Installing a radio receiver. Instructions on how to set up a radio on a radio from various manufacturers. Radio station preset buttons

You can use a radio to pass the time on the road. Typically, drivers prefer to listen to music that is unobtrusive, so that it plays in the background and does not interfere with steering. An autoradio is most suitable for this, which first needs to be configured. But many people don’t know how to properly set up the radio on their car stereo.

Basically, setting up the radio consists of several simple steps. The broadcast range is selected and radio channels are searched and stored in the tuner’s memory. The search for radio stations occurs either automatically or manual mode. In the first case, radio channels are stored in descending order of broadcast quality.

Let's take a closer look at how to configure the radio on common car radios.

Pioneer

If you are wondering how to tune the radio to Pioneer radio, don't worry, setup is very easy. At automatic configuration Pioneer presses FUNC, followed by BSM. To start searching for radio channels, press the right or up button; after finishing, the music of the first radio station found will turn on.

For manual installation In BAND mode, press >>| for a long time. A search will be launched for any first station within this radius. After which the device will stop scanning and start playing the found station. Then you will need to save it; to do this, hold down the key for a long time. the required number. If you do not need the found station, you need to press the right key and hold it. Scanning will continue until a new station is found.

With this function, you can store up to 6 stations in the first bank. After this manipulation, press the BAND button and get into the second bank, it is shown on the display as F2. In the second bank, you can similarly store up to 6 stations in memory, and there is also a third bank. Most often there are three banks, but there are more. As a result, if you have three banks, you will have 18 stations active and saved. Now you know how to set up the radio on your Pioneer radio.

Sony

Setting up the radio in the Sony radio will also not be a problem. Searching for stations is usually carried out in two common ways: manually or automatically. Automatic memorization of radio stations:

1. Turn on the radio. Long press the Source button and wait until TUNER appears on the display.
2. The range is changed by pressing the Mode button. If you press the joystick, a menu of options will appear.
3. Rotate the joystick until the VTM option appears. Radio channels are assigned to numbered keys as standard.

To manually scan and save you need:

1. Turn on the radio and start searching for stations.
2. After it is found desired radio station, you need to press a number key from 1 to 6, after which the name “Mem” will appear. Note: when saving a radio station on a digital number that already has a radio station, the previous one is automatically erased.

Thus, you can set up a radio in a Sony radio in 5-10 minutes.

Supra

After pressing the MODE button, select the Radio function, then RADIO and the saved band with the broadcast frequency will be displayed on the screen. Pressing BND selects the desired broadcast band.

Press and hold the >>|| button.

Then click the button >>|| for selection desired station. If these keys are not pressed for up to ten seconds, everything will return to its original operating mode.

Setting in automatic mode and scanning of selected radio stations

Search for existing radio stations in memory:

Briefly press the AS/PS key to start searching for saved radio channels. Any station can be listened to for about a couple of seconds. To automatically save radio channels, hold down the AS/PS key. The receiver will tune in to six optimal stations, which are the most powerful in this broadcast range. This option can be used in any wavelength range. Once the automatic saving of stations is completed, the receiver will stop scanning them.

To tune into a specific radio station, press the >>|| button, this will scan and select radio channels with the best reception signal. By pressing the >>|| button, you can manually select the station you want. Hold down the key numbered 1 to 6 for about a couple of seconds to memorize the channel under the desired key.

J.V.S.

When tuning stations, it is possible to leave 30 FM radio channels and 15 AM channels in the tuner.

Installing stations manually:

1. Select a broadcast band by pressing the TUNER BAND key.
2. Click on button 4 to set the station.
3. Hold down the key with any selected number on the panel to memorize the station in the radio's memory. The selected number will start blinking, after which you will see the station stored under the selected number. For example: To tune to station number 14, press the +10 key, followed by the 4 key for about three seconds or more.
4. To store other radio stations in the device’s memory, you need to repeat steps one through three. And to change the settings of the entire station, you need to repeat the entire process from the beginning.

Tuning stations in automatic mode:

Stations will be given numbers by increasing the frequency range.

1. Select the range by pressing the TUNER BAND key.
2. Press and hold the AUTO PRESET button on the panel.
3. To set a different range, you need to go through steps one through two again.

To replace selected stations in automatic mode, you must use manual installation.

Kenwood

Kenwood radios offer three types of autoradio settings: automatic (AUTO), local (LO.S.) and manual.

