How a radio works. Radio tuning

Dear visitors!!!

If we compare obsolete and modern models of radio receivers, they certainly have their own differences both in design and in electrical circuits. But the basic principle radio signal reception- not changeable. For modern models of radios, only the design itself changes and minor changes are made to the electrical circuits.

As for tuning the radio to a wave, then receiving transmissions in the ranges for:

• long waves \LW\;
• medium waves \SV\,

- usually carried out on a magnetic antenna. In ranges:

- reception of the sound of the radio receiver is received on a telescopic \outdoor\ antenna.

Figure 1 shows appearance and graphic designation of receiving antennas:

telescopic;

magnetic \antenna DV and SV\.

Reception-on a magnetic antenna

Figure 2 shows a visual representation of the obstruction by radio waves of obstacles \ for mountainous terrain \. The radio shadow area is represented as a zone inaccessible to radio waves by the receiver.

What is a magnetic antenna? - The magnetic antenna consists of a ferrite rod, and the coils of the magnetic antenna are wound on separate \insulated\ frames. The ferrite rod of a magnetic antenna for different radio receivers has its own diameter and length. The winding data of the coils, respectively, also have their own specific number of turns and their own inductance - for each of these circuits of the magnetic antenna.

As you understand, such concepts in radio engineering as each individual magnetic antenna circuit and magnetic antenna coil, - have the same meanings, that is, you can formulate your proposal in one way or another.

In radio receivers, in its upper part, a magnetic antenna LW and SW is mounted. In the photograph, the magnetic antenna looks like an oblong, cylindrical rod \made of ferrite\.

If each coil \ circuit \ of a magnetic antenna has its own inductance, respectively, it is designed to receive individual radio wave bands. For example, according to the electrical circuit of the radio receiver, you observe that the magnetic antenna consists of five separate circuits \L1, L2, L3, L4, L5\, two of which are necessary for the received range:

• DW \L2\;
• SW \L4\.

Other circuits L1 L3 L5 - are communication coils, one of which, let's say L5 is connected to an external antenna. This explanation is not given specifically for each diagram, because the meanings of the symbols in the diagrams may change, but is given general concept about the magnetic antenna.

Reception-on a telescopic antenna

telescopic radio antenna

Depending on the radio circuitry, the telescopic \whip antenna\ can be connected both to the input circuits of the long and medium wave ranges through a resistor and a coupling coil, or to the input circuits of the short wave range - through an isolation capacitor. From the taps of the coils of the DV, SV or KV circuits - the signal voltage is applied to the input of the RF amplifier.

Winding data-antennas

The winding on the circuits is carried out with a single or double wire. Each circuit has its own inductance. The amount of inductance in a loop is measured in henries. To rewind a circuit yourself, you need to know the winding data for that circuit. That is, you need to know:

• number of turns of wire;
• wire section.

All the necessary technical data for outdated models of radio receivers could be found in reference books. At this time, there is no such literature for modern models of radio receivers.

For example, for receivers:

• Climber-405;
• Giala-404,

- the winding data of the coils coincided with each other. That is, let's say the communication coil \ and there are several of them - in the circuit \ with its designation, could be replaced from one receiver circuit to another circuit.

A circuit malfunction is more often associated with mechanical damage to the wire \ accidentally touched the wire with a screwdriver and more \. When repairing the circuit \ its rewind \, it is usually taken into account, the number of turns of the old wire is taken into account and then the same number of turns is performed with a new wire, where its cross section is also taken into account.

In this article, we partially got an idea about the reception of sound by a radio receiver. Follow the rubric, further will be even more interesting.

About ten ... twelve years ago, articles on the restructuring of imported receivers with the FM band (88 ... 108 MHz) to the VHF-1 range (65.8 ... 75.0 MHz) were often published in amateur radio magazines. At that time, broadcasting was carried out exclusively in the VHF-1 band.

Now the situation has changed dramatically. The ether in the range of 100 ... 108 MHz is filled almost everywhere. On sale there are many imported and domestic radio receivers with a VHF-2 range or with common ones (VHF-1 and VHF-2).

