High frequency block setting. How a radio works. Radio tuning Manual radio tuning

Sometimes the most ordinary things lead to a stupor. Tuning the radio on individual car brands is done in different ways. In this article, we will analyze in detail how this mysterious process occurs in the Kia Rio.

RADIO CONTROL

FM/AM band selection

Press the FM-AM button to select the frequency band as follows: FM AM FM

Manual radio tuning

To manually tune into a radio station, press the or button for at least 2 seconds. Then press the or button to increase or decrease the radio frequency.

Automatic search for radio stations

By briefly pressing the or button, an automatic search will start in ascending or descending radio frequency.

The search will stop when the radio finds the next radio station in frequency. If no new stations are found after the band has been completely covered, the radio will stop at the frequency from which the search was started.

Station preset buttons

To select a preset radio station, briefly (no longer than 2 seconds) press the corresponding button.
If the button is pressed for more than 2 seconds, the currently received radio station will be stored in memory instead of the previously programmed radio station.
For the FM and AM bands, six radio stations can be programmed.

Tuning the radio using the list of radio stations

By successively pressing the button, the mode of the list of radio stations will change as follows. way: List mode (list of radio stations) Preset mode (pre-programmed radio stations) List mode (list of radio stations)

Selecting a radio station from the list

Select radio station list mode or preset station mode by pressing the button
Press the or button to select the next or previous radio station from the list of radio stations or from preset radio stations.
If the tuning mode for pre-programmed radio stations is on, then you can select one of the six radio stations whose frequencies are stored in the memory cells of the radio receiver. However, in the station list mode, up to 50 stations with sufficiently strong signals in the FM or AM frequency bands can be memorized.
If the button is pressed for more than 2 seconds when the list of radio stations is on, the radio finds and memorizes the operating frequencies of radio stations with the strongest signal broadcasting in the FM or AM band. It may take some time to update the list of radio stations.
If the currently received radio station is not an RDS radio station, the broadcast frequency is displayed instead of the radio station name.
The RDS radio data system allows you to simultaneously transmit additional information in encoded digital form along with the main FM radio signal. The RDS system supports various information and service functions, such as showing the name of the radio station on the display, receiving traffic and local news, and automatically searching for a radio station broadcasting a program of a certain genre.

Alternative Radio Frequency (AF)

The AF function for selecting alternative radio frequencies can work in any mode, except for receiving AM band stations.

To enable this mode, press the SETTING button, the setup menu will appear on the display. Select the audio setup menu and press the (down) button to enter AF mode, and then press the ENTER button to ON. Each time the AF function is selected, its status alternates between ON and OFF. When the AF function is activated, “AF” is displayed on the display.

Automatic radio tuning function

The radio receiver compares the power of radio signals at all alternative frequencies, and automatically selects and tunes to the broadcast frequency that provides the best radio reception conditions.

Search by Information Type Code (PI)

If, as a result of searching through the list of alternative frequencies AF, the radio does not find any acceptable station, then it automatically proceeds to search for a radio station by PI code. During a PI code search, the radio searches for all RDS radios with the same PI code. During the PI code search, the sound is temporarily muted and the display shows "SEARCHING". The PI code search stops as soon as the radio finds a suitable radio station. If, after checking the entire frequency range, no station could be found, then the search stops and the radio returns to the previously tuned frequency.

EON Enhanced Network Data Update (This function also works when the AF function is off)

Enhanced Network Reception EON allows you to automatically retune the frequencies of pre-programmed stations to the same radio network. In addition, it becomes possible to use additional service functions provided by the network, such as receiving traffic reports. If the radio is on the FM band and is tuned to an RDS station that is part of the extended EON network, the EON indicator will appear on the display.

PS function (station name display)

When the radio is tuned in to an RDS station (manually or semi-automatically), RDS radio data reception starts and the name of the received station is displayed.