1. Press SRC until “TUnE” appears.
2. Press FM or AM to select a band.

For automatic setup, click >>| or |.

When manual settings After all the above steps, ST will light up, indicating the found station.

Setting up a transistor receiver is, in principle, little different from setting up a tube receiver. After making sure that the low-frequency amplifier is corrected and the lamps or transistors of the receiver are operating in normal modes, proceed to adjusting the circuits. Tuning begins with the detector stage, then moves on to the IF amplifier, local oscillator and input circuits.

It is best to customize circuits using a generator high frequency. If it is not there, then you can tune by ear, using the received radio stations. In this case, you may only need an avometer of any type (TT-1, VK7-1) and another receiver, the intermediate frequency of which is equal to the intermediate frequency of the receiver being tuned, but sometimes they are tuned without any instruments. When setting up, the Avometer serves as an indicator of the output signal.

When setting up the IF amplifier circuits in a tube receiver, when an RF generator and a tube voltmeter are used for this purpose, the latter must not be connected to the lamp grid, since the input capacitance of the voltmeter is added to the capacitance of the grid circuit. When setting up circuits, a voltmeter should be connected to the anode of the next lamp. In this case, the circuit in the anode circuit of this lamp must be bypassed with a resistor with a resistance of about 500 - 1000 Ohms.

Having finished setting up the IF amplification path, proceed to setting up the local oscillator and RF amplifier. If the receiver has several bands, then the tuning begins with the KB band, and then proceeds to tuning.

Contours of the NE and LW ranges. Short-wave coils (and sometimes medium-wave), unlike long-wave coils, usually do not have cores; they are most often wound on cylindrical (and sometimes ribbed) frames. The inductance of such coils is changed when adjusting the circuits, moving or pushing apart the turns of the coils.

In order to determine whether the turns should be shifted or moved apart in a given circuit, it is necessary to alternately insert a piece of ferrite and a brass (or copper) rod into the coil or bring it closer to it. It is even more convenient to perform this operation if, instead of a separate piece of ferrite and a brass rod, you use a special combined indicator stick, at one end of which magnetite (ferrite) is fixed, and at the other - a brass rod.

The inductance of the RF amplifier circuit coil should be increased if, at the points where the circuits connect, the volume of the signal at the receiver output increases when ferrite is introduced into the coil and decreases when a brass rod is introduced, and vice versa, the inductance should be reduced if the volume increases when a brass rod is inserted and decreases with the introduction of ferrite. If the circuit is configured correctly, a weakening of the signal volume at the interface points occurs when both ferrite and brass rods are introduced.

The circuits of the NE and LW ranges are configured in the same order. Changing the inductance of the circuit coil at the coupling points is carried out in these ranges by appropriate adjustment of the ferrite core.

When making homemade contour coils, it is recommended to wind a few obviously extra turns. If, when setting up the circuits, it turns out that the inductance of the loop coil is insufficient, winding up the turns on the finished coil will be much more difficult than winding up the extra turns during the setup process itself.

To make it easier to adjust the contours and calibrate the scale, you can use the factory receiver. By comparing the angles of rotation of the axes of the variable capacitors of the tuned receiver and the factory one (if the blocks are the same) or the position of the scale indicators, determine in which direction the circuit adjustment needs to be shifted. If the station on the scale of the tuned receiver is closer to the beginning of the scale than that of the factory one, then the capacitance of the tuning capacitor of the local oscillator circuit should be reduced, and vice versa, if closer to the middle of the scale, it should be increased.

Methods for checking a local oscillator in a tube receiver. You can check whether the local oscillator is working in a tube receiver different ways: Using a voltmeter, optical tuning indicator, etc.

When using a voltmeter, it is connected in parallel with the resistor in the anode circuit of the local oscillator. If the short circuit of the capacitor plates in the local oscillator circuit causes an increase in the voltmeter readings, then the local oscillator is working. The voltmeter must have a resistance of at least 1000 Ohm/V and be set to a measurement limit of 100 - 150 V.

