Receiver in retro style with hands. DIY steampunk radio. Electrical circuit of the radio receiver

IN Lately There is a great interest in antique and retro radio equipment. The collections include both retro radio equipment from the 40-60s and real antique radio equipment from the 10-30s. In addition to collecting original products, there is a growing interest in collecting and making so-called replicas. This is very interesting direction amateur radio creativity, but first let’s explain the meaning of this term.

There are three concepts: original, copy and replica of an antique product. The term "original" does not need any description. A copy is a modern repetition of an antique product, up to the smallest details, materials used, design solutions, etc. A replica is a modern product, made in the style of products of those years and, if possible, with approximate constructive solutions. Accordingly, the closer the replica is to original products in terms of style and detail, the more valuable it is.

Nowadays, many so-called radio souvenirs have appeared on sale, mainly made in China, designed in the form of retro and even antique radio equipment. Unfortunately, upon closer examination it is clear that its value is low. Plastic handles, painted plastic, the body material is covered with MDF film. All this speaks of a very low-quality product. As for their “filling,” it is, as a rule, a printed circuit board with modern integrated elements. In terms of quality, the internal installation of such products also leaves much to be desired. The only “advantage” of these products is their low price. Therefore, they may be of interest only to those who, without going into technical details or simply not understanding them, he wants to have an inexpensive “cool thing” on his desk in his office.

As an alternative, I would like to present a receiver design that fully meets the requirements of an interesting and high-quality replica. This is a super regenerative tube VHF FM receiver(Fig. 1), operating in the frequency range 87...108 MHz. It is assembled using octal series radio tubes, since the use of tubes with pin base, older and more suitable in style, is not possible due to the high operating frequency of the receiver.

Rice. 1. Super regenerative tube VHF FM receiver

Bronze terminals, control knobs and brass nameplates are an exact copy of those used in products of the 20s of the last century. Some elements of fittings and design are original. All radio tubes of the receiver are open, except for the screens. All inscriptions are made on German. The receiver body is made of solid beech. The installation, with the exception of some high-frequency components, is also made in a style as close as possible to the original of those years.
The front panel of the receiver contains a power switch (ein/aus), a frequency setting knob (Freq. Einst.), and a frequency scale with a tuning pointer. The top panel has a volume control (Lautst.) on the right and a sensitivity control (Empf.) on the left. Also on top panel There is a dial voltmeter, the illumination of the scale of which indicates that the receiver's power is turned on. On the left side of the housing there are terminals for connecting an antenna (Antenne), and on the right there are terminals for connecting an external classical or horn loudspeaker (Lautsprecher).

I would like to note right away that the further description of the receiver device, despite the presence of drawings of all the parts, is for informational purposes only, since the repetition of such a design is accessible to experienced radio amateurs, and also presupposes the presence of certain wood and metalworking equipment. In addition, not all elements are standard and purchased. As a result, some installation dimensions may differ from those shown in the drawings, since they depend on those elements that are available. Those who want to repeat this receiver “one-to-one” and who need more detailed information about the design of certain parts, assembly and installation are offered drawings, as well as the opportunity to ask a question directly to the author.

The receiver circuit is shown in Fig. 2. The antenna input is designed to connect a symmetrical reduction cable to a VHF antenna. The output is designed to connect a loudspeaker with a resistance of 4-8 Ohms. The receiver is assembled according to the 1-V-2 circuit and contains a UHF on the VL1 pentode, a super-regenerative detector and a preliminary ultrasonic on the VL3 double triode, a final ultrasonic on the VL6 pentode and a power supply on the T1 transformer with a rectifier on the VL2 kenotron. The receiver is powered from a 230 V network.