Alarm Interrupt Function (ALARM INTERRUPTION-EBU SPEC FOR INFO)

If the radio receiver receives the alarm code PTY31, then the current mode of operation of the audio system is automatically interrupted, and the broadcast of the message begins, with the message "PTU31 ALARM" displayed on the display. The volume level will then be the same as when transmitting traffic announcements. After the warning message ends, the audio system will immediately return to its original mode.

Local radio reception mode (REG)

Some radio stations of local importance are combined into a regional network, since each of them covers only a small area due to the lack of the necessary number of repeaters. If the radio signal becomes too weak while driving, the RDS system will automatically switch the audio system to another local radio station with a stronger signal.

If you turn on the REG mode when the radio is on the FM band and tuned to a local radio station, the radio tuner will be saved and there will be no switching to other local radio stations.

To enable this mode, press the SETTING button, the setup menu will appear on the display. Select the audio setup menu and press the (down) button to move to REG mode, then press the ENTER button to ON. When the REG function is selected in succession, it alternately turns on (ON) and turns off (OFF). When the REG function is on, “REG” appears on the display.

Traffic announcement mode (TA)

This function can work in any mode, except for receiving AM-band stations.

To enable this mode, press the SETTING button, the setup menu will appear on the display. Select the audio setup menu and press the ‘ (down) button to enter the TA mode, and then press the ENTER button to turn ON. Each time the TA function is selected, its status alternates between ON and OFF. When the TA function is enabled, the display will show “TA”.

The TA mode is activated by pressing the TA button. After turning on this mode, the TA indicator lights up on the display. The TA mode works regardless of whether the AF mode is on or off.

Function to interrupt the current mode by a traffic announcement

If the TA function is on, if the radio detects a traffic announcement, the current radio station or CD playback is interrupted. The message “TA INTERRUPT INFO” (traffic announcement interruption) appears on the display, followed by the name of the radio station broadcasting the traffic announcement. The sound volume will be adjusted to the preset level.

After the end of the traffic announcement, the audio system returns to the previously selected signal source and the previously set volume level.

If the audio system is tuned to an EON station and another radio station that is also part of the EON network is broadcasting a traffic announcement, the radio will automatically switch to the EON station that is broadcasting the traffic announcement. When the traffic announcement ends, the audio system will return to the previous signal source.

The interruption of the original mode for the traffic announcement is canceled if the TA button is pressed while the traffic announcement is being broadcast. This returns the TA function to standby mode.

This function can work in any mode, except for receiving AM radio stations. The RTU mode is activated if the PTY ON state in the RTU program type selection menu is activated, or if the RTU button is pressed to the ON state. The PTY symbol appears on the display

PTY radio program type selection mode

In order to set the required type of RTU radio program, do the following.

Press the SETTING button.
Press the (down) button to move to RTU, then press the ENTER button.
Select the desired program type from the menu, then press the ENTER button to confirm the selection.
Set the RTU function to ON. With successive selections of the RTU function, it alternately turns on (ON) and turns off (OFF).

After setting, to return to the normal display mode, press the | press the CD or FM-AM button three times or once.

Search function for a specified PTY program type

The audio system enters the search mode for a given type of RTU program when you press the search button or

If during the search a station is found broadcasting a program of the selected type, the radio will stop at that station and the sound volume will be adjusted to the preset level for the RTU function. If you want to search for another station broadcasting programs of the same type, press the search button again.

The PTY standby mode can be turned on when the audio system is in any mode other than receiving AM radio stations.

Press the PTY button to turn off PTY standby. The PTY indicator on the display will turn off.

If the radio detects a program with the required PTY code broadcast by the tuned radio station or an EON radio station, an interrupt signal will sound and the name of the PTY radio station will be displayed. The name of the interrupting PTY station will appear on the display and the volume will be adjusted to the level set for the PTY function.

Pressing the TA button while in PTY interrupt mode will return the radio to the previous playback source. However, the PTY interrupt standby mode remains on.