Checking the operation of the local oscillator with an optical tuning indicator (6E5C lamp) is also simple. To do this, the control grid of the local oscillator lamp is connected with a short conductor to the grid of the 6E5C lamp through a resistor with a resistance of 0.5 - 2 MOhm. Dark sector of the setting indicator when normal operation The local oscillator must be completely closed. By changing the dark sector of the 6E5C lamp when rotating the receiver tuning knob, one can judge the change in the amplitude of the generator voltage in different parts of the range. If the amplitude unevenness is observed within significant limits, more uniform generation over the range can be achieved by selecting the number of turns of the coupling coil.

The operation of the local oscillator of the transistor receiver is checked by measuring the voltage at the local oscillator load (most often at the emitter of the transistor of the frequency converter or mixer). The local oscillator voltage, at which frequency conversion is most effective, lies in the range of 80 - 150 mV on all ranges. The voltage across the load is measured with a lamp voltmeter (VZ-2A, VZ-3, etc.). When the local oscillator circuit is closed, its oscillations are interrupted, which can be noted by measuring the voltage across its load.

Sometimes self-excitation can be eliminated very in simple ways. So, in order to eliminate self-excitation in the IF amplification stage, a resistor with a resistance of 100 - 150 Ohms can be connected to the control grid circuit of the lamp of this stage. The amplification of the intermediate frequency voltage in the cascade will decrease slightly, since only a small part of the input signal voltage is lost across the resistance.

In transistor receivers, self-excitation can occur if the battery or batteries are discharged. In this case, the battery should be replaced and the batteries should be charged.

In some cases, self-excitation in the receiver and TV can be eliminated by such measures as moving the grounding individual elements diagrams, re-installation, etc. Evaluate effectiveness measures taken You can often combat self-excitation in the following way.

Rice. 25. To explain the method of eliminating self-excitation in transistor reflex receivers

The receiver or TV is connected to an adjustable power source (that is, to a source whose voltage supplied to the anode circuits can be varied within wide limits), and a lamp voltmeter or other pointer indicator. Since at the moment self-excitation occurs, the voltage at the output of the receiver changes sharply, the deviation of the indicator arrow makes it easy to note this. The voltage taken from the source is controlled by a voltmeter.

If self-excitation occurs when rated voltage, then the supply voltage is reduced to a value at which generation stops. Then they take certain measures against self-excitation and increase the voltage until generation occurs, noting it on a voltmeter. If the measures are successfully taken, the threshold for self-excitation should increase significantly.

In transistor reflex receivers, self-excitation can occur due to poor placement of the high-frequency transformer (or inductor) relative to the magnetic antenna. Such self-excitation can be eliminated by using a short-circuited turn of copper wire with a diameter of 0.6 - 1.0 mm (Fig. 25). A U-shaped wire bracket is threaded through the hole in the board, bent from the bottom, twisted and soldered to the common wire of the receiver. The bracket can serve as an element for fastening the transformer. If the transformer winding is wound uniformly on the ferrite ring, then the corresponding orientation of the short-circuited turn relative to other ferrite parts is not required.

Why does the receiver “howl” on the KB band. It can often be observed that a superheterodyne receiver, when receiving a broadcast station on short waves, begins to “howl” with a slight detuning. However, if the receiver is tuned more accurately to the station being received, reception becomes normal again.

The reason for the "howl" when the receiver operates on short waves is the acoustic coupling between the receiver's loudspeaker and the tuning capacitor bank.

This generation can be eliminated by improving the depreciation of the tuning unit, as well as reducing various accessible ways acoustic feedback- changing the method of mounting the loudspeaker, etc.

Setting up an IF amplifier using another receiver. At the beginning of this section, a method was described for tuning a radio receiver using simple instruments. In the absence of such devices, tuning radios is usually done by ear, without instruments. However, it should be said right away that this method does not provide sufficient adjustment accuracy and can only be used as a last resort.

To tune the IF amplifier circuits, instead of a standard signal generator, you can use another receiver, the intermediate frequency of which is equal to the intermediate frequency of the tuned receiver. -For a tuned tube receiver, the AGC wire running from the diode to the control grids of the adjustable lamps must be disconnected from the diode during setup and connected to the chassis. If this is not done, the AGC system will make it difficult to fine-tune the bandpass filters. In addition, when setting up an IF amplifier, it is necessary to disrupt the oscillations of the local oscillator by blocking its circuit with a capacitor with a capacity of 0.25 - 0.5 μF.

The auxiliary receiver used in this case does not need to be subjected to any significant modifications. To set up, you only need a few additional parts: a variable resistor (0.5 - 1 MOhm), two fixed capacitors and two or three fixed resistors.