Since the VHF-1 range was actually "orphaned", a giant fleet of old radios and radio tape recorders remained "out of work". You can give them a second life by relatively simple modification of the VHF units of these receivers. In doing so, the following points should be noted. Modification of inexpensive portable receivers ("VEF", "Sport", "Sokol", "Ocean", etc.) should be minimal and provide reception of 3 ... 7 VHF-2 broadcasting stations in the region. For stationary devices of a higher class with an external VHF antenna, it is desirable to keep all its technical parameters (sensitivity, local oscillator stability, wide scale, etc.).

Usually, the VHF radio receiver unit contains an input circuit, 1-2 UHF cascades, a local oscillator, a mixer, and IF cascades. As a rule, these are 4 (less common 5) LC circuits. Having a basic (even better, mounting) diagram of a radio receiver, it is easy to determine all the necessary nodes (inductors, capacitances, etc.). The first circuit of the IF and all subsequent cascades do not need to be reworked.

It is clear that for the range of 100 ... 108 MHz, the capacitances and inductances of all LC circuits of the VHF-1 unit must be reduced. Theory and practice state that the capacitance of the circuit changes in proportion to the wavelength, and the number of turns of the inductor - the square root of this value.

When moving from the VHF-1 range to the VHF-2 range and with constant inductances (the number of turns of the inductors does not change) - this is an option for portable receivers for medium frequency ranges (69.0 MHz and 104.0 MHz) - we obtain the following relationship for containers:

With UKV-2 \u003d 0.44 * With VHF-1.

With this in mind, in practice the following ratio of capacities is more suitable:

With UKV-2 \u003d (0.3 ... 0.35) * With VHF-1.

In addition, in VHF units, it is possible to change the inductance of the loop coils within certain limits by rotating the tuning cores. Usually, the local oscillator of the VHF-2 block for the range of 100 ... 108 MHz should be tuned within 110 ... 119 MHz (with a margin) at IF = 10.7 MHz, and within 106 ... 115 MHz at IF = 6, 5 MHz, i.e. above the signal frequency. On the circuit diagram of the VHF-1 block, we mark those capacities that will be completely soldered from the circuit, as well as those capacities that will be replaced by others with a lower rating. Usually these are miniature disk ceramic capacitors.

Capacitors must be selected in advance, cleaned and tinned, shortening them to a minimum. If there is no device for accurately measuring capacitance, the table below will partially help to solve the problem, where the size and color of the capacitor will suggest the limits of the nominal capacitance.

Table 1

For clarity, you can compare the capacitance ratings in the "VEF-221" and "VEF-222" radio receivers, which are built according to the same circuits with the same inductors ("VEF-221" has a range of 87.5 ... 108 MHz, " VEF-222" - 65.8...74.0 MHz). These data are taken from the factory manual (Table 2). The capacitance ratings are given in it in picofarads.

table 2

Similar schemes of VHF units are used by the VEF-215 radio receiver and the VEF RMD-287S radio receiver, so the data in Table 2 are also suitable for reworking the VHF units of these devices.

Another example is a removable auto-receiver of the Ural-auto-2 type (input circuit, two UHF stages on GT322A transistors, a local oscillator on a microcircuit of the 224th series with the ZHA1 or XA1 index). In the input circuit in the capacitive divider C1-C2, we change C1 \u003d 22 pF by 5.1 ... 6.8 pF, C2 \u003d 33 pF - by 10 ... 12 pF. Capacitors C5, C7 and C14 of 33 pF each (series capacitances with KPI of the 1st, 2nd stages of UHF and local oscillator) are changed to 12 ... 13 pF. In the local oscillator circuit, the tuning core made of ferrite (0 2.88 mm) is changed to brass with a thread (diameter 3 mm). Another example is the tuner "Radiotechnika T-101-stereo" (VHF unit on transistors KT368A and KT339A, restructuring - varicaps KVS111A). Parallel capacitances SZ = 15 pF (input circuit), C14 = 15 pF (UHF), C18 = 9.1 pF (local oscillator) are dismantled. Serial capacitances C4 = 130 pF, C13 = 130 pF (input circuit and UHF) are changed to 43 ... 47 pF, and C15 = 82 pF (local oscillator) - to 27 ... 33 pF. To stretch the scale, we carefully unsolder the loop coil of the local oscillator and unwind 1.5 turns from the top of the coil, 1 turn from the bottom (the tap from 0.9 ... 1.2 turns as it was). Then carefully solder the coil into place.

