Once upon a time we assembled our first simple radios in school age from sets. Today, due to the development of modular design, it is not difficult to assemble a digital radio receiver even for people who are extremely far from amateur radio. This receiver's design is based on the impressive 1935 AWA radio that the author came across in the book Deco Radio: The Most Beautiful Radios Ever Made. The author was so impressed by its design that he wanted to have his own analogue.
The design uses a Nokia 5110 LCD display to display the frequency and an encoder to select it. The volume is controlled by a variable resistor built into the amplifier. To emphasize the design, the author also used an Art Deco style font to display information on the display. The Arduino code contains a function for remembering the last station listened to (which was listened to for more than five minutes).
Step 1: Components
- Arduino Pro Mini
- FTDI programmer
- TEA5767 FM radio module
- Speaker 3W
- PAM8403 amplifier module
- Encoder
- Nokia 5110 LCD display
- Battery charge and protection board
- 18650 battery
- Holder 18650
- Switch
- Breadboard 5x7 cm
- Connecting wires
- Speaker fabric
First of all, if you don't have great experience When working with Arduino, you should first assemble the circuit using a non-printed breadboard. In this case, for convenience, you can use Arduino Nano or UNO. Personally, at the stage of debugging circuits, I use Arduino UNO, since it, together with development board convenient to use for connecting the necessary components, practically without using soldering. When you turn on the device, the logo should be displayed on the screen for a few seconds, after which the frequency of the last listened station is loaded from the EEPROM memory. By turning the encoder knob you can adjust the frequency by changing stations.
When everything works well on the breadboard, you can move on to the main assembly, using the more compact and cheaper Arduino PRO Mini, which, moreover, has lower consumption. But before that, let's see how everything will be located in the case.
Step 3: Design the Case
The 3D model was developed in the free but quite powerful Fusion 360 program.
Step 4: 3D Printing and Processing
FormFutura "wooden" plastic was used for printing. This is a rather unusual plastic, the peculiarity of which is that after printing the parts have a look similar to wood. However, when printing with this plastic, the author encountered a number of problems. Small parts They printed without problems, but the body, the largest part, did not print the first time. When trying to print it, the nozzle constantly became clogged, the situation was aggravated by regular power failures, which is why the author even had to purchase a UPS for the printer. Ultimately, the body was printed on top of the unprinted blank. This solution, however, is not really a solution to the problem, just a one-time way out of the situation, so the question remains open. Since the print did not work out successfully, the author then decided to sand the body, putty it with wood putty and varnish it. Yes, this plastic doesn’t just look like wood, it’s essentially fine wood dust mixed with a binder plasticizer, so the parts printed with it are practically wooden and can be processed using ordinary wood.
Step 5: Putting it all together
The next step is to install the electronics into the housing. Since everything has already been modeled in Fusion 360, this won't be a problem. As you can see, each component has its own position in the case. The first step was to unsolder the Arduino Pro Mini, after which the code was loaded into it. The next step is the power source. The project used a very convenient and compact Wemos board, which is simultaneously responsible for charging the battery, protecting it, and also increases the voltage for consumers to the required 5 volts. Instead, you can use a conventional charge and protection module, and increase the voltage with a separate DC/DC converter (for example TP4056 + MT3608).
Next, the remaining components, speaker, display, and amplifier are soldered. Also, even though there are power supply capacitors on the amplifier module, it is advisable to add another one (the author set it to 330 uF, but 1000 is also possible). The sound quality (if 10% THD can be called quality) of the sound of the PAM8403 amplifier very much depends on the power supply, as does the operation of the radio module. When everything is soldered and tested, you can start final assembly. First of all, the author glued the grille and radio fabric on top of it.
Push. Radio fabric is a specific thing, and every stall does not sell it. However, in every women's needlework store you can buy such a thing as canvas (fabric for cross stitch). It is inexpensive and very suitable as a replacement for radio fabric; it comes in different colors. Take natural (not synthetic) and with the largest cell. By the way, it fits perfectly with the design of this radio.
All other boards are secured in place using hot-melt adhesive. You can use hot glue a lot, but it works really well for these purposes, considering that most modules do not have mounting holes. Although I prefer to use double-sided "car" tape for these purposes.
Step 6: Firmware
This step should have been placed higher, since it needs to be flashed at the debugging stage. The basic idea of the code is this: when the encoder knob is turned, the frequency is searched, when the encoder knob remains in the same position for more than 1 second - this frequency is set for the FM receiver module.