Rice. 2. Receiver circuit

UHF is a range amplifier with spaced circuit tuning. Its tasks are to amplify high-frequency oscillations coming from the antenna and to prevent the penetration of the super-regenerative detector’s own high-frequency oscillations into it and radiation into the air. The UHF is assembled on a high-frequency pentode 6AC7 (analogue - 6Zh4). The antenna is connected to the input circuit L2C1 using the L1 coupling coil. The input impedance of the cascade is 300 Ohms. The input circuit in the grid circuit of the VL1 lamp is set to a frequency of 90 MHz. The setting is carried out by selecting capacitor C1. Circuit L3C4 in the anode circuit of lamp VL1 is tuned to a frequency of 105 MHz. The setting is carried out by selecting capacitor C4. With this configuration of the circuits, the maximum UHF gain is about 15 dB, and the unevenness of the frequency response in the frequency range 87...108 MHz is about 6 dB. Communication with the subsequent cascade (super-regenerative detector) is carried out using coupling coil L4. Using variable resistor R3, you can change the voltage on the screen grid of the VL1 lamp from 150 to 20 V and thereby change the UHF transmission coefficient from 15 to -20 dB. Resistor R1 serves to automatically generate a bias voltage (2 V). Capacitor C2, shunting resistor R1, eliminates AC feedback. Capacitors C3, C5 and C6 are blocking. The voltages at the terminals of the lamp VL1 are indicated for the upper position of the resistor R3 engine in the diagram.

Super regenerative detector assembled on the left half of a double triode VL3 6SN7 (analogue - 6N8S). The superregenerator circuit is formed by inductor L7 and capacitors C10 and C11. Variable capacitor C10 is used to adjust the circuit in the range of 87...108 MHz, and capacitor C11 is used to “set” the boundaries of this range. The grid circuit of the super-regenerative detector triode includes a so-called “gridlick” formed by capacitor C12 and resistor R6. By selecting capacitor C12, the damping frequency is set to about 40 kHz. The super-regenerator circuit is connected to the UHF using communication coil L5. The supply voltage of the anode circuit of the superregenerator is supplied to the outlet of the loop coil L7. Choke L8 is the load of the superregenerator at high frequency, choke L6 is at low frequency. Resistor R7 together with capacitors C7 and C13 form a filter in the power circuit, capacitors C8, C14, C15 are blocking ones. The AF signal through capacitor C17 and low-pass filter R11C20 with a cutoff frequency of 10 kHz is supplied to the input of the preliminary ultrasonic filter.

Preliminary ultrasound assembled on the right (according to the diagram) half of the triode VL3. The cathode circuit includes resistor R9 for automatically generating a bias voltage (2.2 V) on the grid and inductor L10, which reduces the gain at frequencies above 10 kHz and serves to prevent the penetration of superregenerator damping pulses into the final ultrasonic frequency. From the anode of the right triode VL3, through the isolation capacitor C16, the AF signal is supplied to the variable resistor R13, which serves as a volume control.

The power supply provides power to all components of the receiver: alternating voltage 6.3 V - to power the filament lamps, constant unstabilized voltage 250 V - to power the anode circuits of the UHF and the final ultrasonic frequency. The rectifier is assembled using a full-wave circuit on a VL2 5V4G kenotron (analogue - 5Ts4S). Rectified voltage ripples are smoothed out by the C9L9C18 filter. The supply voltage of the super-regenerator and preliminary ultrasonic amplifier is stabilized by a parametric stabilizer based on resistor R14 and gas-discharge zener diodes VL4 and VL5 VR105 (analogue - SG-3S). The R12C19 RC filter additionally suppresses voltage ripple and zener diode noise.

Design and installation. The UHF elements are mounted on the main receiver chassis around the lamp panel. To prevent self-excitation of the cascade, the grid and anode circuits are separated by a brass screen. The communication coils and loop coils are frameless and mounted on textolite mounting racks (Fig. 3 and Fig. 4). Coils L1 and L4 are wound with silver-plated wire with a diameter of 2 mm on a mandrel with a diameter of 12 mm with a pitch of 3 mm.

Rice. 3. Communication coils and loop coils are frameless, mounted on textolite mounting racks

Rice. 4. Communication coils and loop coils are frameless, mounted on textolite mounting racks

L1 contains 6 turns with a tap in the middle, and L4 contains 3 turns. Contour coils L2 (6 turns) and L3 (7 turns) are wound with silver-plated wire with a diameter of 1.2 mm on a mandrel with a diameter of 5.5 mm, the winding pitch is 1.5 mm. The loop coils are located inside the communication coils.

The screen grid voltage of the VL1 lamp is controlled by a dial voltmeter located on the top panel of the receiver. The voltmeter is implemented on a milliammeter with a total deviation current of 2.5 mA and an additional resistor R5. Subminiature scale backlight lamps EL1 and EL2 (СМН6.3-20-2) are located inside the milliammeter housing.

