DIY detector radio receiver
Radio is the most reliable and easiest way to communicate at a distance (except for trained carrier pigeons). It doesn’t matter whether it’s someone’s voice on the air, it would be good if it turned out to be the meaningful crackle of someone’s spark radio transmitter, and not the ethereal noise of an approaching thunderstorm! Taking into account the peculiarities of the propagation of radio waves, one can judge how far away an intelligent creature is. Perhaps this will be the call sign of a radio beacon from an underground shelter.
So, in our imaginary misfortune, in the worst-case scenario, unsweetened conditions may form around us, so we may well formulate very stringent and critical requirements for the designed receiver:
Based on these requirements, we define the subject of our creativity - the Detector Receiver. Yes, these are the simplest and cheapest receivers that do not require any additional sources of electricity for their operation. The device of the detector receiver is so simple that it can be built without any knowledge in the field of radio engineering! If there are two or three powerful stations not far from the installation site of the detector receiver, then when receiving on the detector receiver it is very difficult to isolate the transmission of one of them so that the others are not audible at all, which is very beneficial for us, as seekers of at least some signal. The detector receiver requires no tubes or transistors and is always ready to use. There are quite a large number of detector receiver circuits, differing from one another in greater or less complexity, tuning methods, and varying degrees of selectivity. True, there are a number of disadvantages associated with this, which cannot be eliminated in a detector receiver. The detector receiver does not provide reception of distant radio stations. The most powerful radio stations can be heard on a detector receiver no further than at a distance of 600 - 800 km in the daytime, and then only if there is a very high receiving antenna.
Fig.1. Schematic diagram of a detector radio receiver
I will describe the main points of the principle of radio reception, so that your future design does not remain a secret black box for you until the end of your life. An alternating current is supplied to the antenna of the transmitting radio station from the radio transmitter, quickly changing its direction and magnitude. You should understand this from your high school physics course. Under the influence of such an alternating current, electromagnetic waves arise in the space surrounding the antenna or, as they say, radio waves are emitted into space. These radio waves propagate from the antenna of the transmitting radio station in all directions at the speed of light, i.e., at a speed of 300,000 km per second. Suppose that an announcer is speaking or an orchestra is playing in front of a microphone connected to a transmitting radio station. The microphone is connected to the transmitter in such a way that the sound vibrations of speech or music affecting this microphone control the strength of the radio waves emitted by the antenna, i.e. Radio waves emitted by the antenna of a transmitting radio station change in strength to the beat of the announcer's voice or the sounds of the orchestra. Part of the radio waves emitted by the antenna of the radio transmitter reaches the antenna of our receiver and causes (induces) in it the same alternating current that occurs in the antenna of the transmitter. Although this induced current will be immeasurably smaller in magnitude than the current in the transmitting antenna, it will also change in time with the voice of the person speaking in front of the microphone of the transmitting radio station.
In the detector receiver, the alternating induced currents coming from the receiving antenna are converted into currents that can directly affect the headphones. This task of converting currents is performed by the receiver detector. Any receiving antenna, even a small indoor antenna, is crossed by radio waves from a huge number of radio stations scattered across the globe. The task of any receiver is to select from this huge number of currents induced in the antenna the currents of only the radio station that you currently want to listen to. This is what you do by “tuning” the receiver. By rotating the radio tuning knob, you tune it to one or another radio station, sometimes located at a great distance from the receiving location. It is quite clear that in our case you can confidently receive only fairly powerful radio stations that are not too far away.
The detector receiver itself is very simple. Every detector receiver has an oscillating circuit, with the help of which the receiver is tuned to the wave of the desired station. The receiving antenna and grounding are connected to the oscillating circuit. In some detector receivers for the same purpose, the connection between the antenna and the oscillating circuit is carried out through a small capacitor. High-frequency electrical oscillations received by the antenna are isolated by the oscillating circuit if it is tuned to their frequency, and are eliminated if it is not tuned to them. Thanks to this, the broadcast of the radio station to which the circuit is tuned stands out from all the others. A detector circuit is connected to the receiving oscillatory circuit, into which the detector and the telephone are connected in series. High-frequency electrical oscillations received and isolated by the receiving circuit are branched into a detector circuit, where they are detected, turning into low-frequency (sound) oscillations. Currents of sound frequencies passing through the phone cause its membrane to vibrate, which reproduces the sound. For better operation of the receiver, a so-called blocking capacitor is connected in parallel to the phone.
