How to make a radio at home. Simple radio. Regenerative transistor radios KP303

I tried to make this homemade VHF receiver in a "retro" style. Front End from the car radio. KSE marking. Further, the IF unit on the KIA 6040, the ULF on the tda2006, the 3GD-40 speaker, in front of which the 4-5 kHz rejector, I don’t know for sure, picked up by ear.

Radio receiver circuit

I do not know how to do digital tuning, so it will be just a variable resistor, for this VHF unit, 4.6 volts are enough for a complete overlap of 87-108 MHz. Initially, I wanted to insert an 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, the surge protector is installed, of course it does not hurt.

There was no suitable dial gauge, or rather there was, but it was a pity to install - only 2 remained, so I decided to remake one of the unnecessary М476 (as in Ocean-209) - I unbent the arrow, made a scale.

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

Scale under glass. Tuning knobs from some dump radio, tinted.

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

Since ready-made vintage cases in good condition are already difficult to get - I made a homemade replica, in our backwoods all the vintage has long since rotted in garages. Inspired by this photo:

Discuss the article HANDMADE RADIO RECEIVER IN RETRO STYLE

There are no different types of radios - large radios that are part of an even larger system, car radios, portable radios with headphones. Here is a very simple radio that you can assemble yourself using the materials at hand.

To make a homemade radio you need

6. Sharpen the pencil so that a long piece of lead sticks out. Break off the lead and attach it to the sharp end of the safety pin. Using a piece of wire, screw the lead to the pin. Using a pair of pliers, bend the head of the pin back so that it lies flat on the board.

7. Place the safety pin to the right of the blade so that the tip of the lead touches the blade. Place one of the nails in the head of the pin and hammer it into the board with a hammer until it almost touches the pin.

8. Connect the wire to the left button on the razor blade. Push in the button as hard as possible so that the exposed wire rests on the blade. Then take the other end of the wire and wind it around the nail to the left of the coil.

9. Attach the wire to the nail to the right of the coil. Take the other end of this wire and wind it around the end of the headphone wire.

10. Connect another wire to the second metal end of the headphones. Now take the other end of this wire and place it under the head of the nail holding the safety pin. Drive in the nail so that the pin pops up. Do not nail it too tightly, because you should be able to move the pin a little.

11. Attach another wire to the nail connecting the blade to the coil. This will be the antenna. The longer the antenna, the better. Let it hang from the window. Or even better, take a long wire, if you have one, and stretch it from the window to the tree.

12. Attach another piece of wire to the nail connecting the coil to the headphones. This will be your ground wire. You need to attach it to something that goes into the ground. The best grounding is this. Wrap the bare end of the wire around a pipe that only carries cold water.

13. Put on your headphones and don't make any loud sounds in the room where your homemade radio is installed. Use your finger to slowly move the pin so that a piece of lead passes over the blade. Very quiet, faint crackling sounds should be heard in the headphones. Keep moving the pin until you catch a station. Move the pin very slowly and listen very carefully. You can only catch the stations closest to you, and then they will be very quiet.

Upgrade your homemade radio

Want to upgrade your homemade radio and have better reception? This is possible if you buy a detector receiver from an electronics store and install it in place of the razor blade and safety pin kit. It works in a similar way, only instead of a razor blade -.

The simplest homemade blade radio described here is called a "trench" radio. During World War II, soldiers on the front lines (often in the trenches) made this kind of radio because all the details were at hand.

Despite the abundance of all kinds of mobile gadgets, larger equipment, many people with interest and genuine enthusiasm strive to make something with their own hands. And this is not surprising, because only new knowledge, work and ingenuity make us live and be on a constant path to self-development. This article is dedicated to those who are passionate about electronics and technology. Let's talk about how to make a radio yourself. We are talking about the rare model "Komsomolets", popular in Soviet times.

What needs to be prepared for work?

To make a radio receiver with your own hands, you need to find:

• A regular thread spool.
• PEL winding wire.
• Wave catcher (D2, D9).
• Head-mounted electromagnetic telephones.
• Constant capacitors.
• Clips with plug-in sockets.