Setting up amplifier circuits. The receiver IF is produced as follows. The auxiliary receiver is pre-tuned to one of the local stations operating in the long or medium wave range. Next, the common wires or chassis of both receivers are connected to each other, and the wire going in the tube receiver to the control grid of the lamp of the first IF amplification stage of the auxiliary receiver is disconnected and connected to the control grid of the lamp of the corresponding stage of the IF amplifier of the tuned receiver. In the case of setting up a transistor receiver, the IF signal through capacitors with a capacity of 500 - 1000 pF is supplied alternately to the bases of the transistors of the corresponding stages of the IF amplifier.

Then both receivers are turned on again, however, in order to avoid interference during tuning, the low-frequency part of the auxiliary receiver, as well as the local oscillator of the receiver being tuned, should be turned off (in tube receivers, by removing the lamps of the bass amplifier and local oscillator, respectively).

When setting up the IF amplifier stages of a transistor receiver, its local oscillator should be turned off by installing a jumper in the local oscillator circuit.

After this, by applying an intermediate frequency signal from the auxiliary receiver to the input of the IF amplifier being tuned and smoothly adjusting the settings of the IF circuits of the latter, we achieve audibility of the station to which the auxiliary receiver is tuned. Then they continue to adjust each circuit separately (to the maximum signal level), and the adjustment is best done using a pointer device connected to the output of the bass amplifier, or using an optical indicator (6E5C lamp or similar).

Start tuning from the last inverter circuit; the signal is supplied to the base of the corresponding transistor or directly to the grid of the lamp in the anode circuit of which the tuned circuit is included.

If the setting is carried out not according to the optical indicator, but according to the sound volume, then it is recommended to set the volume level to minimum, since the human ear is more sensitive to changes in the volume level with weak sounds.

About tuning the receiver by radio stations. Tuning a superheterodyne receiver - tube or transistor - for received stations without using an auxiliary receiver usually begins on the KB band. By adjusting the IF circuits for maximum noise and rotating the tuning knob, the receiver is set to any of the audible stations. If it is possible to receive such a station, then they immediately begin to adjust the IF circuits, achieving maximum audibility (tuning begins with the last IF circuit). Then the heterodyne and input circuits are tuned, first at short, then at medium and long waves. It should be noted that setting up receivers using this method is complex, time-consuming and requires experience and skills.

Lamp 6E5S - indicator during setup. As already mentioned, it is not recommended to adjust the receiver circuits in terms of sound volume, especially if you are installing high level output volume. The sensitivity of the human ear to changes in signal level during loud sounds is very low. Therefore, if you still have to tune the receiver by sound, then the volume control should be set to a low level, or, what is better, use an optical tuning indicator - a 6E5C lamp or another similar one.

By tuning superheterodyne receivers according to the received stations and using a 6E5C lamp as an indicator of tuning accuracy, it is more convenient to adjust the contours at an input signal level at which the dark sector of this lamp narrows to 1 - 2 mm.

To regulate the signal voltage at the receiver input, you can connect, for example, a variable resistance resistor in parallel with the antenna coil, the value of which, depending on the sensitivity of the receiver, can be selected in the range from 2 to 10 kOhm.

How to detect a faulty stage in an RF amplifier. When setting up or repairing a receiver, a cascade in which there is a malfunction can be detected using an antenna, alternately connecting it to the bases of transistors or to the grids of amplifier lamps and determining by ear by noise whether there are malfunctions in these cascades.

This method is convenient to use in cases where there are several RF amplification stages.

An antenna in the form of a piece of wire can also be used when testing the IF and RF amplification stages in televisions. Since shortwave stations often operate at frequencies close to the intermediate frequency of televisions, listening to these stations will indicate the serviceability of the audio channel,

WinAmp. It's very easy to listen to music files in mp3 format. But she still has one interesting feature- This is listening to radio stations. Of course, such functions will not surprise anyone; sometimes it is enough to go to the website of a popular radio station and listen to the Internet broadcast. But WinAmp offers users almost 9000 radio stations. And it doesn’t just offer, but sorts by style, direction, language and country.