It is convenient to divide the process of alteration of blocks of VHF receivers into several stages.

1. We provide access to the VHF unit both from the side of the parts and from the side of the printed conductors by removing the covers of the receiver and the VHF unit.
2. We determine the LC circuits of the input circuit, UHF, local oscillator, mixer, and the first circuit of the IF (the last alteration does not apply).
3. Carefully unsolder the containers to be replaced and dismantled.
4. We solder new containers prepared in advance (with cut and tinned leads) for each individual circuit of the VHF unit.
5. After making sure that there are no errors, and the circuit is not broken (there are no bad solderings, short circuits of printed tracks, etc.), we turn on the power of the receiver and try to hear at least one powerful (in this place) VHF station. At the same time, we rotate the receiver tuning knob and the local oscillator core. It is very useful to have an industrial receiver with a VHF-2 range nearby. This will help to immediately identify the desired station in the tuned receiver. Having heard at least barely the station, the tuning cores of the coils and the tuning capacitors of the input circuit, the UHF and the mixer achieve a loud reception of this station. At this stage, you can determine whether you need to change the cores from ferrite to brass and vice versa.
6. By rotating the core of the local oscillator coil, we set the required place for this station on the receiver scale (focusing on an industrial receiver with a VHF-2 range). Usually, the section of the scale of the tuned receiver, where the stations of the range 100 ... 108 MHz are located, occupies a very small part of the constructive scale of the receiver (about one third).
7. We carry out conjugation of the circuits of the input circuit, UHF and the local oscillator of the tuned VHF unit. In the area near 100 MHz, we achieve the highest volume of the stations by rotating the tuning cores of the input circuit, UHF and mixer, and in the area near 108 MHz - by rotating the rotors of the tuning capacitors of the same cascades (in this case, you need to monitor the position of the receiver tuning knobs - the maximum capacity of the KPI or varicaps at the beginning of the range and their minimum capacity at the end). We repeat this operation 2-3 times. In conclusion, it is necessary to reduce the capacitance in the AFC circuit by 2 ... 2.2 times (if its value exceeds 5 ... 6 pF). The last stage must be carried out in the assembled VHF unit through the holes in the covers to adjust the capacitances and inductances with a dielectric screwdriver.

These general rules for reworking VHF units should be followed for various schemes and designs of units. Briefly about receiving antennas. Obviously, directional antennas provide excellent reception quality, but they need to be rotated. The author uses a single square for the rebuilt tuner "T-101-stereo" (in parallel, two copper wires with a diameter of 1.8 mm with a distance between them = 15 mm and with a perimeter of slightly less than 3 m). The wave impedance of the square is about 110 ohms, so it is powered by a PRPPM cable - 2 x 1.2 (wave impedance is about 135 ohms). The height of the mast on the five-story building is approximately 9 m. The plane of the square is perpendicular to the line Chisinau - Bendery - Tiraspol - Odessa. As a result, more than 10 stations from Chisinau and 3-4 powerful stations from Odessa are heard.

Sources

1. A brief guide to the REA designer (edited by R.G. Varlamov). -M.: Sov. Radio, 1972, pp. 275,286.
2. V.T. Polyakov "Direct Conversion Transceivers". - M.: 1984, p.99.
3. P.M. Tereshchuk and others. Handbook of a radio amateur, part 1. Kyiv: Technique, 1971, S.Z0.
4. "VEF-221", "VEF-222". Manual.
5. Radiotechnika (T-101-stereo tuner). Manual.
6. A.N. Maltese, A.G. Podolsky. Broadcast reception in a car.- M.: Radio and communication, 1982, p.72.
7. V. Kolesnikov "Antenna for FM reception". - Radiomir, 2001, N11, p.9.