Determining the required materials
In order to determine the necessary parts and materials, just look at the diagram of our receiver. I mentioned the word details, most of which will probably not be available. But you can also make parts yourself, without having special equipment and machines.
Let's take another look at the diagram (Fig. 1) from top to bottom and list all the elements of our radio receiver. The very first of them is an antenna, then an oscillating circuit coil, several oscillating circuit capacitors, a detector, a blocking capacitor, a headset, and grounding. Not so much if you have a radio parts store nearby. But let's count on the worst case scenario, when this store is not nearby. I will briefly describe each element of this design, and what material may be needed to make it yourself.
An antenna is a long wire from 30 to 100 meters long. And since this is a wire, we will need either a single piece of such a long wire, or pieces of various wires twisted together. It doesn’t really matter what metal it is made of, be it aluminum, copper, steel, etc., single-core, stranded. Take everything you can find. The main thing is that in total they are of the required length and are connected to each other securely so that they do not break off when pulled. When connecting individual pieces of wire, do not forget to first clean them with a knife to remove oxides and paint.
One more thing. The antenna must be somehow attached to a tall object. But it is not the wire itself that needs to be fastened, but through an insulator, which you also need to make yourself. Without an insulator, the antenna will work very poorly, especially in wet weather and during precipitation. The insulator can be made from an ordinary plastic bottle. So, you will need wires for the antenna, and a plastic bottle for the antenna insulator.
The oscillating circuit coil (L1) is the resonant element of the receiver, many turns of wire on a rigid frame. Wires will be required again, but not just any wires. Here you will need a small diameter wire of approximately 0.3 - 0.8 mm and enough to wind at least 100 turns on a rigid frame, for example, on a 50 mm plastic pipe from a sewerage system. If there is no solid wire for the coil, then it can also be assembled from segments. So, for a coil of oscillating wire you will need wires and a plastic frame with a diameter of about 50 mm.
Oscillatory circuit capacitors (Cn) are also a resonant element of the receiver and are used to tune the receiver. They need to be made in several pieces of different capacities. This part is not at all difficult to make. You need to stock up on foil (from sweets, chocolate, etc.), polyethylene (as a dielectric) and small pieces of wiring for installation.
Detector (VD1) - in our case, an element that selects a modulating signal (an announcer's voice, for example) from the received radio signal. This part is no more complicated than all the others. It is best to use a factory-made diode; in the worst case, you will have to make it yourself.
Blocking capacitor (Sbl) - restores the loss of the detected signal. With it, the receiver is noticeably louder. It will need to be manufactured in the same way as tuning capacitors. The material for its manufacture is exactly the same.
Grounding is the second half of the antenna, which means that a poorly assembled grounding will noticeably degrade the quality of the received signal. Pipes of water supply systems can be used as ready-made grounding if it is known that they definitely have good contact with the ground, somewhere along the main line. Well, if such a system does not exist, then one must be made. Bury a massive metal object in the ground, pre-attaching a wire to it that will stick out of the ground.
The headset is the door to the invisible world of radio signals, the interface of consciousness. It is almost impossible to make it yourself. I mean, to make a headset with exactly the characteristics that we need. The whole secret of the headset we need so much is that it is high-impedance. Its internal resistance must be at least 1600 Ohms. Its design includes a magnet, a metal membrane and a large amount of very thin wire. It is very difficult to assemble this by hand on your knee. Therefore, you will have to look for it. If you still can’t find such a headphone, you will have to use alternative options. In the second part of the article you will find material about what available parts can be used instead of a high-impedance dynamic headphone.
Search for material
Searching for antenna material
As I already noted, any tensile wires from any metal will be used for the antenna, as long as the end result is a wire of sufficient length. I outlined what length of wire should be the result in a separate part of the article. There are no special requirements for searching for material for making an antenna - you need to take whatever you can get your hands on. These can be fragments of electrical wiring of buildings, telephone routes, any installation conductors, coaxial television cables, trolleybus and tram routes. But the latter are quite heavy both for installation and for moving when you determine the direction to the signal source.