If(currentMillis - previousMillis > interval) ( if(frequency!=previous_frequency) ( previous_frequency = frequency; radio.selectFrequency(frequency); seconds = 0; )else
The FM radio module takes about 1 second to tune to a new frequency, so it will not be possible to change the frequency in real time by turning the encoder knob, because in this case, the tuning of the receiver will be very slow.
DIY steampunk radio. Let's continue the topic of the second life of outdated gadgets. At one time, FM radios with simple electronic settings consisting of two buttons “Scan” and “Reset” were popular. Such a receiver can become the basis for an interesting design of a loud-speaking receiver, very suitable for use in the workplace, thanks to its compact size and local voice-over of the workplace. The most difficult part of being a radio amateur is not always making electronic filling, but the production of a strong and successful case for housing the soldered item. To give the receiver a second life, an attempt was made to make a case in the steampunk style. See what came out of this below.
How to make a steampunk hull
Please do not judge strictly - this is the first attempt. In addition to developing a stylish housing for the radio, the goal was to minimize costs and use available components and materials. Moreover, the materials are easy to process.
Before starting work, let's study the receiver's controls, which will need to be placed on the body. As mentioned above, these are two tuning buttons “Scan” - tunes the station after each press from the last radio station to the next radio station higher in the range. When tuning to the latest radio station, returning to the beginning of the range is done by pressing the “Reset” button. In the original receiver, the third button turns on the flashlight (it was not an LED, but a light bulb!) and is not used in this design. The volume of receiving stations is regulated by a potentiometer combined with the power switch. sound signal goes to the headphones, of course there is no speech in any stereo signal in such a receiver. The headphone cord is also an antenna for the radio. Controls can be purchased at a store or used from old equipment. IN this design controls were purchased, the total price of two buttons, a switch, an antenna terminal and a potentiometer (30 kOhm) with a knob did not exceed 150 rubles (2013). A sensitive loudspeaker extracted from a small-sized speaker was used as a loudspeaker. Head resistance 8 ohms.
Column - donor 
Speaker 1. The body is based on a piece of white polystyrene sheet measuring 200x130 mm and 1.5 mm thick. The sheet contains markings for controls and body bends to form side walls with a height of 40 mm. Possible options for using plastic housings distribution boxes purchased at an electrical goods store.
2. C inside According to the marking of the bend of the walls, small cuts are made, for example, with the sharp end of scissors or a knife, 1/4 - 1/3 of the thickness of the plastic.
3. Gas lighter evenly heat the entire bend until the plastic softens and form side wall. The flame should not reach the bend point 10-15 mm. This will result in the most intense heating. We perform the same operation with the second wall. The resulting “U”-shaped body should rest with all ends of the side walls on the surface.
Body parts 
Marking the workpiece 
4. After making the body, you can make holes. The sound from the speaker will be transmitted towards the listener through the bell. A siphon was used as a socket to remove water from the floor (made in Spain :)). Hole for speaker - bell can be drilled thin drill and then trim with a knife.
5. The front and back walls are cut out with your own hands using tailor’s scissors, also from sheet polystyrene and glued with glue for gluing plastic models.
6. We process the gluing seams with fine sandpaper to smooth out the edges.
7. The drain is made of an unknown plastic and it was not possible to glue it. To maintain the style, the included threaded clamp was used, which was attached to the body with hot-melt adhesive from the inside. At the same time, we secure the loudspeaker with hot glue.
Holes in the housing 
The clamp is secured 
Receiver body 8. We install control elements into the resulting housing. We use from the old receiver battery compartment, from which we remove unnecessary plastic.
9. Using a soldering iron, carefully remove the potentiometer from the receiver board and solder the extension conductors for:
— setting buttons;
- loudspeaker;
— volume control potentiometer;
— power switch;
— power supply for the receiver, minus to the switch, plus to the battery compartment;
— antennas, it is better to wrap the antenna wire around a pencil and place it, slightly stretched, in the receiver body, so you may not need to connect an external antenna.
10. Solder the conductors to the controls. We insert the batteries. We check the operation of the receiver; if there is no mistake anywhere, the electronics will work immediately.
11. Secure the board, battery compartment and antenna inside the case with hot glue. Look at the photo. Cut out the bottom cover from corrugated cardboard. Retro radio ready.
The board is connected 
Receiver basement 
Within the city limits, the radio receiver receives almost all stations; in the suburbs, the number of received stations may decrease and you will need to connect an external antenna; a piece of wire up to a meter long should be enough. Do not expect high volume from the receiver; if you need to increase the volume, you need to build in an amplifier. An example of an amplifier is given
My friend asked me to build a simple radio for him with his own hands in a certain theme. He looked at several options I suggested, and we agreed on the theme of Guinness beer.