How to set up a radio in WinAmp

To configure the radio correctly, you need to WinAmp player additionally install the WinAmp Library component. It is available for downloading from the Internet from the manufacturer's website. After downloading and installing the additional component, launch WinAmp. Let's start setting up the radio. Go to “Settings” and in the Online Media tab set the number of radio stations to listen to. By default, there are only 600 stations installed, but on the Internet their number is in the thousands. We set the value with a margin of 20 thousand. We exit the player and start searching for radio stations.

Select Internet Radio from the menu. Then in the window on the right we activate the Refresh button. The list of available radio stations will begin to download. From now on you can listen to radio stations.

To configure the radio correctly, you need to filter the list by style and direction. To do this, you can specify several types in the Genre menu - classical, rock, pop, jazz, etc., and you can also select countries. If the user’s list of priorities includes not only music, but also news, then you can activate filters by topic - politics, sports, regional news. In addition, there is a function to search for radio stations by name. Having selected the radio station you are interested in, activate playback either using the Play button or double-clicking the mouse. You can add your favorite radio stations to your “Favorites” list.

Using the WinAmp player, you can find many unexpected radio stations on the Internet. Foreign radio amateurs often broadcast “intercepted” police or air traffic control radio communications on the Internet. In a word, surveying radio broadcasts is just as entertaining as simply surfing the Internet. It will take several months of time and a substantial gigabyte of traffic to study radio stations.

Please note that WinAmp in radio mode consumes approximately 62 megabytes of Internet traffic per hour of listening. Radio stations transmit at 128 kbit/s, so owners of limited packages should take this fact into account.

The high-frequency block contains a converter stage, input and heterodyne circuits. In receivers of the first and highest classes, as well as in the VHF range, there is a high-frequency amplifier in front of the converter. Checking and adjusting the high-frequency unit can be divided into three stages: 1) checking local oscillator generation; 2) determining the boundaries of the range, often called range laying; 3) pairing of input and heterodyne circuits.

Laying ranges. The tuning of the receiver to the received station is determined by the tuning of the local oscillator circuits. Input and UHF circuits only increase the sensitivity and selectivity of the receiver. When tuning it to different stations, the local oscillator frequency must always differ from the received frequency by an amount equal to the intermediate one. To ensure constant sensitivity and selectivity over the range, it is desirable that this condition be met at all frequencies in the range. However, this is the frequency ratio over the entire range

is ideal. With one-handed setup, it is difficult to obtain such a pairing. Local oscillator circuits used in broadcast receivers provide precise matching of the settings of the input and local oscillator circuits in each band at only three points. In this case, the deviation from ideal conjugation at other points of the range turns out to be quite acceptable (Fig. 82).

For good sensitivity on the KB range, two precise pairing points are sufficient. The necessary relationships between the frequencies of the input and heterodyne circuits are achieved by complicating the circuit of the latter. The heterodyne circuit, in addition to the usual tuning capacitor C 1 and tuning capacitor C2, includes an additional capacitor SZ, called a mating capacitor (Fig. 83). This capacitor (usually a fixed capacitance with a tolerance of ±5%) is connected in series with a variable capacitor. The inductance of the local oscillator coil is less than the inductance of the input circuit coil.

To correctly determine the boundaries of the range, you must remember the following. The local oscillator frequency at the beginning of each range is mainly affected by a change in the capacitance of the tuning capacitor C 2, and at the end of the range - by a change in the position of the inductor core L and the capacitance of the mating capacitor SZ. The beginning of the range can be considered the maximum frequency to which the receiver can be tuned in a given range.

When starting to set up the local oscillator circuits, you should find out the sequence of settings by range. In some receiver circuits, the CB band loop coils are part of the DV band loop coils. In this case, you need to start tuning with medium wave and then tune to long wave.

Most receivers use a band switching scheme that allows each band to be adjusted independently. Therefore, the configuration sequence can be any.

The range is set using the two-point method, the essence of which is to set the limit of the highest frequency (beginning of the range) using a tuning capacitor, and then the lower frequency (end of the range) with the core of the loop coil (Fig. 84). But when setting the limit of the end of the range, the setting of the beginning of the range is somewhat lost. Therefore, you need to check and adjust the beginning of the range again. This operation is performed until both points in the range are in compliance with the scale.