For a long time, radios topped the list of the most significant inventions of mankind. The first such devices have now been reconstructed and changed in a modern way, however, little has changed in their assembly scheme - the same antenna, the same grounding and an oscillatory circuit to filter out an unnecessary signal. Undoubtedly, the schemes have become much more complicated since the time of the creator of the radio, Popov. His followers developed transistors and microcircuits to reproduce a better and more energy-consuming signal.

Why is it better to start with simple schemes?

If you understand the simple one, then you can be sure that most of the path to success in the field of assembly and operation has already been mastered. In this article, we will analyze several schemes of such devices, the history of their occurrence and the main characteristics: frequency, range, etc.

History reference

May 7, 1895 is considered the birthday of the radio. On this day, the Russian scientist A. S. Popov demonstrated his apparatus at a meeting of the Russian Physical and Chemical Society.

In 1899, the first 45 km long radio communication line was built between and the city of Kotka. During the First World War, the receiver became widespread direct amplification and electronic lamps. During the hostilities, the presence of a radio turned out to be strategically necessary.

In 1918, simultaneously in France, Germany and the USA, scientists L. Levvy, L. Schottky and E. Armstrong developed the method of superheterodyne reception, but due to weak vacuum tubes, this principle was widely used only in the 1930s.

Transistor devices appeared and developed in the 50s and 60s. The first widely used four-transistor radio receiver, the Regency TR-1, was created by German physicist Herbert Matare with the support of industrialist Jacob Michael. It went on sale in the US in 1954. All old radios worked on transistors.

In the 70s, the study and implementation of integrated circuits began. Receivers are now evolving with a lot of node integration and digital signal processing.

Device characteristics

Both old radios and modern ones have certain characteristics:

1. Sensitivity - the ability to receive weak signals.
2. Dynamic range - measured in Hertz.
3. Noise immunity.
4. Selectivity (selectivity) - the ability to suppress extraneous signals.
5. Self-noise level.
6. Stability.

These characteristics do not change in new generations of receivers and determine their performance and ease of use.

The principle of operation of radio receivers

In the most general form, the radio receivers of the USSR worked according to the following scheme:

1. Due to fluctuations in the electromagnetic field, an alternating current appears in the antenna.
2. Fluctuations are filtered (selectivity) to separate information from noise, i.e., its important component is extracted from the signal.
3. The received signal is converted into sound (in the case of radio receivers).

According to a similar principle, an image appears on a TV, digital data is transmitted, radio-controlled equipment works (children's helicopters, cars).

The first receiver looked more like a glass tube with two electrodes and sawdust inside. The work was carried out according to the principle of the action of charges on metal powder. The receiver had a huge resistance by modern standards (up to 1000 ohms) due to the fact that the sawdust had poor contact with each other, and part of the charge slipped into the airspace, where it dissipated. Over time, these sawdust were replaced by an oscillatory circuit and transistors to store and transfer energy.

Depending on the individual circuit of the receiver, the signal in it can undergo additional filtering by amplitude and frequency, amplification, digitization for further software processing, etc. A simple radio receiver circuit provides for a single signal processing.

Terminology

An oscillating circuit in its simplest form is called a coil and a capacitor closed in a circuit. With the help of them, from all incoming signals, it is possible to select the desired one due to the natural frequency of oscillations of the circuit. Radio receivers of the USSR, as well as modern devices, are based on this segment. How does it all work?

As a rule, radio receivers are powered by batteries, the number of which varies from 1 to 9. For transistor devices, 7D-0.1 and Krona batteries with a voltage of up to 9 V are widely used. The more batteries a simple radio receiver circuit requires, the longer it will work .