Search for material for insulator
The insulator must be made of any dielectric. I suggested using a plastic bottle. It doesn't matter what was in that bottle before. If you can’t find a bottle, you can use a plastic pipe, or even any plastic object. The main thing is that what you find can provide reliable insulation of the antenna wire from the object to which the antenna will be attached. Thus, there is no way for this object to become part of the antenna. Be smart and resourceful
Fig.2. Antenna Insulator Material
Finding material for the oscillating circuit coil (L1)
Wires will be required again, but of a certain diameter from 0.3 to 0.8 mm. The wires can be in varnish, silk, or plastic insulation - this does not interfere with the operation of the coil. It is best if the wire for the coil is solid, but if it is not possible to find such a wire, then you can use sections of conductors. The power wires will not come from the electrical wiring - they are too large in diameter. When searching, we need to pay attention to transformers, computer network routes, telephone routes - that’s where we can find what we need!
If you are unable to find high-quality wire for the coil or mounting parts, the wire found in the transformers is quite useful (Fig. 4). As a child, you probably saw scattered metal plates in the shape of the letter W or E. The transformer must be disassembled carefully so as not to damage the wire. The best tool for disassembling a transformer is a screwdriver. First, remove the metal bracket that secures the transformer plates to the winding frame. The plates must be removed; we will not need them in the future. After you take out the frame, remove the protective film from it. Then start unwinding the wire. Avoid knotting and twisting of the wire. Immediately wind the wire onto a pre-prepared mandrel. It is best to use a mandrel with a diameter of 3 cm or more and made of any material. It is recommended to fasten the coil obtained in this way with threads so that the wire does not unwind.
Now about the reel frame. I recommended using a 5 cm diameter plastic pipe, which can be found in the ruins of plumbing systems. But you can also wind the coil on any tubular dielectric frame with a diameter of about 5 cm, for example, on a glass bottle, a plastic bottle, as long as this bottle is not shaped, i.e. had a constant diameter along its entire length.
Fig.3. Plastic pipe for the frame of the receiver oscillating circuit coil
Search for material for capacitors (Sn, Sbl)
To make these parts, you will need foil and a material that will act as an insulator between the capacitor plates. Foil can be taken from chocolate wrappers, candies, metal-containing wrappers of other food products. This foil is quite flexible, which is what we need. Polyethylene bags, packaging material, dry writing paper, tracing paper, and food wrapping paper can be used as a dielectric. Newspapers and magazines are not suitable, since due to the composition of the printing ink, the dielectric properties will be poor.
Fig.4. Material for the manufacture of capacitors
Search for detector material (VD1)
In general, it will be great if you immediately find a semiconductor diode among the radio junk (Fig. 5). It will relieve you of the complex work of constructing a detector and save your time. With a ready-made factory diode, the receiver will operate louder than with a homemade one. Of course, diodes themselves do not lie scattered on the streets. They can be found on the boards of radios, tape recorders, and televisions. Carefully study the contents of the detected boards, since the diodes are small in size from 2 to 4 mm in length. The semiconductor element itself is usually enclosed in a glass housing. The case has marking stripes. In our case, the number and color of these stripes do not matter. Which side to connect the diode in the circuit of our receiver also does not matter - either side.
Fig.5. Detector - semiconductor diode
But if you don’t find such a diode anywhere, don’t despair - you can make it yourself. This is the purpose of our article - to provide you with the knowledge of how to make the necessary receiver components yourself. The design of a homemade detector is given in another section of the article. I can only tell you that you will need to find a simple pencil, a razor blade, a pin, several small nails, and a board for attaching the structure. Small nails can be obtained from wooden window frames and shoes.
Search for grounding material
If you do not have a suitable grounding connection at the location where the radio is installed (a section of the plumbing system, for example), you will need to find a large metal object to make the grounding yourself. It is better if this item is not painted, thereby ensuring reliable interaction with the soil. As grounding, you can use a metal bucket, a refrigerator body, a metal kitchen stove, a reinforcement grid, a tractor, a tank, or a ship. Don't forget to remove any paint or enamel.