If you press the FM-AM band selection button or the CD player button while in PTY interrupt mode, the audio system will switch to the corresponding source. However, the PTY interrupt standby mode remains on.

If the radio has been tuned to a station that is not broadcasting RDS/EON radio data, when the audio system is switched to CD mode, the radio will automatically re-tune to the RDS/EON radio station that is broadcasting this data.

After returning to radio mode, it continues to receive the preset radio station.

Automatic retuning of the radio receiver is carried out in the following cases:

If the AF function is on and the TA function is off, if there is no RDS radio data for 25 seconds. or more.
If, with the AF function turned off and the TA function turned on, the radio receiver for more than 25 seconds. is not receiving a signal from a station broadcasting an npoi traffic message frame.
If, with the AF and TA functions turned on, the radio receiver for more than 25 seconds. is not receiving a signal from an RDS station broadcasting a traffic program.

Volume control mode

To set the SPEED VOL function (Volume Compensation Level according to vehicle speed), and to adjust the volume level for the PTY/TA functions, do the following:

Press the SETTING button.
Press the (down) button to move to Audio, then press the ENTER button.
Press the (down) button to move to Speed Sensitive Volume or PTY/TA, then press the ENTER button.
Press the (left) or (right) button to adjust the volume.
Press the ENTER button to confirm your choice.

To return to the normal display, press the button twice or press any of the CD or FM/AM buttons once.

Note: If this function is active, the faster the vehicle speed, the higher the volume level.

Thus, the multimedia radio system is fraught with some secrets that can surprise with its applicability and simplification of the life of a car enthusiast.

Watch an interesting video on this topic:

1. DETERMINE HOW WE WILL REBUILD THE RECEIVER.

So, with reasonable care, we open the device. We look at what the frequency tuning knob is connected to. It can be a variometer (a metal thing a few centimeters long, usually there are two of them or one double, with longitudinal holes into which a pair of cores are pushed in or out.) This option was often used before. Until I write about it. () And it may be a plastic cube a few centimeters in size (2 ... 3). It contains several capacitors that change their capacitance at our whim. (There is also a varicap tuning method. At the same time, the tuning control is very similar to the volume control. I have not seen such an option).

2. LET'S FIND THE HETERODYNE COIL AND THE CAPACITORS CONNECTED TO IT.

So, you have KPE! We act further. We are looking for copper coils around it (yellow, brown spirals of several turns. Usually they are not even, but crumpled and tumbled awry. And that's right, they are tuned that way.). We can see one, two, three or more coils. Don't be scared. Everything is very simple. We turn on your device in disassembled form (do not forget to connect the antenna more authentically) and tune it to any radio station (better not to the loudest one). After that, we touch it with a metal screwdriver or just with a finger (contact is optional, just swipe something near the coil. The reaction of the receiver will be different. The signal may become louder or interference may appear, but the coil we are looking for will give the strongest effect. It will immediately slip in front of us several stations and the reception will be completely broken. So this is what a HETERODYNE coil is. The frequency of the local oscillator is determined by a circuit consisting of this very coil and capacitors connected in parallel to it. There are several of them - one of them is located in the KPI and controls the frequency tuning (we catch with it different stations), the second is also in the KPI cube, or rather on its surface. Two or four small screws on the back of the KPI (usually facing us) are two or four trimmer capacitors. One of them is used to adjust the local oscillator. Usually these capacitors consist of two plates that run into each other when the screw is rotated. the bottom plate is exactly above the bottom one, then capacity is maximum. Feel these screws with a screwdriver. Move them back and forth a few (as little as possible) degrees. You can mark their initial position with a marker to insure against trouble. Which one affects the setting? Found? We will need it in the near future.

