker cone is considered as a piston oscillating in the air, which creates areas of high and low atmospheric pressure during forward and reverse motion. Therefore, it is far from indifferent in which case the loudspeaker is located: with an open or closed rear wall. In a case with an open rear wall of condensation and rarefaction, arising from the movement of the rear and front surfaces of the diffuser, bending around the walls of the housing, are superimposed on each other. In the case when the phase difference of these oscillations is equal to n, the sound pressure in the plane of the diffuser decreases to zero.

An increase in the depth of the hull according to the design requirements is quite acceptable. The dimensions of radio receivers with several loudspeakers cannot be calculated using the above formulas. In practice, the dimensions of enclosures with multiple loudspeakers are determined experimentally from the results of acoustic tests.

The design of cases of broadcasting receivers in the desktop version with a closed back wall is usually not used. This is explained by the fact that it is very difficult and impractical to design radio receiver cases with a closed volume, since the heat exchange mode of radio components worsens. On the other hand, tight-backed cabinets cause the loudspeaker to resonate higher and have a flatter frequency response for more than high frequencies. To reduce uneven frequency response at high frequencies inner side The body is upholstered with sound-absorbing material. Naturally, such a complication of the design can only be allowed in radio receivers of the highest classes, in furniture design with remote acoustic systems.

To fulfill the second requirement for cases, it is necessary to be guided by the following considerations: when choosing a material for a case, it is desirable to take into account the standards recommended by GOST 5651-64 for amplification paths in terms of sound pressure, given in Table. 3.

Table 3

As can be seen from Table. 3, depending on the class of the radio receiver, the norms of the frequency range of the entire amplification path in terms of sound pressure also change. Therefore, it is not always advisable for all classes of radio receivers to choose high-quality materials with good acoustic properties. In some cases, this does not lead to an improvement in the acoustic characteristics of the receivers, but increases their cost, since the loudspeaker is selected in accordance with GOST standards, which determines the range of reproducible frequencies. For these reasons, there is no need to improve the acoustic characteristics of the cabinet, when the sound source itself does not provide the possibility of their implementation. On the other hand, a low-frequency path having a narrower frequency range makes it possible to reduce the cost of the low-frequency amplifier design.

According to statistics, the cost of a wooden case is from 30-50% of the total cost of the main components of the receiver. The relatively high cost of the hull requires the designer to be careful in choosing its design. What is acceptable when designing radios upper class, is completely inapplicable for class IV receivers designed for a wide range of consumers. For example, in radio receivers of the highest and first classes, in some cases, the walls of the case are made from separate pine boards laid between two thin sheets of plywood to improve sound reproduction. Front sides the hulls are glued with fine wood veneer, varnished and polished. At the same time for hull manufacturing class III and IV radios use cheap plywood, non-deficient wood veneer, textured paper or plastics. Metal cases are not currently used due to non-

satisfactory acoustic qualities and the appearance of overtones that are unpleasant to the ear.

To analyze the design, it is advisable to use the so-called unit cost, i.e., the cost per unit volume or weight of the material. In each case, knowing the cost of the hull and the amount of material used, it is possible to determine the unit cost. Regardless of the volume of material spent on the manufacture of the case for a certain technological process, its exterior finish, the unit cost has a constant specific value. For example, in the manufacture of receiver cases at a specialized enterprise or in workshops, the unit cost is 0.11 kopecks. This value of the unit cost also takes into account overhead costs: the cost of the material, its processing, finishing, wages. It should be borne in mind that the value of the unit cost of the hull corresponds to well-defined materials and technological processes. The value is 0.11 kop. refers to cases made of plywood, pasted over with cheap veneer (oak, beech, etc.) and varnished without subsequent polishing. For cases carefully polished and pasted over with more valuable wood species, the unit cost increases by approximately 60% - Thus, to determine the cost of a wooden radio case, it is necessary to multiply the unit cost by the amount of material (plywood) used.