Search for material for headphone
It is almost impossible to make a headset yourself. Therefore, we will look for a ready-made headset for our radio. There is no point in looking for headphones among household trash. In everyday life, low-impedance headphones are used, which are not suitable for our design. Thus, miniature headphones are not suitable for players and pocket receivers. Their internal resistance is only from 16 to 32 ohms. Higher-quality headphones from home audio systems are also not suitable - these are the same speakers, with an internal resistance of 8 ohms, respectively, and ordinary speakers are also not suitable due to their low resistance. And so, no matter how good your radio is, you won’t hear anything with all these headphones and speakers that I listed. Look for what we need. Pay attention to the handsets of city payphones, home phones, and intercoms. On the headphone body itself, the manufacturer usually indicates the value of the internal resistance; for us, the higher it is, the better, 1000 Ohms and higher. If nothing is indicated on the case, then take it with you anyway, in case it fits and works.
Fig.6. High-impedance headphone TON-2 with a resistance of 1600 Ohms. Back view
There is absolutely no point in connecting headphones in series to sum up the resistances. But how can we understand whether the earphone is suitable for us or not, if there is no one on the air anyway? What if it itself is faulty? Very simple. When you connect the antenna or ground to the receiver, you will hear a fairly loud click. This clicking sound occurs due to accumulated static voltage in the antenna circuit. The higher the impedance of the earphone, the louder the click will be. Do not try to hear the usual 50 Hz hum, which is usually induced by electrical wiring lines - there is no live electrical wiring around you!
Manufacturing
Self-made Detector (VD1)
So, we already have everything we need for assembly - a razor blade, a simple (graphite) pencil and a pin. The basis of the design is the point of contact between the blade and the lead of a simple pencil, which forms a semiconductor junction. For structural rigidity, the blade must be secured to a small wooden plank using a nail. First you need to think about how the mounting conductor will be attached to this blade. I recommend securing the blade and guide to the board with the same nail. We make the second half of the detector from a pin, a small piece of a simple pencil and a nail. The pencil needs to be sharpened. The hardness of the stylus does not matter at the initial stage. If you have a choice of pencils, you can try different options. The length of the pencil should not be long - only 2 - 5 centimeters. The pencil must be placed on the pin so that the needle enters the pencil between the graphite rod and the pencil shell, and reliable contact is ensured. The free end of the pin must also be attached to the board with a nail. The main thing is not to forget about the mounting wire - we attach it to the pin in the same way as to the blade. The assembled structure looks something like Figure 7. The most important thing here is to find the point of greatest sensitivity by moving the point of a pencil along the surface of the blade, adjusting the force of the pin as much as possible. I recommend finding some samples of blades and pencils and making some detectors. Both new and rusty canvases, in general, any kind, will be used. After all, the costs in our case will be completely justified.
Fig.7. Assembled detector
Oscillation coil
It is best to make the oscillating circuit coil for the medium-wave and long-wave ranges we have chosen without any core. I recommend using a rigid frame, for example, a piece of polyvinyl chloride (PVC) pipe with a diameter of 5 centimeters. Of course, a designer can also use cardboard, but cardboard tends to get damp. You will need a wire with a diameter of no more than 1 mm; it will be better if you find a wire with a diameter of about 0.3 mm. You will be very lucky if you find a network cable used to connect computers to a network. It can be found in sufficient quantities in office premises under the ceiling, hidden behind the cladding.
It contains exactly 8 conductors of the required diameter. Imagine, a network cable 10 meters long will give you as much as 80 meters of much-needed installation wire to construct, which will work for almost any device, including a coil! And so, in the pipe (i.e. frame) we make two holes through which we pass the winding wire. The holes are necessary for fastening the wire, but you can try securing the wire with tape if you have it. The total number of turns that will need to be carefully laid turn to turn without overlap will be at least 100. The more the better, the greater the range you can cover. After every 20 turns, I recommend making loops - taps to which we will connect either an antenna, a detector, or capacitors in search of a signal. After final winding, the loops of the taps must be freed from insulation. Using the simple formula L = 2пR we can determine the total length of the wire for our coil is 15.7 cm - one turn, then for 100 turns 15.7 meters of wire will be required, for 200 turns at least 32 meters (including bends).
It will be very good if you find at least 4 meters of network cable (Fig. 8). I recently found 13 meters of network cable - that's 104 meters! The total winding length will be approximately the diameter of the conductor with insulation * the number of turns, somewhere around 1.1*100=110 mm for 100 turns or 1.1*200=220 mm for 200 turns. Keep this in mind when cutting the pipe.