Now the direct procedure is how to make a radio receiver with your own hands.

Frame base:

1. As a frame base, we use a spool-base from threads.
2. Wind a winding conductor (450 turns) around the coil, tapping every 80 turns.
3. Make bends by twisting the wire into loops.
4. Strip the taps and ends of the prepared spool.

Important! Spending a lot of time at the dacha in the summer season, you do not want to completely renounce civilization. To keep in touch latest news and events, to have the opportunity to relax while watching your favorite programs, it is not at all necessary to spend money on the purchase of special equipment. Find out which one will fit any type of TV.

How to make a radio with your own hands - assembling the receiver:

1. Connect one of the detector pins to the beginning of the coiled solenoid.
2. Connect one of the headset contact legs to the spool end.
3. Using a separate piece of wire, connect the leads of the phone and the wave catcher.
4. Connect the wire - this will be the antenna - to the wire that runs from the detector to the solenoid.
5. Strip the end of the antenna from a layer of insulating material.

Earthing

How to make a radio at home - figured out. Now screw the grounding cable to the wire between the headset and the end of the solenoid. This conductor will now be grounded. It is necessary so that you can experiment by switching between the solenoid pins when tuning the receiver.

Customization

After you have managed to assemble the radio, you need to make one more important step- customize it. To do this, hold your phones to your ears and watch for noises. If there is no noise, you need to tune the device to the radio wave. The essence of the setting is to change the number of turns in the antenna circuit.

Important! The detector radio is capable of receiving medium and long radio waves. You can also work on improving it so that the device can receive waves from remote stations.

How does a detector radio work?

From the antenna comes alternating current which converts the detector. Further, information is transmitted to the headphones in the form of sound waves. Tuning to a particular radio station is carried out by turning the knob. The antenna helps to pick up the signal from strong points nearby.

Important! Undoubtedly, low power is a design flaw. But there is also an advantage: such a device works without a power source. That's why he is a detector. If you decide not to waste time on assembling the device yourself, it may come in handy.

Video

As you can see, for someone who is really fond of assembling various electrical appliances, it will be very exciting to assemble a radio with your own hands. Moreover, the procedure is very simple and does not require complex actions.

Can a radio be assembled with less than 10 parts? Can a radio like this work without batteries?
Of course, this can be done quite simply: detector radios are not at all complicated and can work without batteries, receiving electricity from radio waves. In this article I will show you how you can collect do-it-yourself radio receiver without batteries, spending no more than an hour on the whole process!

What is good about a detector radio?
First, such a radio works without batteries. Secondly, all the parts necessary for its assembly cost about 10-15 rubles, and in old household electrical appliances they are in abundance. Thirdly, everyone can assemble a detector radio, regardless of their skills (reading and working with a soldering iron are welcomed)
But there are also disadvantages. Most likely, only one radio station with the strongest signal in your area will have good reception. The second drawback is low power. It will be enough to give more or less normal sound from a small earpiece, nothing more.
But still, such a receiver can come in handy in the country when there are power outages or it is problematic to buy batteries.

So let's start collecting battery-free radio!
Do we need to build?
Constant capacitor 190-500 PF
Capacitor 1000-2000 PF
Any diode (except light)
Copper wire with a diameter of 1-0.1 mm
Cylinder with a diameter of 10 cm (for example, a coffee can)
Newspaper
Metal peg about 30 cm long for grounding
Small speaker, for example from old headphones (radio phones)

This is how Oganov's detector radio circuit looks like:

We start with the simplest thing - grounding. We drive in a previously prepared metal peg into the ground, having previously fixed a wire on it (for safety reasons, it is better not to use a heating battery as a ground). And remember, the better the ground connection, the better your radio's reception will be. It is advisable to install grounding from the side of the house, where the sun gets the least, where the ground is always damp. We lead the free end of the ground wire into the house and attach it to the corresponding terminal of the radio receiver.