Rice. 5. Elements of a super-regenerative detector and preliminary ultrasonic sounder, mounted in a separate shielded block

The elements of the super-regenerative detector and preliminary ultrasonic sounder are mounted in a separate shielded block (Fig. 5) using standard mounting racks (SM-10-3). Variable capacitor C10 (1KPVM-2) is fixed to the block wall using glue and a textolite sleeve. Capacitors C7, C8, C14 and C15 are through series KTP. Inductor L6 is connected through capacitors C7 and C8. The supply voltage to the shielded unit is supplied through capacitor C15, and the filament voltage is supplied through capacitor C14. Oxide capacitor C19 - K50-7, choke L8 - DPM2.4. The L6 choke is homemade, it is wound in two sections on a magnetic circuit Ш14х20 and contains 2х8000 turns of PETV-2 0.06 wire. Since the choke is sensitive to electromagnetic interference (in particular, from power supply elements), it is mounted on a steel plate above the UHF (Fig. 6) and covered with a steel screen. It is connected with shielded wires. The braid is connected to the body of the super-regenerator unit. To manufacture the L10 inductor, an SB-12a armored magnetic circuit with a permeability of 1000 was used; a winding of 180 turns of PELSHO 0.06 wire was wound on its frame. Coils L5 and L7 are wound with silver-plated wire with a diameter of 0.5 mm in increments of 1.5 mm, on a ribbed ceramic frame with a diameter of 10 mm, which is glued using a textolite sleeve into the hole of the lamp panel. Inductor L7 contains 6 turns with a tap of 3.5 turns, counting from the top one in the output diagram, communication coil L5 - 1.5 turns.

Rice. 6. Choke mounted on steel plate above UHF

The shielded unit is secured to the main receiver chassis using a threaded flange. The connection between capacitor C16 and resistor R13 is made with a shielded wire with the shielding braid grounded near resistor R13. The rotation of the rotor of the C10 capacitor is carried out using a textolite axis. To ensure the necessary strength and wear resistance of the splined connection of the axle and the C10 capacitor, a cut was made in the axle into which a fiberglass laminate plate was glued. One end of the plate is sharpened so that it fits tightly into the slot of the C10 capacitor. The axle is fixed and pressed against the capacitor slot using a spring washer placed between the bracket bushing and the driven pulley fixed to the axle (Fig. 7).

Rice. 7. Shielded block

The vernier is assembled on two brackets fixed to the front wall of the shielded superregenerator block (Fig. 8). The brackets can either be made independently, according to the attached drawings, or you can use a standard aluminum profile with minor modifications. To transmit rotation, a nylon thread with a diameter of 1.5 mm is used. You can use a “severe” shoe thread of the same diameter. One end of the thread is attached directly to one of the pins of the driven pulley, and the other to the other pin through a tension spring. Three turns of thread are made in the groove of the vernier's driving axis. The driven pulley is fixed on the axis so that in the middle position of the variable capacitor C10 the end hole for the thread is located diametrically opposite to the driving axis of the vernier. Both axles are fitted with extension attachments secured to them with locking screws. A frequency adjustment knob is installed on the drive axis attachment, and a scale dial indicator is installed on the driven axis attachment.

Rice. 8. Vernier

Most elements of the final ultrasonic amplifier are mounted on the terminals of the lamp panel and mounting racks. The output transformer T2 (TVZ-19) is installed on an additional chassis and oriented at an angle of 90° relative to the magnetic circuit of the inductor L9 of the power supply. The connection between the control grid of the VL6 lamp and the motor of resistor R13 is made with a shielded wire with grounding of the shielding braid near this resistor. Oxide capacitor C21 - K50-7.

The power supply (except for elements L9, R12 and R14, which are mounted on an additional chassis) is mounted on the main chassis of the receiver. Unified choke L9 - D31-5-0.14, capacitor C9 - MBGO-2 with flanges for mounting, oxide capacitors C18, C19 - K50-7. For the manufacture of transformer T1 with an overall power of 60 VA, a magnetic circuit Ш20х40 was used. The transformer is equipped with stamped metal covers. On top cover a VL2 kenotron panel was installed along with a brass decorative nozzle (Fig. 9). A mounting block is installed on the bottom cover, where the necessary terminals of the transformer windings and the terminal of the kenotron cathode are brought out. Attached power transformer to the main chassis with studs tightening its magnetic circuit. The stud nuts are four threaded posts on which the additional chassis is attached (Fig. 10).