Fig.8. Network cable for winding the oscillating circuit coil and mounting the circuit
So, the coil (Fig. 9) is almost ready, all that remains is to strip the insulation from the taps that we made (I recommended doing them after every 20 turns). You can do this by slightly scorching the conclusions and cleaning them, but the main thing here is not to overdo it and not ruin all your work. For the reliability of the design, it is best to fasten the branches - tie them tightly to the body with threads, but you don’t have to fasten them, in which case you should handle the coil more carefully.
The coil itself can be fixed on a board, or you don’t have to. Its location on the board does not affect the operation of our receiver.
Fig.9. Coil
Insulator
Everything from the antenna to the grounding is important in this receiver! The antenna mount must be of high quality in terms of radio functionality. The antenna must be mounted on insulators. Moisture, dampness, and snow have a great influence on the properties of the antenna, so you need to try to minimize these effects - that's what insulators are for. Naturally, they must be made of high-quality insulating materials. Wood is not suitable for these purposes, as it gets wet quickly.
The simplest and most affordable way to make insulators from the necks of glass or plastic bottles. A better insulator will be obtained from an entire plastic bottle (Fig. 2) if it is made in this way.
For a reliable homemade antenna insulator, I recommend using a regular plastic bottle. It makes an excellent insulator. To do this, two holes must be made in the neck and at the very base of the bottle. The neck and base of the bottle, as a rule, have greater wall thickness. In these holes it will be necessary to pass the antenna wire on one side and on the other side a wire or rope, with which this antenna will be attached to the mast (pole, tree, any tall object). You can throw one end of the rope using a weight onto a tree, and then pull the antenna itself up. Such an insulator will reliably hold a sufficiently long antenna, and this is important, because a long and thick wire will experience a noticeable load when tensioned.
Capacitors (Sn, Sbl)
Capacitors, as well as coils, can be made on your own. The easiest way to make a capacitor of constant capacity. For homemade capacitors with a capacity of up to several hundred picofarads, aluminum or tin foil, thin writing or tissue paper, and packaging polyethylene are used. You can find significant reserves of foil in the ruins of houses from gas or electric ovens. Foil can also be taken from damaged high-capacity paper capacitors, or you can use aluminum foil, which is used to wrap chocolate and some types of candies. For damaged capacitors, you can also use oiled paper as a dielectric. Look at the general diagram of the capacitor structure (Fig. 10b), and the manufacturing process (Fig. 10a) will be discussed in the second part.
Fig. 10. Making a capacitor
We will use capacitors in the oscillatory circuit circuit. It is best to make several capacitors, 7 of them. I propose to make the smallest capacitance with a nominal value of 100 picofarads and so on up to 700 picofarads. We will connect them one by one to the coil, thereby adjusting the range. Another capacitor is a blocking capacitor. It is connected in parallel to the headphone, its capacity is about 3000 picofarads.
Antenna
Antenna is the best amplifier! This is what folk wisdom says. The antenna must be of a certain length. Since we will listen to the long-awaited radio signals in the medium wave range, the antenna length will be determined as follows:
The frequency range of the expected signal is from 0.5 Megahertz to 2 Megahertz;
Accordingly, the wavelength will be in the range from 300/0.5 to 300/2 meters, i.e. from 600 meters to 150 meters;
The recommended antenna length is a quarter of the wavelength, i.e. from 150 meters to 37.5 meters.
This means that it will be necessary to construct an antenna fabric from at least pieces of wire, but with a total length of 37 to 150 meters. I recommend taking an average value of about 90 meters. But no shorter than 37 meters, because the antenna will not work well, and this is noticeable, believe me. No cables or leads from the antenna to the receiver are required; we will connect the antenna directly to the receiver - this will simplify the design. The second end of the antenna must be attached to the insulator, which I have already described, and suspended as high as possible. Higher! It’s better if it’s not just a tall tree, but a tall building or a tall power line support. Do not attach the antenna to unfamiliar wires! Suddenly there is still tension in them, then you are risking your life.