According to the frequency of received signals, devices are divided into the following types:

1. Longwave (LW) - from 150 to 450 kHz (easily scattered in the ionosphere). Significant are ground waves, the intensity of which decreases with distance.
2. Medium wave (MW) - from 500 to 1500 kHz (easily scattered in the ionosphere during the day, but reflected at night). During daylight hours, the radius of action is determined by ground waves, at night - by reflected ones.
3. Shortwave (HF) - from 3 to 30 MHz (they do not land, they are exclusively reflected by the ionosphere, therefore there is a radio silence zone around the receiver). With a low transmitter power, short waves can propagate over long distances.
4. Ultrashortwave (VHF) - from 30 to 300 MHz (have a high penetrating ability, as a rule, are reflected by the ionosphere and easily go around obstacles).
5. - from 300 MHz to 3 GHz (used in cellular communications and Wi-Fi, operate within the line of sight, do not go around obstacles and propagate in a straight line).
6. Extreme high frequency (EHF) - from 3 to 30 GHz (used for satellite communications, reflected from obstacles and operate within line of sight).
7. Hyper-high frequency (HHF) - from 30 GHz to 300 GHz (they do not go around obstacles and are reflected like light, they are used extremely limitedly).

When using HF, MW and LW, broadcasting can be carried out while being far from the station. The VHF band receives signals more specifically, but if the station supports only it, then listening to other frequencies will not work. The receiver can be equipped with a player for listening to music, a projector for displaying on remote surfaces, a clock and an alarm clock. The description of the radio receiver circuit with such additions will become more complicated.

The introduction of microcircuits into radio receivers made it possible to significantly increase the receiving radius and frequency of signals. Their main advantage is relatively low energy consumption and small size, which is convenient for carrying. The microcircuit contains all the necessary parameters for signal downsampling and readability of the output data. Digital signal processing dominates modern devices. were intended only for transmitting an audio signal, only in recent decades the device of receivers has developed and become more complicated.

Schemes of the simplest receivers

The scheme of the simplest radio receiver for assembling a house was developed back in Soviet times. Then, as now, devices were divided into detector, direct amplification, direct conversion, superheterodyne type, reflex, regenerative and superregenerative. The simplest in perception and assembly are detector receivers, from which, it can be considered, the development of radio began at the beginning of the 20th century. The most difficult to build were devices based on microcircuits and several transistors. However, if you understand one scheme, others will no longer be a problem.

Simple detector receiver

The circuit of the simplest radio receiver contains two parts: a germanium diode (D8 and D9 are suitable) and a main telephone with high resistance (TON1 or TON2). Since there is no oscillatory circuit in the circuit, it will not be able to catch the signals of a certain radio station broadcast in a given area, but it will cope with its main task.

To work, you will need a good antenna that can be thrown on a tree, and a ground wire. To be sure, it is enough to attach it to a massive metal fragment (for example, to a bucket) and bury it a few centimeters into the ground.

Variant with oscillatory circuit

An inductor and a capacitor can be added to the previous circuit to introduce selectivity, creating an oscillatory circuit. Now, if desired, you can catch the signal of a specific radio station and even amplify it.

Tube regenerative shortwave receiver

Tube radios, the circuit of which is quite simple, are made to receive signals from amateur stations at short distances - in the ranges from VHF (ultra-short wave) to LW (long-wave). In this circuit, finger-type battery lamps work. They generate best on VHF. And the resistance of the anode load is removed by low frequency. All details are shown in the diagram, only coils and a choke can be considered homemade. If you want to receive television signals, then the L2 coil (EBF11) is made up of 7 turns with a diameter of 15 mm and a wire of 1.5 mm. Suitable for 5 turns.

Direct gain radio receiver with two transistors

The circuit also contains a two-stage bass amplifier - this is a tuned input oscillatory circuit of the radio receiver. The first stage is the RF modulated signal detector. The inductor is wound in 80 turns with a PEV-0.25 wire (from the sixth turn there is a tap from the bottom according to the scheme) on a ferrite rod with a diameter of 10 mm and a length of 40.

Such a simple radio receiver circuit is designed to recognize strong signals from nearby stations.

Super-generative device for FM bands

The FM receiver, assembled according to the model of E. Solodovnikov, is easy to assemble, but has a high sensitivity (up to 1 μV). Such devices are used for high-frequency signals (more than 1 MHz) with amplitude modulation. Due to strong positive feedback, the coefficient increases to infinity, and the circuit enters the generation mode. For this reason, self-excitation occurs. To avoid it and use the receiver as a high-frequency amplifier, set the coefficient level and, when it reaches this value, sharply reduce it to a minimum. A sawtooth pulse generator can be used to constantly monitor the gain, or it can be made simpler.