Then we create the antenna. I have it under the roof, about 10-12 meters long. You can make it from copper wire. Practice shows that with an antenna 10 m long, only one station will be received, but loudly. With an antenna length of 1-3 m, other stations can also be received, but they will be very hard to hear.
Next, we collect the coil. The coil consists of two equal parts, 20 turns each (this is for receiving medium waves, and for receiving long ones, you need to wind 60 turns). How to assemble a coil? Take something round with a diameter of about 10 cm (for example, a beer can), glue it over with a double layer of paper. The first layer is fixed to the jar with tape, the second is screwed onto the first. In this case, it will be easy to remove the spool after winding. Now we carefully wind the copper wire - turn to turn. Leave 5 centimeters of wire between the two parts of the coil, and do not forget to leave about the same amount of wire at the beginning and end. After you have wound the coil, it must be wrapped with electrical tape in two layers along the turns. And after removing it from the can, wrap it across. That's it, we don't need the newspaper anymore, we can get rid of it!

We start assembling a radio receiver that works without batteries!
The above scheme can be simplified to the following form:

In this form, it is easiest to assemble, and there will be less wires.
We carefully clean all the parts and solder them to each other according to the diagram! We attach the coil, antenna, grounding, earphone and, if you did everything correctly, we enjoy good and high-quality reception of our radio signal.
If you want to tune to a different frequency, or the reception quality does not suit you, assemble the coil from a thicker wire.
Tuning is done by moving one part of the coil relative to the other. For more precise tuning, you can take several variable capacitors that replace C1, by tuning them you can tune to the station as accurately as possible.
How your radio will look like - depends entirely on your imagination! Due to its small size, the receiver can be packed into any container.
I hope that this article will be useful to someone.

For a long time, radio receivers occupied one of the first places in popularity among other electronic designs. The emergence of new sound-reproducing devices, CD-players, tape recorders and the rapid development of computer technology have pushed radio reception technology out of the leading positions, without diminishing its importance.

Receivers are subdivided into detector, forward amplification, superheterodyne type, direct conversion, with positive feedback (regenerative, superregenerative), etc.

Simple two-transistor direct amplification radio receiver

A simple forward-gain receiver is shown in Fig. 1 [MK 10 / 83-11]. It contains a tunable input oscillatory circuit - a magnetic antenna and a two-stage bass amplifier.

The first stage of the amplifier is also an RF modulated signal detector. Like many similar simple direct amplification receivers, this receiver is capable of receiving signals from powerful, less distant radio stations.

The inductor is wound on a ferrite rod 40 mm long and 10 mm in diameter. It contains 80 turns of wire PEV-0.25 mm with a branch from the 6th turn from the bottom (according to the diagram).

Rice. 1. Scheme of a simple radio receiver on two transistors.

Reflex receiver Y. Prokoptsov

The radio receiver, designed by Yu. Prokoptsev (Fig. 3), is intended for reception in the medium-wave range [R 9 / 99-52]. The receiver is also assembled according to the reflex scheme.

Rice. 3. Scheme of a reflex radio receiver for the MW range.

The antenna is made of a piece of a 400NN ferrite rod with a length of 50 and a diameter of 8 mm. Coil L1 contains 120 turns of PELSHO-0.15 mm single-layer winding, and L2 contains 15 ... 20 turns of the same wire. Establishing the receiver is reduced to setting the collector current of the transistor VT2, equal to 8 ... 10 mA, using the resistor R2. Then the collector current of the transistor VT3 is adjusted within 0.3 ... 0.5 mA by selecting the resistor R4.

We will not consider superheterodyne receivers in this review. However, if desired, they can be obtained by combining a direct gain receiver (Fig. 1 - 3) and a converter (Fig. 10), or from a direct conversion receiver (Fig. 11).

Super-regenerative FM radio

A super-regenerative radio receiver has a high sensitivity (up to μV units) with sufficient simplicity. In fig. 4 shows a fragment of a circuit of a super-regenerative radio receiver E. Solodovnikov (without ULF, which can be made according to one of the previously given circuits - The simplest low-frequency amplifiers on transistors) [Rl 3 / 99-19].

Rice. 4. Diagram of a super-regenerative radio receiver E. Solodovnikov.