Rice. 9. VL2 kenotron panel together with a brass decorative nozzle

Rice. 10. Additional chassis

The entire installation of the receiver (Fig. 11) is carried out with a single-core copper wire with a diameter of 1.5 mm, placed in a varnished fabric tube of various colors. Its ends are fixed using nylon thread or pieces heat shrink tube. The assembly wires assembled into bundles are connected to each other with copper clamps.

Rice. 11. Mounted receiver

Before installation, transformer T1 and capacitors C13, C18, C19 and C21 are painted with a spray gun with “Hammerite hammer black” paint. The power transformer is painted in a tightened state. When painting capacitors, it is necessary to protect bottom part their metal case, which is adjacent to the chassis. To do this, before painting, the capacitors can, for example, be mounted on a thin sheet of plywood, cardboard or other suitable material. Before painting the power transformer, it is necessary to remove the decorative brass attachment and protect the kenotron panel from paint with masking tape.

The receiver body is wooden and made of solid beech. The side walls are connected using a tenon joint with a pitch of 5 mm. The front part of the body is lowered to accommodate front panel. Rectangular holes are made in the side and rear walls of the case. The outer edges of the holes are machined with an edge radius cutter. On the inner edges of the holes there are undercuts for fastening the panels. In the side openings of the case there are panels with contact input and output terminals, and in the rear there is a decorative grille. The upper and lower parts of the body are also made of solid beech and finished with edge cutters. All wooden parts are tinted with mocha stain, primed and varnished with professional paints and varnishes from Votteler with intermediate sanding and polishing according to the instructions supplied with these paintwork materials.

The front panel is painted with “Hammerite black smooth” paint using a technology that produces a large, clearly defined shagreen (large-droplet spraying onto a heated surface). The front panel is secured to the receiver body with brass self-tapping screws of appropriate sizes with semicircular head and a straight slot. Similar brass fasteners are available in some hardware stores. All nameplates are custom-made and made on a CNC machine with laser engraving on brass plates 0.5 mm thick. They are attached to the front panel using M2 screws, and to the wooden panel using brass self-tapping screws.

After assembling the receiver and checking the installation for possible errors, you can begin adjustments. To do this, you will need a high-frequency oscilloscope with an upper limit frequency of at least 100 MHz, a capacitor capacitance meter (from 1 pF) and, ideally, a spectrum analyzer with a maximum frequency of at least 110 MHz and a sweep frequency generator (SWG) output. If the analyzer has an output spectrum of the MFC, it is possible to observe the frequency response of the objects under study. A similar device is, for example, the SK4-59 analyzer. If this is not available, you will need an RF generator with the appropriate frequency range.

A correctly assembled receiver begins to work immediately, but requires adjustment. First check the power supply. To do this, remove lamps VL1, VL3 and VL6 from the panels. Then a load resistor with a resistance of 6.8 kOhm and a power of at least 10 W is connected in parallel with capacitor C18. After turning on the power supply and warming up the kenotron VL2, the gas-discharge zener diodes VL4 and VL5 should light up. Next, measure the voltage on capacitor C18. With an unloaded filament winding, it should be slightly higher than indicated in the diagram - about 260 V. At the anode of the VL4 zener diode, the voltage should be about 210 V. AC voltage the filament of radio tubes VL1, VL3 and VL6 (if they are absent) is about 7 V. If all the above voltage values ​​are normal, the test of the power supply can be considered complete.

Unsolder the load resistor and install lamps VL1, VL3 and VL6 in their places. The sensitivity control slider (resistor R3 is set to the top position according to the diagram, and the volume control (resistor R13) is set to the minimum volume position. Connect to the output (terminals XT3, XT4) dynamic head resistance 4...8 Ohm. After turning on the receiver and warming up all the radio tubes, check the voltages on their electrodes in accordance with those indicated in the diagram. When increasing the volume by turning resistor R13, the characteristic high-frequency noise of the super-regenerator should be heard in the loudspeaker. Touching the antenna terminals should be accompanied by increased noise, which indicates proper operation of all stages of the receiver.