Guinness is an Irish draft beer, its emblem is a golden harp. We decided that the central place in the design of the radio would be given to this harp, and we decided to omit the text.
After drawing several sketches, we came to the conclusion that the most successful shape was the “tombstone” shape. Having chosen a shape, we began to design and assemble a vintage MP3 radio.
One of the main tasks was the built-in subwoofer. I used the speakers from 2.1 computer speakers, I ordered the MP3 module on eBay.
List of materials used for a homemade radio:
- computer speakers 2.1
- power supply 12V 1A AC-DC (for MP3 module) - step-down converter
- mp3 decoder
- rotary switch (for lamps)
- FM antenna (built into the MP3 module)
- gold caps for volume, bass and power switches
- gold foil and glue
- two-way adhesive tape on a foam base, wires and various auxiliary materials
Step 1: Design and Assembly
Since I disassembled the speakers to get the speakers out of them, I know what the internal volume of the subwoofer in the radio needs to be made, and based on this, calculate the dimensions of the radio housing.
I sketched it in Sketchup to work out the model and get the dimensions of the parts. Unfortunately, I did not find the software model, so I could not attach it to the article.
When the contours of the parts are applied to the wood, cut out the parts with a jigsaw or openwork saw.
I always cut out the parts with a margin so that I can sand off the excess wood to get the shape out.
I made the front panel larger than the back wall so that the place where the radio housing was attached to the front panel was not visible.
The subwoofer speaker is enclosed in an inner box and is carried out through a hole in back wall. I left the original cardboard tube from a computer speaker.
Step 2: Milling
When the parts you cut out are polished and brought to the right sizes, you can begin to mill the parts to complete their appearance and to assemble the product.
In the front panel, on the inside, you need to machine a groove into which the radio housing will be attached; we mill the back wall to create an overlapped joint to make the connection between the back wall and the housing invisible.
We process the edges of the internal hole and the base of the receiver in the front wall with a cutter with an S-shaped profile. The outer edge of the front panel is simply rounded.
One of the tasks in the manufacture of the radio receiver was sufficient endurance - the housing must withstand the load of a working subwoofer.
I processed the edges of the box parts with a straight router attachment so that they overlap. I glued the joints, and additionally fastened the parts with nails without heads.
Because of vent The subwoofer comes out through the back wall, the ventilation tube had to be placed in a box, so I cut out the place for gluing the subwoofer with a straight bit for a router.
Step 3: Decorative Lattice
The inside of the front panel will need to be ground down to a thickness of 3 mm with a router so that the decorative grille can be installed flush with the rear surface of the panel. To do this I again used the straight router bit.
I cut out the pattern of the decorative lattice in a larger contour around the perimeter; the pattern from the template was transferred to the wood with an X-acto knife.
The contour of the harp is cut from oak plywood on jigsaw machine. To make thin strips of string I used a nail file.
Step 4: Install the electrical wiring
Show 5 more images
Before fixing all the components in place, you need to perform a test assembly. After all the glued joints have dried, the wood must be covered with stain and finishing compound.
Using a straight cutter, cut out holes for the on/off, volume and bass knobs.
Make two plywood boards - one to cover with fabric (it will serve as a background for the harp) and the second to attach the speakers to the decorative grille. Attach the MP3 module to the grille with screws.
Now you need to connect all the components to each other, power from the converter to the amplifier, power from the adapter to the MP3 module, connect the MP3 module to the amplifier, to the speakers and the FM antenna to the MP3 module.
The converter is quite heavy, so I screwed it to the cover of the amplifier box; I attached the rest of the circuits to the cover of the amplifier box on double-sided foam adhesive tape.
Step 5: Cover the wood with stain and cover the harp with foil
The base, front panel and rear wall are covered with two thin layers Minwax stain and three very thin layers of polyurethane primer.
Cover the decorative grille with black spray paint. After covering the harp figure with glue, place a sheet of foil on top. Using a wooden ice cream stick (or other tool with a smooth edge), smooth out the foil so that it sticks well. We lift the sheet, now we can see that the harp on the grille is covered with gold metal. Just in case, I coated the harp with a layer of primer to prevent the foil from peeling off.
Before gluing the foil, make sure that the surface of the adhesive is smooth - the foil will show the slightest unevenness. The photo shows that the foil on the harp emphasizes the rough texture of the surface underneath.
Step 6: Pine Veneer Cladding
Due to the fact that my retro receiver has a subwoofer and is quite large in size, I decided that it needed to add a horizontal tie between the front panel and the back wall. I processed the edges of this bundle with a milling cutter so that the parts of the body were attached to it overlapping.