The high sensitivity of the receiver is due to the presence of deep positive feedback, due to which the gain of the stage, after turning on the radio receiver, rather quickly increases to infinity, the circuit goes into the generation mode.

So that self-excitation does not occur, and the circuit can work as a highly sensitive amplifier high frequency use a very original trick. As soon as the gain of the amplification stage rises above a certain predetermined level, it is sharply reduced to a minimum.

The graph of the change in the gain over time resembles a saw. It is according to this law that the gain of the amplifier is changed. The average gain can be up to a million. The gain can be controlled using a special additional sawtooth pulse generator.

In practice, they act more simply: the high-frequency amplifier itself is used as such a generator for a dual purpose. The generation of sawtooth pulses occurs at an ultrasonic frequency inaudible to the ear, usually tens of kHz. In order to prevent ultrasonic vibrations from penetrating to the input of the next ULF cascade, use the simplest filters that separate audio frequency signals (R6C7, Fig. 4).

Superregenerative receivers are usually used to receive high frequency (over 10 MHz) amplitude modulated signals. Receiving signals with frequency modulation is possible by converting frequency modulation into amplitude modulation and subsequent detection by the emitter junction of the transistor of the thus obtained amplitude-modulated signal.

Conversion of frequency modulation to amplitude modulation occurs if the receiver intended for receiving amplitude-modulated signals is not tuned accurately to the frequency of receiving a frequency-modulated signal.

With this setting, a change in the frequency of the received signal of constant amplitude will cause a change in the amplitude of the signal taken from oscillatory circuit: when the frequency of the received signal approaches the resonance frequency of the oscillatory circuit, the amplitude of the output signal increases, with distance from the resonant one, it decreases.

Along with the indisputable advantages, the "super-regenerator" circuit has a lot of disadvantages. These are low selectivity, increased noise level, dependence of the generation threshold on the receiving frequency, on the supply voltage, etc.

When receiving FM broadcasting signals in the FM range - 100 ... 108 MHz or sound signals from television, the L1 coil is a half-turn with a diameter of 30 mm with a linear part of 20 mm. Wire diameter - 1 mm. L2 has 2 ... 3 turns with a diameter of 15 mm from a wire with a diameter of 0.7 mm, located inside a half-turn.

For the 66 ... 74 MHz range, the L1 coil contains 5 turns with a diameter of 5 mm from a 0.7 mm wire with a pitch of 1 ... 2 mm. L2 has 2 ... 3 turns of the same wire. Both coils have no bobbins and are parallel to each other. The antenna is made of a piece of mounting wire 50 ... 100 cm long. The device is adjusted with potentiometer R2.

Regenerative transistor radios KP303

Regenerative receivers, or receivers using positive feedbacks, are not found in industrial developments. However, in order to master all possible options for the implementation of the receiving technique, it is possible to recommend that you familiarize yourself with the operation of two such devices designed by I. Grigoriev (Fig. 5 and 6) [Rl 9 / 95-12; 10 / 95-12].

Rice. 5. Scheme of a receiver for receiving AM signals in the HF, MW and LW ranges.

The receiver (Fig. 5) is designed to receive AM signals in the range of short, medium and long waves. Its sensitivity at a frequency of 20 MHz reaches 10 μV. For comparison: the sensitivity of the most advanced direct amplification receiver is about 100 times lower.

Rice. 6. Scheme of a simple regenerative radio receiver for the frequency ranges 1.5 ... 40 MHz.

The receiver (Fig. 6) is capable of operating in the 1.5 ... 40 MHz range. For the range of 1.5 ... 3.7 MHz, the L1 coil has an inductance of 23 μH and contains 39 turns of wire with a diameter of 0.5 mm on a frame with a diameter of 20 mm with a winding width of 30 mm. The L2 coil has 10 turns of the same wire and is wound on the same frame.

For the range 3 ... 24 MHz, the L1 coil with an inductance of 1.4 μH contains 10 turns of a wire with a diameter of 2 mm, wound on a frame with a diameter of 20 mm, with a winding width of 40 mm. The L2 coil has 3 turns with a wire diameter of 1.0 mm.