The setup begins with a super-regenerative detector. To do this, remove the screen from the VL3 lamp and wind a communication coil around its cylinder - two turns of a thin insulated mounting wire. Then install the screen back by releasing the ends of the wire through the top hole of the screen and connecting the oscilloscope probe to them. At proper operation superregenerator, characteristic flashes of high-frequency oscillations will be visible on the oscilloscope screen (Fig. 12). By selecting capacitor C12 it is necessary to achieve a flash repetition rate of about 40 kHz. When adjusting the receiver over the entire range, the flash repetition rate should not change noticeably. Then they check the tuning range of the super-regenerator, which determines the tuning range of the receiver, and correct it if necessary. To do this, instead of an oscilloscope, a spectrum analyzer is connected to the ends of the communication winding. The selection of capacitor C11 sets the boundaries of the range - 87 and 108 MHz. If they differ greatly from those indicated above, it is necessary to slightly change the inductance of coil L7. At this point, setting up the super regenerator can be considered complete.

Rice. 12. Oscilloscope readings

After adjusting the super-regenerator, remove the communication coil from the VL3 lamp cylinder and proceed to establishing the UHF. To do this, you need to unsolder the wires going to the inductor L6, remove the inductor itself and the plate on which it is attached (see Fig. 6) from the chassis. This will open access to the UHF installation and turn off the super-regenerator cascade. Disabling the super-regenerator is necessary so that its own oscillations do not interfere with the UHF tuning. The output of the spectrum analyzer (or the output of the RF generator) is connected to one of the extreme and middle terminals of the inductor L1. The input of a spectrum analyzer or an oscilloscope is connected to the L4 coupling coil. It should be recalled that connecting devices to the receiver elements must be done with coaxial cables of minimum length, cut on one side for soldering. The termination ends of these cables should be as short as possible and soldered directly to the terminals of the corresponding elements. It is strictly not recommended to use oscilloscope probes to connect devices, as is often done.

By selecting capacitor C1, tune the UHF input circuit to a frequency of 90 MHz, and the output circuit by selecting capacitor C4 to a frequency of 105 MHz. It is convenient to do this by temporarily replacing the corresponding capacitors with small-sized trimmers. If a spectrum analyzer is used, the adjustment is performed by observing the real frequency response on the analyzer screen (Fig. 13). If an RF generator and an oscilloscope are used, first adjust the input circuit, and then the output circuit according to the maximum signal amplitude on the oscilloscope screen. After completing the setup, you must carefully unsolder trimmer capacitors, measure their capacity and select permanent capacitors with the same capacity. Then you need to recheck the frequency response of the UHF cascade. At this point, setting up the receiver can be considered complete. It is necessary to return the inductor L6 to its place and connect it, check the operation of the receiver over the entire frequency range.

Rice. 13. Analyzer readings

The operation of the receiver is checked by connecting an antenna to the input (terminals XT1, XT2), and a loudspeaker to the output. Keep in mind that a super regenerative detector can only receive FM signals on the slopes of its circuit's resonance curve, so there will be two settings for each station.

If an authentic horn manufactured in the 20s of the last century is intended to be used as a loudspeaker, it is connected to the output of the receiver through a step-up transformer with a voltage transformation ratio of about 10. You can do otherwise by connecting the horn capsule directly to the anode circuit of the VL6 lamp. This is how they were connected to receivers in the 20s and 30s. To do this, the output transformer T2 is removed and terminals XT3 and XT4 are replaced with a 6 mm "Jack" socket. The wiring of the socket and plug of the horn cord must be done so that the anode current of the lamp, passing through the coils of the horn capsule, enhances its magnetic field permanent magnet.

Antique radios were once very popular. Today, decorating a room more and more often cannot do without these items. It turns out they can decorate modern home. How? Judge for yourself. Today this is our story.

Significance old radio equipment in the setting modern house The fact is that previously it not only performed its main function, but also decorated the interior.

The photo shows the work of the Optimise Design company; they added an antique radio to the toilet, which became the finishing touch to the work.