Pairing of input and heterodyne circuits. The setting is made at two points and checked at the third. The exact coupling frequencies in receivers with an intermediate frequency of 465 kHz for the middle of the range (f av) and the ends (f 1 and f 2) can be determined by the formulas:

The circuits are paired at design points, which for standard broadcasting ranges have the following values

In individual radio models, the pairing frequencies may vary slightly. The lower precision coupling frequency is usually selected 5...10% higher than the minimum frequency of the range, and the upper frequency is 2...5% lower than the maximum. Capacitors with variable capacitance allow you to tune the circuits to exact matching frequencies when turning at angles of 20...30, 65...70 and 135...140°, measured from the position of the minimum capacitance.

To configure tube radio receivers and achieve pairing, the output signal of the generator is connected to the input of the radio receiver (Antenna, Ground sockets) through the all-wave equivalent of the antenna (Fig. 85). Transistor radios that have an internal magnetic antenna are tuned!: using a standard field generator, which is a loop antenna connected to the generator through a non-inductive resistor with a resistance of 80 Ohms.

The decade divider at the end of the generator cable is not connected. The antenna frame is made square with a side of 380 mm from copper wire with a diameter of 4...5 mm. The radio receiver is located at a distance of 1 m from the antenna, and the axis of the ferrite rod should be perpendicular to the plane of the frame (Fig. 86). The magnitude of the field strength in μV/m at a distance of 1 m from the frame is equal to the product of the readings of the generator's smooth and step attenuators.

In the KB band there is no internal magnetic antenna, so the signal from the generator output is fed to the socket external antenna through a capacitor with a capacity of 20...30 pF or to a whip antenna through a decoupling capacitor with a capacity of 6.8...10 pF.

The receiver is tuned on a scale to the highest precise coupling frequency, and the signal generator is adjusted to the maximum voltage at the receiver output. By adjusting the tuning capacitor (trimmer) of the input circuit and gradually reducing the generator voltage, we achieve a maximum increase in the output voltage of the receiver. Thus, pairing is carried out at this point in the range.

Then the receiver and generator are tuned to a lower precise coupling frequency. By rotating the core of the input circuit coil, the maximum voltage is achieved at the output of the receiver. For greater accuracy, this operation is repeated until the maximum voltage at the receiver output is reached. After adjusting the contours at the edges of the range, check the accuracy of the pairing at the middle frequency of the range (third point). To reduce the number of tunings of the generator and receiver, the operations of setting the range and pairing the circuits are often performed simultaneously.

Setting up the LW band. The standard signal generator remains connected to the receiver circuit through the equivalent of an antenna. The generator is set to a lower frequency range of 160 kHz and an output voltage of 200...500 µV with a modulation depth of 30...50%. The lower coupling frequency is set on the receiver scale (the rotation angle of the KPI rotor is approximately 160...170°).

The gain control is moved to the maximum gain position, and the band control is moved to the narrow band position. Then, by rotating the core of the heterodyne circuit coils, the maximum voltage is achieved at the output of the receiver. Without changing the frequencies of the generator and receiver, the coils of the UHF circuits (if any) and input circuits are adjusted in the same way until the maximum voltage is obtained at the output of the receiver. At the same time, the generator output voltage is gradually reduced.

Having adjusted the end of the DV range, set the variable capacitor to the position corresponding to the coupling point at the highest frequency of the range (KPI rotation angle 20...30°). The generator frequency is set to 400 kHz, and the output voltage to 200...600 µV. By rotating the trimming capacitors of the circuits, first the local oscillator, and then the UHF and input circuits, the maximum output voltage of the receiver is achieved.

Tuning the circuits at the highest frequency of the range changes the tuning at the lower frequency. To increase the accuracy of the settings, the described process must be repeated in the same sequence 2...3 times. When re-adjusting the rotor, the KPI should be placed in the previous position, i.e. in the one in which the first adjustment was carried out. Then you need to check the accuracy of the pairing in the middle of the range. The frequency of the exact pairing in the middle of the LW range is 280 kHz. By setting this frequency on the generator and receiver scale respectively, the calibration accuracy and sensitivity of the receiver are checked. If there is a dip in the sensitivity of the receiver in the middle of the range, then it is necessary to change the capacitance of the coupling capacitor and repeat the tuning process.