In the range 24 ... 40 MHz, L1 (0.5 μH) contains 5 turns, the winding width is 30 mm, and L2 has 2 turns. The operating point of the receivers (Fig. 5, 6) is set with the potentiometer R4.

VHF FM radio receiver on transistor GT311

To receive FM signals, you can use VHF direct conversion receivers with phase locked frequency. Such receivers contain a frequency converter with a combined local oscillator, which simultaneously performs the functions of a sync detector.

Rice. 7. Scheme of VHF FM radio receiver A. Zakharov for the frequency range 66 ... 74 MHz.

The input circuit of the device is tuned to the receive frequency, the local oscillator circuit is tuned to the receive frequency, halved. Signal conversion occurs at the second harmonic of the local oscillator, so the intermediate frequency is in the audio range. The diagram of A. Zakharov's receiver is shown in Fig. 7 [P 12 / 85-28]. For the frequency range 66 ... 74 MHz, frameless coils with an inner diameter of 5 mm and a winding pitch of 1 mm contain, respectively, 6 turns with a tap from the middle (I) and 20 turns (L2) of a PEV-0.56 mm wire.

Simple Direct Amplification Receiver with Loop Antenna

A simple medium-wave direct-amplified radio receiver assembled according to the traditional scheme by G. Shulgin (Fig. 8) has a loop antenna [R 12 / 81-49]. It is wound on a workpiece: a 56x56x5 mm plywood plate. The inductor L1 (350 μH) has 39 turns of wire PEV-0.15 mm with a tap from 4 turns from the bottom (according to the diagram).

Rice. 8. Diagram of a radio receiver with a loop antenna for the MW range.

Simple radio receiver with a field-effect transistor input stage

In fig. 9 shows a simple radio receiver G. Shulga (without ULF) with an input stage on a field-effect transistor [R 6 / 82-52]. The magnetic antenna and variable capacitor are used from an old radio.

Rice. 9. Simple radio receiver G. Shulga.

FM frequency converter circuit

Frequency converter-converter E. Rodionova, fig. 10, allows you to "transfer" signals from one frequency band to another frequency region: from 88 ... 108 MHz to 66 ... 73 MHz [Rl 4 / 99-24].

Rice. 10. Scheme of a converter from 88 ... 108 MHz to 66 ... 73 MHz.

The heterodyne (generator) of the converter is assembled on a VT2 transistor and operates at a frequency of approximately 30 ... 35 MHz. Coil I is made of 40 cm long winding wire wound on a mandrel with a diameter of 4 mm. The converter is adjusted by stretching or squeezing the turns of the coil L1.

Superheterodyne and Direct Conversion Receiver Input Circuits

Finally, in Fig. 11 shows a diagram of the input circuit of the simplest superheterodyne receiver, and Fig. 12 receiver with zero intermediate frequency - direct conversion receiver.

Rice. 11. Scheme of the converter V. Besedin.

Converter V. Besedin (Fig. 11) "transfers" the input signal from the frequency band 2 ... 30 MHz to a lower "intermediate" frequency, for example, 1 MHz [R 4 / 95-19]. If a signal with a frequency of 0.5 ... 18 MHz from the HHF is applied to the diodes VD1 and VD2, then at the output of the LC filter L2C3 a signal will be selected whose frequency f3 is equal to the difference between the frequency of the input signal f1 and twice the frequency of the local oscillator f2: f3 = f1-2f2 or Af3 = Af1-2f2.

And if these frequencies are multiples of each other (f1 = 2f2), Fig. 2, then an ULF can be connected to the output of the device and receive telegraph signals and signals with single-sideband modulation.

Rice. 12. Scheme of the converter on transistors.

Note that the diagram in Fig. 12 easily converts to the circuit in fig. 11 by replacing diode-connected transistors directly with diodes, and vice versa.

Sensitivity even simple schemes direct conversion can reach 1 μV. Coil L1 (Fig. 11, 12) contains 9 turns of PEV wire 0.51 mm, wound a turn to a turn on a frame with a diameter of 10 mm. Branch from the 3rd turn from the bottom.

Literature: Shustov M.A. Practical Circuitry (Book 1), 2003.