After that I decided to add side pieces to the receiver body. The pieces of wood for the rounded segments of the body have cuts on the inside and with the help of a soap solution (soak for about 20 minutes) they can be bent and installed in place. I additionally glued the places where they were attached to the walls and secured them with nails without a head.
When the body assembly is completed, we unroll the veneer so that it can “rest.” After this, we glue the veneer around the perimeter of the body (I used adhesive-based veneer) and cover masking tape already treated areas of wood, and in the same way we cover the veneer with two layers of stain and three layers of primer.
Remove the masking tape and the radio is now ready.
Construction of the building
To make the body, several boards 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, putty again and sand the box until a smooth surface is obtained. 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 scale window glass from thin plexiglass and carefully glue it to the inside of the 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 handlesChassis 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 are 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 inductor, an aluminum shield connected to a common wire is used. 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 any transformer from a Chinese power supply will be suitable for replacement. 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. Appearance 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. Pen required diameter Simply glue it to the lid using hot glue.
Board with elements Container with batteries
As mentioned above, the “earthen” power option did not work. As alternative sources It was decided to use dead “A” and “AA” format batteries. 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. A container is specially glued to the back wall for power supply from AA batteries. Low current consumption requires the receiver to be powered from solar panels garden lanterns, but for now this issue is irrelevant due to the abundance of “AA” format power supplies. The organization of power supply with waste batteries led 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 will do, but the rule here is that the bigger the better.
Bottom line
I would like to say that the assembled receiver, having low sensitivity, is not affected by radio interference from TVs and switching power supplies, 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
Today we will analyze the TOP 3 working circuits of tube receivers of the HF, VHF, FM bands. First of all, let's look at how to assemble a simple tube HF receiver. The second project is a retro-style VHF FM receiver. According to the third scheme, we will assemble a low-voltage tube super-regenerative FM receiver without an output transformer.
DIY tube HF receiver
First, let's look at an interesting HF receiver circuit. This radio receiver is very sensitive and selective enough to receive shortwave frequencies around the world. One half of the 6AN8 tube serves as an RF amplifier and the other half as a regenerative receiver. The receiver is designed to work with headphones or as a tuner followed by a separate bass amplifier.
Circuit diagram of a tube HF receiver
For the body, take thick aluminum. The scales are printed on a sheet of thick glossy paper and then glued to the front panel. The winding data of the coils is indicated in the diagram, as well as the diameter of the frame. Wire thickness - 0.3–0.5 mm. Winding turn to turn.
For the radio power supply, you need to find a standard transformer from any low-power tube radio, providing approximately 180 volts of anode voltage at a current of 50 mA and 6.3 V filament. It is not necessary to make a rectifier with a midpoint - a regular bridge will suffice. Voltage spread is acceptable within +-15%.
Setup and Troubleshooting
Tune to your desired station using variable capacitor C5 approximately. Now with capacitor C6 - for precise tuning to the station. If your receiver does not receive normally, then either change the values of resistors R5 and R7, which generate additional voltage at the 7th terminal of the lamp through potentiometer R6, or simply swap the connections of pins 3 and 4 on the coil feedback L2. The minimum antenna length will be about 3 meters. With a conventional telescopic one, reception will be rather weak.
Low-voltage tube super-regenerative FM receiver without output transformer - circuit and installation
Consider a tube design with low plate voltage, very simple circuitry, common components, and no need for an output transformer. Moreover, this is not just another headphone amplifier or some kind of overdrive for a guitar, but a much more interesting device.
Superregenerators are a very interesting type of radio receiver, which is distinguished by its simplicity of circuits and good characteristics, comparable to simple superheterodynes. Subzhi were extremely popular in the middle of the last century (especially in portable electronics) and they are intended primarily for receiving stations with amplitude modulation in the VHF range, but can also receive stations with frequency modulation (i.e. for receiving those same ordinary FM stations).
The main element of this type of receiver is a super-regenerative detector, which is both a frequency detector and a radio frequency amplifier. This effect is achieved through the use of controlled positive feedback. There is no point in describing the theory of the process in detail, since “everything was written before us” and can be mastered without problems using this link.
This scheme was taken as a basis:
After a series of experiments, the following circuit was formed using a 6n23p lamp:
This design works immediately (with correct installation and a live lamp), and produces good results even on ordinary in-ear headphones.