In practice, the amplifier itself often acts as a generator. With the help of filters (R6C7), which highlight low-frequency signals, the passage of ultrasonic vibrations to the input of the subsequent ULF cascade is limited. For FM signals 100-108 MHz, the L1 coil is converted into a half-turn with a cross section of 30 mm and a linear part of 20 mm with a wire diameter of 1 mm. And the L2 coil contains 2-3 turns with a diameter of 15 mm and a wire with a cross section of 0.7 mm inside the half-turn. Receiver amplification for signals from 87.5 MHz is possible.

Device on a chip

The HF radio, which was designed in the 1970s, is now considered the prototype of the Internet. Shortwave signals (3-30 MHz) travel great distances. It is easy to set up the receiver to listen to a broadcast in another country. For this, the prototype received the name of world radio.

Simple HF receiver

A simpler radio receiver circuit is devoid of a microcircuit. Covers the range from 4 to 13 MHz in frequency and up to 75 meters in length. Food - 9 V from the Krona battery. A wire can serve as an antenna. The receiver works on headphones from the player. The high-frequency treatise is built on transistors VT1 and VT2. Due to the capacitor C3, a positive reverse charge arises, regulated by the resistor R5.

Modern radios

Modern devices are very similar to the radio receivers of the USSR: they use the same antenna, on which weak electromagnetic oscillations occur. High-frequency vibrations from different radio stations appear in the antenna. They are not used directly for signal transmission, but carry out the work of the subsequent circuit. Now this effect is achieved with the help of semiconductor devices.

Receivers were widely developed in the middle of the 20th century and have been continuously improved since then, despite their replacement mobile phones, tablets and TVs.

The general arrangement of radio receivers has changed slightly since the time of Popov. We can say that the circuits have become much more complicated, microcircuits and transistors have been added, it has become possible to receive not only an audio signal, but also to embed a projector. So receivers evolved into televisions. Now, if you wish, you can build in the device whatever your heart desires.

With just one chip, you will need to build a simple and complete FM receiver that is capable of receiving radio stations in the 75-120 MHz range. The FM receiver contains a minimum of parts, and its setup, after assembly, is reduced to a minimum. It also has good sensitivity for receiving VHF FM radio stations.
All this thanks to the Philips TDA7000 chip, which can be bought without problems on our favorite Ali Express -.

Receiver Circuit

Here is the receiver schematic. Two more microcircuits are added to it, so that in the end we get a completely finished device. Let's start looking at the diagram from right to left. On the LM386 running chip, a low-frequency amplifier for a small dynamic head, which has already become a classic, is assembled. Here, I think, everything is clear. The variable resistor controls the volume of the receiver. Further, a stabilizer 7805 is added above, which converts and stabilizes the supply voltage up to 5 V. Which is needed to power the receiver's microcircuit. And finally, the receiver itself is assembled on the TDA7000. Both coils contain 4.5 turns of wire PEV-2 0.5 with a winding diameter of 5 mm. The second coil is wound on a frame with a ferrite trimmer. The receiver is tuned to the frequency with a variable resistor. The voltage from which it goes to the varicap, which in turn changes its capacitance.
If desired, varicap and electronic control can be abandoned. And the frequency can be tuned either with a tuning core or a variable capacitor.

FM receiver board

I drew the circuit board for the receiver in such a way as not to drill holes in it, but to solder everything from the top, as with SMD components.

Placement of elements on the board

Used the classic LUT technology for the production of the board.

I printed it out, warmed it up with an iron, etched it and washed off the toner.

Soldered all the elements.

Receiver setup

After turning it on, if everything is assembled correctly, you should hear a hiss in the dynamic head. This means that everything is working fine so far. The whole setting comes down to setting the contour and selecting a range for reception. I tune by rotating the core of the coil. As the reception range is configured, the channels in it can be searched for by a variable resistor.