Previously, radio devices were manufactured with a safety margin. And it is not surprising that they have survived to this day. Their popularity is growing. This can be judged by the number of fans who gather at the annual auctions for their sale.

The Mission Homepossible collection demonstrates a wide range of radio designs.

Everyone loves vintage accessories. And antique receivers attract with their charming design. Like old cars, they differ from each other in their appearance. It was only in the late 60s that their production became widespread and the differences between them became less clear.

At the show of old models from Avocado Sweets Interior Design Studio, I wanted to dance a jive to the rhythm of the last century. Their prices are rising. Small radios sell for $100, while rarer radios sell for $1,500 or $5,000.

Collectibles from the 1930s and 1940s range from $230 to $3,000, with some going for as much as $15,000. And when they were brand new, they sold for $20 apiece.

Appearance attractive to them. But nostalgia also plays an important role. Once upon a time it was a regular radio. Today, hobbyists buy it for $230 to build a collection of radio items from their childhood and youth.

Please note: whether this model will be in the bedroom from Robertson Lindsay Interiors or not, it is striking in its unusual design.

Radio tape recorders of the 80s were inexpensive. Perhaps for this reason, when broken, many ended up in landfills and have become rare these days.
When this house was being built by Natural Balance Home Builders, someone found boxes of radio equipment. The owner of the boxes turned out to be a far-sighted collector and has preserved the find to this day.

An adoration of the past is compatible with a love of modern technology. The result is a slew of MP3 players that emulate older models, including this unit from Areaware Magno Large Wooden Radio in the Bedroom by Richard Bubnowski Design.

Please note: how wonderfully old radios emphasize the retro style in the interior.

And people who want to buy classic equipment for their family are encouraged to visit the new California Historical Radio Society Museum in Alameda, California, or visit online auctions.

Antique radios are varied in design.

Decide which ones interest you. And after making a purchase, you will understand their significance in our history and culture.

Material kindly provided by Mary Jo Bowling.

Construction of the building

To make the body, several planks were cut from a sheet of treated fiberboard 3mm thick with the following dimensions:
— front panel measuring 210mm by 160mm;
- two side walls measuring 154mm by 130mm;
— upper and lower walls measuring 210mm by 130mm;

— rear wall measuring 214mm by 154mm;
— boards for attaching the receiver scale measuring 200mm by 150mm and 200mm by 100mm.

The box is glued together using wooden blocks using PVA glue. After the glue has completely dried, the edges and corners of the box are sanded to a semicircular state. Irregularities and flaws are puttied. The walls of the box are sanded and the edges and corners are sanded again. If necessary, we putty again and sand the box until flat surface. We cut out the scale window marked on the front panel with a finishing jigsaw file. Using an electric drill, holes were drilled 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 (automotive primer in aerosol packaging) in several layers until completely dry and smooth out the unevenness 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 with inside front panel. Finally, we try on the back wall and install the necessary connectors on it. We attach plastic legs to the bottom using double tape. Operating experience has shown that for reliability, the legs must either be firmly glued or fastened with screws to the bottom.

Holes for handles

Chassis manufacturing

The photographs show the third chassis option. The plate for fastening the scale is modified to be placed in the internal volume of the box. After completion, the necessary holes for the controls are marked and made on the board. The chassis is assembled using four wooden blocks with a cross-section of 25 mm by 10 mm. The bars secure the back wall of the box and the scale mounting panel. Posting nails and glue are used for fastening. A horizontal chassis panel with pre-made cutouts for placing a variable capacitor, 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

prototyping did not work for me. During the debugging process, I abandoned the reflex circuit. With one HF transistor and a ULF circuit repeated as in the original, the receiver started working 10 km from the transmitting center. Experiments with powering the receiver with a low voltage, like an earth battery (0.5 Volts), showed that the amplifiers were insufficiently powerful for loudspeaker reception. It was decided to increase the voltage to 0.8-2.0 Volts. The result was positive. This receiver circuit was soldered and, in a two-band version, installed at a dacha 150 km from the transmitting center. With a connected external stationary 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 went into self-excitation mode, which forced the device to be adjusted depending on the air temperature in the room. I had to study the theory and make changes to the scheme. Now the receiver worked stably down to a temperature of -15C. The price for stable operation is a reduction in efficiency by almost half, due to an increase in the quiescent currents of transistors. Due to the lack of constant broadcasting, I abandoned the DV band. This single-band version of the circuit is shown in the photograph.