Now let's take a closer look at the elements of the circuit and start with the 6n23p lamp (double triode):
To understand correct location legs of the lamp (information for those who have never dealt with lamps before), you need to turn it with the legs towards you and the key down (the sector without legs), then the beautiful view that appears before you will correspond to the picture with the pinout of the lamp (works for most other lamps ). As you can see from the figure, there are as many as two triodes in the lamp, but we only need one. You can use either one, it makes no difference.
Now let's follow the pattern from left to right. It is best to wind inductors L1 and L2 on a common round base (mandrel), a medical syringe with a diameter of 15 mm is ideal for this, and it is advisable to wind L1 on top cardboard tube, which moves with little effort along the body of the syringe, thereby adjusting the connection between the coils. As an antenna, you can solder a piece of wire to the outermost pin L1, or solder an antenna socket and use something more serious.
It is advisable to wind L1 and L2 with a thick wire to increase the quality factor, for example, with a wire of 1 mm or more in increments of 2 mm (special accuracy is not needed here, so you don’t have to worry too much about each turn). For L1 you need to wind 2 turns, and for L2 - 4–5 turns.
Next come capacitors C1 and C2, which are a two-section variable capacitor (VCA) with an air dielectric, it is perfect solution For such circuits, it is undesirable to use KPI with a solid dielectric. Probably, the KPI is the rarest element of this circuit, but it is quite easy to find in any old radio equipment or at flea markets, although it can be seen with two ordinary capacitors (necessarily ceramic), but then you will have to provide adjustment using an improvised variometer (a device for smoothly changing inductance). KPI example:
We need only two sections of KPI, they must be symmetrical, i.e. have the same capacity in any adjustment position. Their common precision will be the contact of the moving part of the KPI.
This is followed by a damping circuit made on resistor R1 (2.2 MΩ) and capacitor C3 (10 pF). Their values can be changed within small limits.
Coil L3 acts as an anode choke, i.e. the high frequency is not allowed to travel further. Any inductor (not on an iron magnetic circuit) with an inductance of 100–200 μH will do, but it’s easier to wind 100–200 turns of thin enameled copper wire around the body of a ground-off powerful resistor.
Capacitor C4 serves to separate the DC component at the output of the receiver. Headphones or an amplifier can be connected directly to it. Its capacity can vary within fairly wide limits. It is advisable that the C4 be film or paper, but ceramic will also work.
Resistor R3 is a regular 33 kOhm potentiometer, which serves to regulate the anode voltage, which allows you to change the lamp mode. This is necessary to more accurately adjust the mode to a specific radio station. You can replace it with a constant resistor, but this is not advisable.
This is where the elements end. As you can see, the scheme is very simple.
And now a little about the power supply and installation of the receiver.
Anode power supply can be safely used from 10V to 30V (more is possible, but it is already a little dangerous to connect low-impedance equipment there). The current there is very small and a power supply of any power with the required voltage is suitable for power supply, but it is desirable that it be stabilized and have a minimum of noise.
And further prerequisite is the lamp incandescent power supply (in the picture with pinout it is indicated as heaters), since without it it will not work. Here more currents are needed (300–400 mA), but the voltage is only 6.3V. Both alternating 50 Hz and constant voltage are suitable, and it can be from 5 to 7V, but it is better to use the canonical 6.3V. Personally, I have not tried using 5V on the filament, but most likely everything will work fine. The heat is supplied to legs 4 and 5.
Now about the installation. The ideal arrangement is to place all the elements of the circuit in a metal case with the ground connected to it at one point, but it will work without a case at all. Since the circuit operates in the VHF range, all connections in the high-frequency part of the circuit should be as short as possible to ensure greater stability and quality of operation of the device. Here's an example of the first prototype:
With this installation everything worked. But with a metal body-chassis it is a little more stable:
For such schemes the ideal is wall-mounted installation because it gives good electrical characteristics and allows you to make amendments to the circuits without much difficulty, which is no longer so easy and accurate with a board. Although my installation cannot be called neat.
Now about the setup.
After you are 100% sure that the installation is correct, you apply voltage and nothing explodes or catches fire - this means that the circuit most likely works if the correct values of the elements are used. And you will most likely hear noise in the headphones. If you don’t hear stations in all positions of the KPI, and you are sure that you are receiving broadcast stations on other devices, then try changing the number of turns of the L2 coil, this will adjust the resonance frequency of the circuit and perhaps get to the desired range. And try turning the variable resistor knob - this may also help. If nothing helps at all, then you can experiment with the antenna. This completes the setup.
Video about assembling a tube receiver:
Purely tube version (at the breadboard level):
Option with adding ULF to the IC (already with the chassis):