Conclusion

The microcircuit has good sensitivity, and a large number of radio stations are caught on a half-meter piece of wire, instead of an antenna. The sound is clear, without distortion. Such a scheme can be applied in a simple radio station, instead of a receiver on a supergenerative detector.

Greetings! In this review, I want to talk about a miniature receiver module operating in the VHF (FM) range at a frequency of 64 to 108 MHz. On one of the specialized Internet resources, I came across a picture of this module, I became curious to study it and test it.

I have a special trepidation for radios, I like to collect them since school. There were schemes from the magazine "Radio", there were just designers. Every time I wanted to assemble the receiver better and smaller. The last thing I collected was the design on the K174XA34 chip. 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.

Bottom view.

For scale next to the coin.

The module itself is built on the AR1310 chip. I could not find an exact datasheet for it, apparently it was made in China and its exact functional structure is not known. On the Internet, only wiring diagrams come across. Google search reveals: "This is a highly integrated, single-chip, stereo FM radio receiver. AR1310 supports 64-108 MHz FM frequency range, the chip includes all FM radio functions: low-noise amplifier, mixer, oscillator and low-drop stabilizer. Requires a minimum of external components.It has good audio 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 specifications AR1310
- FM frequency reception range 64 -108 MHz
- Low power consumption 15 mA, sleep mode 16 uA
- Support for four tuning ranges
- Using an inexpensive 32.768KHz quartz resonator.
- Built-in two-way function automatic search
- Support for electronic volume control
- Support for stereo or mono mode (when closing 4 and 5 pins, the stereo mode is turned off)
- 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.

Pinout of the AR1310 chip.

Wiring diagram taken from the Internet.

So I made a wiring diagram for the module.

As you can see, the principle is nowhere simpler. You will need: 5 tact buttons, a headphone jack and two 100K resistors. Capacitor C1 can be set to 100 nF, you can set it to 10 microfarads, or you can not set it at all. Capacitances C2 and C3 from 10 to 470 uF. As an antenna - a piece of wire (I took the MGTF 10 cm long, because the transmitting tower is in my neighboring yard). Ideally, you can calculate the length of the wire, for example at 100 MHz, taking a quarter wave or one eighth. For one eighth it will be 37 cm.
I would like to comment on the diagram. AR1310 can work in different ranges (apparently, for a faster search for stations). 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 a non-standard inter-output step of the module. It is 2 mm, and you can’t put it in a standard breadboard. But it doesn't matter, taking pieces of wire, just soldered them in the form of legs.


Looks good)) Instead of a breadboard, I decided to use a piece of textolite, assembling the usual "fly". As a result, here is the board. Dimensions can be significantly reduced by using the same LUT and smaller components. But I didn’t find any other details, especially since this is a test bench for running in.

After applying power, press the power button. The radio receiver immediately earned, without any debugging. I liked the fact that the search for stations works almost instantly (especially if there are a lot of them in the range). The transition from one station to another is about 1 s. The volume level is very high, it is unpleasant to listen to the maximum. After turning off the button (sleep mode), remembers the last station (if you do not completely turn off the power).
Sound quality testing (by ear) was carried out with Creative (32 ohm) “drop” type headphones and Philips “vacuum” type headphones (17.5 ohm). And in those, and in others, I liked the sound quality. There is no squeakiness, a sufficient amount of low frequencies. A music lover from me is useless, but the sound of the amplifier of this microcircuit was pleasantly pleased. In Phillips, I could not unscrew the maximum volume, the sound pressure level was painful.
I also measured the current consumption in sleep mode 16 μA and in working 16.9 mA (without connecting headphones).

When connecting a load of 32 ohms, the current was 65.2 mA, 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 schoolboy can assemble a ready-made radio. Of the "minuses" (rather not even cons, but features), I note the non-standard pin-to-pin pitch of the board and the lack of a display for displaying information.

I measured the current consumption (at a voltage of 3.3 V), as we see, the result is obvious. At a load of 32 ohms - 17.6 mA, at 17.5 ohms - 18.6 mA. This is a completely different matter!!! The current changed slightly depending on the volume level (within 2 - 3 mA). I corrected the diagram in the review.

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