Radio installation

Homemade printed circuit board receiver is made according to the original circuit and has already been modified in field conditions to prevent self-excitation. The board is installed on the chassis using hot melt adhesive. To shield the L3 throttle, an aluminum shield is used connected to common wire. The magnetic antenna in the first versions of the chassis was installed in the upper part of the receiver. But periodically they put it 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. The KPI with an air dielectric is installed using screws on the scale panel, and the volume control is also fixed there. The output transformer is used ready-made from a tube tape recorder, I assume that for replacement Any will do transformer from a Chinese power supply. There is no power switch on the receiver. Volume control is required. At night and with “fresh batteries,” the receiver begins to sound loud, but due to the primitive design of the ULF, distortion begins during playback, which is eliminated by lowering the volume. The receiver scale was made spontaneously. The appearance of the scale was compiled using the VISIO program, followed by converting the image into a negative form. The finished scale was printed on thick paper laser printer. The scale must be printed on thick paper; in case of temperature and humidity changes, office paper will go in waves and the previous appearance will not be restored. 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 burnt-out Chinese transformer. The arrow is fixed on the axis with glue. The tuning knobs are made from soda caps. The handle of the required diameter is simply glued to the lid using hot glue.

Board with elements

Receiver assembly

Radio power supply

As mentioned above, the “earthen” power option did not work. It was decided to use dead “A” and “AA” format batteries as alternative sources. The household 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” format battery from September to May. Especially for power supply from AA batteries back wall container is glued. Low current consumption requires powering the receiver from solar panels of garden lights, but for now this issue is irrelevant due to the abundance of “AA” format power supplies. The organization of power supply with waste batteries was what gave rise to the name “Recycler-1”.

Loudspeaker of a homemade radio receiver

I do not advocate using the loudspeaker shown in the photograph. But it is this box from the distant 70s that gives maximum volume from weak signals. Of course, other speakers are also suitable, but the rule works here - than more topics better.

Bottom line

I would like to say that the assembled receiver, having low sensitivity, is not affected by radio interference from TVs and pulse sources power supply, and the quality of sound reproduction differs from industrial AM receivers cleanliness and saturation. During any power failures, the receiver remains the only source for listening to programs. Of course, the receiver circuit is primitive, there are circuits of better devices with economical power supply, but this homemade receiver works and copes with its “responsibilities”. Spent batteries are properly burned out. The receiver scale is made with humor and gags - for some reason no one notices this!

Final video

A homemade receiver always works better. His music is more soulful to listen to, and even the news and weather always make me happy. Why is that? Don't know.

Turn the volume control, the power transformer clicks and shudders. There is complete silence for several seconds. Finally, at the base of the radio tubes, red dots, these filaments, flare up. They are already clearly visible at the top of the glass flasks. In a dimly lit room, a structure resembling an alien city comes to life. The growing noise in the speakers is clogged with foreign speech and music. How long ago it was. Perhaps it will be tomorrow.

It is desirable that some part of the receiver be made according to a direct amplification circuit , because this is history itself, all radio amateurs started with such designs, initially radio receivers were assembled according to this scheme. And there must be a medium wave range, with its maximum availability at night and evening time It can receive stations from Europe. Of course, the range on short waves is better, but I don’t want to complicate everything. It just so happens that medium and short waves are the main source of mobile information, which has never let me down. On these bands, I previously learned about the Chernobyl accident and the events in Moscow in 1991, when the VHF band froze, transmitting classical music.

It's decided it will be medium wave range, the path of this range itself will be executed according to type 3 direct amplification circuit -V - 2. For two centuries, I have been haunted by the dream of making a direct amplification receiver that works no worse than a superheterodyne type receiver. With the advent of some modern materials it became possible, although labor-intensive, but the latter never stopped me, this is what creativity is all about. The circuit for the high-frequency part will be made using transistors, and the low-frequency amplifier will be made using a combined lamp (two lamps in one bulb).

There is no way to do without high-quality music programs with frequency modulation. Therefore, there will definitely be an FM band (88 – 108) or the former domestic VHF band. For simplicity, you can use a ready-made superheterodyne high-frequency unit from a pocket receiver by connecting the output of its frequency detector to a low-frequency tube amplifier, but you can also take the difficult path, we’ll decide along the way.