The final stage is checking that the settings are correct. To do this, a test stick, which is an insulating rod (or tube), is inserted into the tuned circuit first with one end and then with the other end, with a ferrite rod fixed at one end and a copper rod at the other. If the adjustment is made correctly, then when any end of the test stick is brought to the circuit coil field, the signal at the receiver output should decrease. Otherwise, one end of the stick will reduce the signal, and the other will increase it. After the LW band is configured, you can similarly configure the MW and HF bands. However, as already noted, on the HF band it is enough to pair at two points: at the lower and upper frequencies of the range. In most radio receivers, the KB range is divided into several subbands. In this case, the exact pairing frequencies have the following values!

Features of setting the HF range. When tuning the HF band, the signal from the generator can be heard in two places on the tuning scale. One signal is the main one, and the second is the so-called mirror signal. This is explained by the fact that on the HF band the mirror signal is suppressed much worse, and therefore it can be confused with the Main signal. Let us explain this with an example. A voltage with a frequency of 12,100 kHz is applied to the receiver input, i.e., the beginning of the HF range. In order to obtain a frequency equal to the intermediate frequency at the output of the frequency converter, i.e. 465 kHz, it is necessary to adjust the local oscillator to a frequency equal to 12,565 kHz. When the local oscillator is tuned to a frequency of 465 kHz below the received signal, i.e. 11,635 kHz, an intermediate frequency voltage is also provided at the output of the converter. Thus, the intermediate frequency in the receiver will be obtained at two frequencies, the local oscillator, one of which is higher than the signal frequency by the amount of the intermediate frequency (correct), and the other lower (incorrect). In percentage terms, the difference between the correct and incorrect local oscillator frequencies is very small.

Therefore, when setting the HF range, you should choose from two local oscillator settings the one that is obtained with a lower capacitance of the circuit capacitor or with a more inverted coil core. The correct setting of the local oscillator is checked at a constant frequency of the generator signal. When increasing the capacitance (or inductance) of the local oscillator circuit, the signal should be heard in one more place on the receiver scale. You can also check the correctness of the local oscillator settings while keeping the receiver settings unchanged. When the frequency of the generator signal changes to a frequency equal to two intermediate ones, i.e., 930 kHz, the signal must also be heard. The higher frequency in this case is called the mirror frequency, and the lower frequency signal is the main one.

Setting up the antenna filter. Setting up the high frequency unit begins with setting up the antenna filter. To do this, the output signal of the generator is connected to the input of the receiver through the equivalent of an antenna. On the frequency scale of the generator, a frequency of 465 kHz and a modulation depth of 30...50% are set. The output voltage of the generator must be such that the output meter connected to monitor the output voltage of the receiver shows a voltage of the order of 0.5... 1 V. Receiver range switch set to the DV position, and the tuning pointer to the frequency of 408 kHz. By rotating the core of the antenna filter circuit, achieve a minimum voltage at the receiver output, while increasing the output voltage of the generator as the signal weakens.

After completing the setup, all adjusted cores of the loop coils and the positions of the magnetic antenna coils must be fixed.

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, but little has changed in their assembly circuit - the same antenna, the same grounding and an oscillating circuit for filtering out unnecessary signals. Undoubtedly, circuits have become much more complicated since the time of the creator of radio, Popov. His followers developed transistors and microcircuits to reproduce a higher quality and energy-consuming signal.

Why is it better to start with simple circuits?

If you understand the simple one, 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 circuits of such devices, the history of their origin and the main characteristics: frequency, range, etc.

Historical reference

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

In 1899, the first radio communication line, 45 km long, was built between and the city of Kotka. During World War I, direct amplification receivers and vacuum tubes became widespread. During 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 superheterodyne reception method, but due to weak electron tubes wide use this principle was only received in the 1930s.

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

Study and implementation began in the 70s integrated circuits. Receivers are now being developed through greater integration of nodes and digital signal processing.

Device characteristics

Both old and modern radios have certain characteristics:

1. Sensitivity is 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, USSR radio receivers worked according to the following scheme:

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

Using a similar principle, an image appears on a TV, digital data is transmitted, and radio-controlled equipment (children’s helicopters, cars) operates.

The first receiver was 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 air space, where it was dissipated. Over time, these filings were replaced by an oscillating circuit and transistors to store and transmit energy.

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

Terminology

An oscillatory circuit in its simplest form is a coil and a capacitor closed in a circuit. With their help, you can select the one you need from all the incoming signals due to the circuit’s own frequency of oscillation. USSR radios, 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 type 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 .