Fig. 11. Antenna Dipole
Grounding
Grounding is the other half of the antenna, which means it is also very important. It's best if you find a metal pipe sticking out of the ground. As an option, a heating metal battery or a water supply system pipeline or fittings are suitable. The main thing is that this structure has reliable contact with the ground anywhere, and the larger the contact area with the ground, the better. You can build your own grounding. In this case, the ground should be sufficiently moist. It is necessary to dig a hole deeper, pour water into it, throw an iron bed or bucket or any massive and voluminous metal object into the hole, after attaching a wire of sufficient length to it so that it can be connected to the receiver. Then fill the hole and water it to be safe (so that a bucket or bed can grow). If there is no water, then I recommend trampling the ground thoroughly.
Fig. 12. Slant beam antenna
So, our receiver is ready, the antenna is fixed to the tree, the grounding is dug into the ground, and we can start listening to the air.
Fig. 13. Ready detector receiver
Electrics, alternative energy, electrical equipment, DIY radio
We will talk about how to make the simplest and cheapest radio transmitter that anyone who doesn’t even understand anything about electronics can assemble.
Reception of such a radio transmitter occurs on a regular radio receiver (on a landline or in a mobile phone), at a frequency of 90-100 MHz. In our case, it will work as a radio extender for headphones from a TV. The radio transmitter is connected via an audio plug to the TV via a headphone jack.
It can be used for different purposes, for example:
1) wireless headphone extender
2) Radio nanny
3) A bug for eavesdropping and so on.
To make it we will need:
1) Soldering iron
2) Wires
3) Audio plug 3.5 mm
4) Batteries
5) Copper varnished wire
6) Glue (Moment or epoxy) but it may not be needed
7) Old boards from a radio or TV (if any)
8) A piece of simple textolite or thick cardboard
Here is his circuit, it is powered by 3-9 volts
The ends of the coil must be cleaned of varnish.
The entire structure of a homemade receiver is placed on a printed circuit board, except for variable resistors, an antenna, a speaker and a power supply. The box from under the head of a JRC car tape recorder was used as a body, since it is a little longer than its analogues in length - about a centimeter and a little deeper, which is what we need. PCB drawing in format here.
The FM receiver accepts the entire range from 88 to 108 MHz. I managed to tune it to seven radio stations, which are switched by smooth rotation of the variable resistor “TUNING”, but of the seven radio stations only five are of good quality, which is nevertheless very good for such a simple circuit, especially considering that the station is located at a distance more than 80 kilometers.
The receiver is very loud, and especially high-quality sound is obtained when connecting large external speakers. If you are not satisfied with the amplifier circuit, then the ULF chip can be replaced with any other one or removed altogether if you listen to the radio through headphones. The antenna is a piece of meter-long wire, but it is better to add a small antenna amplifier to the circuit, called a UHF (high frequency amplifier).
The resistance of the “VOLUME” resistor does not have to be 33 kΩ, any value within 10-47 kΩ can be used. Coils: coil L1 - frameless, 8 turns, wound on a frame with 3mm PEL wire 0.55mm. This is what sets up the FM receiver. L2 is the input circuit, wound with the same wire, to the same diameter, only it has 13 turns.
When setting up the receiver, you need to stretch or compress the L1 coil until you catch the entire FM range. But don't rush to stretch it. First try to catch stations with a fully compressed coil, as in my case. For example, I didn’t have to configure it at all.
The FM radio can be powered by an ordinary Chinese landline telephone power supply or another similar one, with a current of 0.05A (in the version without ULF) or 1A (with the TDA2003 chip). The KT315 transistor can be replaced with any similar one. When assembling the circuit without errors, the receiver starts working immediately.
Greetings! In this review I want to talk about a miniature receiver module operating in the VHF (FM) range at a frequency from 64 to 108 MHz. I came across a picture of this module on one of the specialized Internet resources, and I became curious to study it and test it.
I have a special awe for radios; I have loved collecting them since school. There were diagrams from the magazine “Radio”, and there were just construction kits. Every time I wanted to build a better and smaller receiver. The last thing I assembled was a design on the K174XA34 microcircuit. Then it seemed very “cool”, when in the mid-90s I first saw a working circuit in a radio store, I was impressed)) However, progress is moving forward, and today you can buy the hero of our review for “three kopecks”. Let's take a closer look at it.
View from above. 