Thus, in one package you will get a medium-wave direct amplification receiver using transistors, an FM superheterodyne made on a microcircuit, and a general tube sound amplifier. No one will see the transistors and microcircuits, only the radio tube will catch the eye, and, demonstrating the design, I will say:

Look, they knew how to do it before, just one radio tube, and how many stations it receives! And what a sound! Just listen...

Let's get started first part of the project.

Three-stage selective high-frequency amplifier.

Scheme.

A special feature of the circuit is the presence of tunable circuits in all three high-frequency amplification stages. Here, a three-section variable capacitor block from an old radio is fully used. But it was still not enough for the input circuit, and therefore the preselector is broadband, consists of a concentrated selection filter, made on a ferrite rod, which is also the magnetic antenna of the receiver. Initially, I wanted to abandon the magnetic antenna and use only an external one, as in the old designs. But today, practice has shown that it is impossible to do without a magnetic antenna, which has a radiation pattern and, therefore, is capable of cutting off unnecessary interference. Wired Internet, cell phone chargers, cheap voltage converters of others electronic devices completely “kill” the mid-wave range with their emissions at these frequencies.

Each stage operates in a mode that provides a stable gain, thanks to the use of negative feedback, a cascode circuit for switching on the second stage, incomplete inclusion of the circuits and the presence of resistors in the collectors of the transistors, dampening their gain and reducing the mutual influence between them during the tuning process, as well as separate additional filters on nutrition. Experience shows that a multistage tunable high-frequency amplifier is prone to self-excitation and unstable operation, and therefore all measures have been taken, in my opinion, to ensure normal operation of the amplifier.
Structurally, each amplifier stage is covered with a screen, and each coil is made in a screen, and the screen itself is made in the form of a coil, to emphasize the retro style.

Sketch of the coil in the screen.

To test the high-frequency amplifier, an external power supply of 3 to 9 volts is used. As a low-frequency amplifier, you can connect an amplifier based on the TDA 7050 microcircuit, which is in the article “High-impedance telephone for a detector receiver.”
Immediately the result was receiver 3 - V -1.

Adjustment.

The receiver will work immediately, but needs a little adjustment. Having tuned to a radio station in the upper part of the range, we achieve maximum volume with subscript capacitors, and at the bottom of the range we fix pieces of ferrite with a compound next to the coils at the maximum reception volume.

If the receiver is unstable and prone to self-excitation, then it is necessary to increase the values ​​of resistors R5; 9;11 -13, or the value of capacitor C13, or add such a capacitor to the following stages.

After adjustment, I measured the receiver bandwidth at three decibels. At the bottom of the range it turned out to be 15 kilohertz, at the top 70 kilohertz. The sensitivity from the input from an external antenna is no worse than 200 microvolts and 20 microvolts in range, gradually improving with increasing frequency, which corresponds to the receiver of both the third and upper classes, according to
GOST 5651-64.

In order not to upset myself, I decided not to measure selectivity (selectivity) on the adjacent channel. The acuity of sensations remained for field tests. I decided to just make sure how two powerful radio stations would be received:

1. RTV - Moscow region 846 kHz, 75 kW, 40 km from the test site.

2. Radio of Russia 873 kHz, 250 kW, more than 100 km.

After all, the separation between them is only 26 kHz. The first radio station is heard perfectly, there are no gaps in the neighboring station. When listening to the second radio station, the rating is four; if you listen, you can hear the gaps from the first. This is the most unpleasant place in the entire receiver.

Radio Liberty is confidently received with a transmitter power of 20 kW, located more than 130 km from the site. In the evening the range comes to life, radio stations from Ukraine and Belarus are received.

Tuning into radio stations is qualitatively different from superheterodyne receivers, since there is no noise between stations. If the turned on receiver is not tuned to a station, then it seems that it is not working.

Why I did all this, I don’t know. It’s just that now I have a radio receiver in one single copy, with a unique design, with a soulful sound, with memories of childhood and youth.

To be continued, we still have to assemble a tube amplifier.

Addition. September 2012.

Magnetic antenna on a ferrite rod.