Based on the frequency of received signals, devices are divided into the following types:

1. Long-wave (LW) - from 150 to 450 kHz (easily scattered in the ionosphere). What matters are ground waves, the intensity of which decreases with distance.
2. Medium wave (MV) - 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 grounded waves, at night - by reflected ones.
3. Shortwave (HF) - from 3 to 30 MHz (do not land, are exclusively reflected by the ionosphere, so there is a radio silence zone around the receiver). At low power transmitter, short waves can travel long distances.
4. Ultrashortwave (UHF) - from 30 to 300 MHz (have a high penetrating ability, are usually reflected by the ionosphere and easily bend around obstacles).
5. - from 300 MHz to 3 GHz (used in cellular communication and Wi-Fi, operate within visual range, do not go around obstacles and propagate in a straight line).
6. Extremely high frequency (EHF) - from 3 to 30 GHz (used for satellite communications, are reflected from obstacles and operate within line of sight).
7. Hyper-high frequency (HHF) - from 30 GHz to 300 GHz (they do not bend around obstacles and are reflected like light, they are used extremely limited).

When using HF, MF and DV radio broadcasting can be carried out while being far from the station. The VHF band receives signals more specifically, but if a station only supports it, then you won’t be able to listen on other frequencies. 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 reception radius and frequency of signals. Their main advantage is their relatively low energy consumption and small size, which is convenient for portability. The microcircuit contains all the necessary parameters for downsampling the signal and making the output data easier to read. Digital signal processing dominates modern devices. were intended only for transmitting an audio signal, only in recent decades the design of receivers has developed and become more complex.

Circuits of the simplest receivers

The circuit 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, reflex, regenerative and super-regenerative. Detector receivers are considered the simplest to understand and assemble, from which the development of radio can be considered to have begun at the beginning of the 20th century. The most difficult devices to build were those based on microcircuits and several transistors. However, once you understand one pattern, others will no longer pose a problem.

Simple detector receiver

The circuit of the simplest radio receiver contains two parts: a germanium diode (D8 and D9 are suitable) and main phone With high resistance(TONE1 or TONE2). Since there is no oscillatory circuit in the circuit, it will not be able to catch signals from a specific 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 onto a tree, and a ground wire. To be sure, it is enough to attach it to a massive piece of metal (for example, to a bucket) and bury it a few centimeters into the ground.

Option with oscillating circuit

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

Tube regenerative shortwave receiver

Tube radio receivers, the circuit of which is quite simple, are made to receive signals from amateur stations on short distances- for ranges from VHF (ultra-short wave) to LW (long wave). Finger battery lamps work on this circuit. 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 the coils and inductor 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 1.5 mm wire. 5 turns are suitable.

Direct amplification radio receiver with two transistors

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

This simple radio receiver circuit is designed to recognize powerful signals from nearby stations.

Supergenerative device for FM bands

The FM receiver, assembled according to E. Solodovnikov’s model, is easy to assemble, but has high sensitivity (up to 1 µV). Such devices are used for high-frequency signals (more than 1 MHz) with amplitude modulation. Thanks to strong positive feedback, the coefficient increases to infinity, and the circuit goes into 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. For continuous gain monitoring, you can use a sawtooth pulse generator, or you can do it simpler.

In practice, the amplifier itself often acts as a generator. Using filters (R6C7) that 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, coil L1 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 coil L2 contains 2-3 turns with a diameter of 15 mm and a wire with a cross-section of 0.7 mm inside a half-turn. Receiver amplification is possible for signals from 87.5 MHz.

Device on a chip

The HF radio receiver, whose circuit was developed in the 70s, is now considered the prototype of the Internet. Shortwave signals (3-30 MHz) travel great distances. It is not difficult to set up a receiver to listen to broadcasts in another country. For this, the prototype received the name world radio.

Simple HF receiver

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

Modern radios

Modern devices are very similar to radio receivers in the USSR: they use the same antenna, which produces weak electromagnetic oscillations. High-frequency oscillations appear in the antenna from different radio stations. They are not used directly to transmit a signal, but carry out the operation of the subsequent circuit. Now this effect is achieved using 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 design of radio receivers has changed slightly since Popov's time. We can say that the circuits have become much more complicated, microcircuits and transistors have been added, and it has become possible to receive not only an audio signal, but also to build in a projector. This is how receivers evolved into televisions. Now, if you wish, you can build whatever your heart desires into the device.