View from below. 
For scale next to the coin. 
The module itself is built on the AR1310 chip. I couldn’t find an exact datasheet for it, apparently it was made in China and its exact functional structure is not known. On the Internet you can only find wiring diagrams. A Google search reveals: "This is a highly integrated, single-chip, stereo FM radio receiver. The AR1310 supports the FM frequency range of 64-108 MHz, the chip includes all FM radio functions: low noise amplifier, mixer, oscillator and low-dropout stabilizer. Requires a minimum of external components. Has good audio signal quality and excellent reception quality. AR1310 does not require control microcontrollers and no additional software except 5 buttons. Operating voltage 2.2 V to 3.6 V. consumption 15 mA, in sleep mode 16 uA ".
Description and technical characteristics of AR1310
- Reception of FM frequencies range 64 -108 MHz
- Low power consumption 15 mA, in sleep mode 16 uA
- Supports four tuning ranges
- Using an inexpensive 32.768KHz quartz resonator.
- Built-in two-way auto search function
- Support electronic volume control
- Supports stereo or mono mode (when contacts 4 and 5 are closed, stereo mode is disabled)
- Built-in 32 Ohm Class AB headphone amplifier
- Does not require control microcontrollers
- Operating voltage 2.2V to 3.6V
- In SOP16 housing
Pinout and overall dimensions of the module. 
AR1310 microcircuit pinout. 
Connection diagram taken from the Internet. 
So I made a diagram for connecting the module. 
As you can see, the principle couldn’t be simpler. You will need: 5 tact buttons, a headphone jack and two 100K resistors. Capacitor C1 can be set to 100 nF, or 10 μF, or not at all. Capacitances C2 and C3 from 10 to 470 µF. As an antenna - a piece of wire (I took a MGTF 10 cm long, since the transmitting tower is in my neighboring yard). Ideally, you can calculate the length of the wire, for example at 100 MHz, by taking a quarter wave or one eighth. For one eighth it will be 37 cm.
I would like to make a remark regarding the diagram. AR1310 can operate in different bands (apparently for faster station search). This is selected by a combination of pins 14 and 15 of the microcircuit, connecting them to ground or power. In our case, both legs sit on VCC.
Let's start assembling. The first thing I encountered was the non-standard pin-to-pin pitch of the module. It is 2 mm, and it will not be possible to fit it into a standard breadboard. But it doesn’t matter, I took pieces of wire and just soldered them in the form of legs. 
Looks good)) Instead of a breadboard, I decided to use a piece of PCB, assembling a regular “fly board”. In the end, this is the board we got. The dimensions can be significantly reduced by using the same LUT and smaller components. But I didn’t find any other parts, especially since this is a test bench for running. 
After applying power, press the power button. The radio receiver worked immediately, without any debugging. I liked the fact that the search for stations works almost instantly (especially if there are many of them in the range). The transition from one station to another takes about 1 s. The volume level is very high, it is unpleasant to listen to at maximum. After turning off the button (sleep mode), it remembers the last station (if you do not completely turn off the power).
Sound quality testing (by ear) was carried out using Creative (32 Ohm) drop-type headphones and Philips vacuum-type headphones (17.5 Ohm). I liked the sound quality in both. There is no squeakiness, a sufficient amount of low frequencies. I'm not much of an audiophile, but I was pleasantly pleased with the sound of the amplifier of this microcircuit. I couldn’t turn up the maximum volume in the Philips, the sound pressure level was painful.
I also measured the current consumption in sleep mode 16 μA and in working mode 16.9 mA (without connecting headphones). 
When connecting a load of 32 Ohms, the current was 65.2 mA, and with a load of 17.5 Ohms - 97.3 mA. 
In conclusion, I will say that this radio receiver module is quite suitable for domestic use. Even a schoolchild can assemble a ready-made radio. Among the “cons” (more likely not even cons, but features) I would like to note the non-standard pin spacing of the board and the lack of a display to display information.
I measured the current consumption (at a voltage of 3.3 V), as we see, the result is obvious. With a load of 32 Ohms - 17.6 mA, with 17.5 Ohms - 18.6 mA. This is a completely different matter!!! The current varied slightly depending on the volume level (within 2 - 3 mA). I corrected the diagram in the review. 