The process of pasting the body of the radio receiver with precious woods and subsequent polishing is quite laborious, as it involves many manual operations, requires large areas for its processing and tunnel kilns for drying treated surfaces. In order to save veneer, which is in short supply for a number of enterprises, it is replaced with texturized paper, on which a pattern of fibers is applied. tree species. However, pasting radio receivers with texturized paper does not improve the situation, since to create a good presentation, multiple varnishing (5-6 times) is required, followed by drying.
in tunnel ovens. In addition, an additional operation is introduced - painting the corners of the body, where sheets of texturized paper are joined. The cost of buildings finished in this way does not decrease due to the high labor intensity of the work.

The choice of material thickness for the walls of the housing should be made taking into account technical requirements presented to the acoustic system of the radio receiver. Unfortunately, the technical literature lacks detailed information about the choice of material grade and its effect on the acoustic parameters of receivers. Therefore, when designing hulls, one can only be guided by summary presented in the work. For example, in high-end radio receivers for reproducing low frequencies of 40-50 Hz with a sound pressure of 2.0-2.5 N!m2, the thickness of the walls made of plywood or joinery boards must be at least 10-20 mm. For radio receivers of classes I and II, when reproducing low frequencies of 80-100 Hz and sound pressure of the order of 0.8-1.5 n / m2, a plywood thickness of 8-10 mm is allowed. Cases for acoustic systems of radio receivers of III and IV classes, having a cutoff frequency of 150-200 Hz and sound pressure up to 0.6 n / m2, can have a wall thickness of 5-6 mm. Naturally, it is very difficult to make wooden cases with a wall thickness of 5-6 mm, since it is impossible to ensure sufficient structural strength. Housings with small wall thicknesses are usually made of plastic, however, even in this case stiffening ribs must be provided to eliminate vibrations of the housing walls.

For economic reasons, the manufacture of plastic cases for radio receivers is more profitable than wooden ones. Despite the technological and economic advantages of plastics for the manufacture of housings, their use is limited to broadcasting receivers with large dimensions and high acoustic characteristics.

It is well known that wood has good acoustic properties, so radios

the upper classes tend to have wooden hulls. For these reasons, cases made of plastics are made only for class IV radios and very rarely for class III radios.

The body of the radio receiver must have sufficient structural strength, withstand mechanical tests for impact strength, vibration resistance and strength during transportation. Application methods, adopted in the furniture industry, i.e., the implementation of butt connections using spiked joints, is not justified by economic considerations, since the manufacturing process becomes more complicated, and, consequently, the standard time for processing and assembly operations increases. Usually, the angular interfaces of the walls of the housings of broadcasting receivers are performed more simple methods, which do not cause technological production difficulties. For example, the walls of the case are connected with bars or squares glued into the corner joints, or with the help of wooden planks inserted with glue into the slots of the parts to be joined. wooden walls can be connected with metal squares, brackets, strips, etc. And yet, despite the measures taken to simplify the manufacturing processes wooden cases, their cost remains relatively high.

The most labor intensive technological processes are pasting wood veneer, varnishing and polishing of body surfaces. polishing process assembled body especially difficult in corner joints, since in these cases it is impossible to avoid manual operations. It is natural, therefore, that the efforts of designers and technologists should be aimed at creating such a hull design, the manufacture of parts of which and assembly processes could be mechanized as much as possible. The most rational in this regard is the prefabricated hull design, when individual parts of a simple shape pass final processing and finishing, and then

mechanically combined into a common structure.

Rice. 37. The design of the prefabricated body.

There are other designs of collapsible buildings. One of the domestic radio factories has developed a design in which the side walls are connected by metal panels using bolted connections. In this case, the radio receiver chassis is an independent unit, independent of the housing design.

Naturally, the above examples do not exhaust all the possibilities for developing design designs for detachable housings. One thing is obvious - such designs are the simplest and cheapest.