3. ONCE AGAIN, LET'S DECIDE WHERE WE ARE RESTRUCTURING AND ACT.

What range is in your receiver and what is needed. Do we lower the frequency or increase it? To lower the frequency, it is enough to add 1 ... 2 turns to the heterodyne coil. As a rule, it contains 5 ... 10 turns. Take a piece of bare tinned wire (for example, a lead from some long-legged element) and put a small prosthesis. After such a build-up, the coil must be adjusted. We turn on the receiver and catch some station. No stations? Nonsense, let's take a longer antenna and turn the tuning. Here's something caught. What is it. You'll have to wait until they say or take another receiver and catch the same thing. See how this station is located. At the right end of the range. Need to move even lower? Easily. Let's move the turns of the coil tighter. Let's pick up that station again. Good now? It only catches badly (the antenna needs a long one). Right. Now let's find the antenna coil. She's around somewhere. Wires from KPE must be suitable for it. Let's try turning on the receiver to insert it into it or simply bring some kind of ferrite core to it (you can take the DM choke by removing the winding from it). Has the reception volume increased? Exactly, it's her. To reduce the frequency, it is necessary to increase the coil by 2 ... 3 turns. A piece of hard copper wire will do. You can simply replace the old coils with new ones containing 20% more turns. The turns of these coils should not lie tightly. By changing the stretch of the coil and bending it, we change the inductance. The denser the coil is wound and the more turns it has, the higher its inductance and below will be the operating range. Keep in mind that the actual inductance of the loop is higher than the inductance of a single coil, as it adds up to the inductance of the conductors that make up the loop.

For the best reception of the radio signal, it is necessary that the difference in the resonant frequencies of the heterodyne and antenna circuits be 10.7 MHz - this is the frequency of the intermediate frequency filter. This is called the correct pairing of the input and heterodyne circuits. How to provide it? Read on.

ADJUSTMENT (COUPLE) OF THE INPUT AND HETERODYNE CIRCUIT.

FIG.1. The high-frequency part of the VHF-FM radio receiver board. It can be clearly seen that the input circuit trimmer capacitor (CA-P) is set to the minimum capacitance position (unlike the heterodyne trimmer capacitor CG-P). The accuracy of setting the rotors of trimmer capacitors is 10 degrees.

The local oscillator (LG) coil has a large hole in the winding, which reduces its inductance. This gap appeared during the setup process.

Another coil is visible at the top of the photo. This is the input antenna circuit. It is broadband and does not rebuild. The telescopic antenna is connected precisely to this circuit (through a transition capacitor). The purpose of this circuit is to remove gross interference at frequencies much lower than the operating ones.

AND ONE MORE ACTION SINCE WE ARE ALREADY HERE.

Tune in to your favorite station, then shorten the antenna as low as possible when the interference starts and adjust the IF filter, which looks like a metal square with a purple circle (in the middle left of the photo). Fine tuning of this circuit is very important for clear and loud reception. The slot setting accuracy is 10 degrees.

Once upon a time, there was a Sony radio tape recorder, during the sale they said that it was Japanese, the price made me believe, in the future he himself assured everyone that she was from there. Its objective advantage is pure sound. True, there was a small nuance - the FM range scale was 88-108 MHz, but the store had a magician who, for a "small share", created a miracle - he filled the scale with many Russian-speaking radio stations. They exploited the radio tape recorder in full, but remembering how much was paid for it, they did not throw it or it at it. So it was not badly preserved, despite the very respectable age. That's just the broadcasting stations that she caught, at first diminished, and then did not remain at all.

On the Internet, about setting up sound-reproducing equipment, there is a sea of information, it is written correctly, in detail. This is happiness for students of radio engineering universities, you can easily use it instead of notes to prepare for exams, and this infa will not help the owner of an ill radio, it’s not for him to increase his intellect, but to repair the receiver. Or throw it away, no worries.

He opened the case, began to disassemble it into its component parts. Neither the power supply, which turned out to be super primitive, which is at the bottom left, nor the tape drive mechanism of the tape recorder, to the right of it, have no complaints. One gives out its 12 V “on the mountain”, and the second regularly pulls the magnetic tape.

But I wanted to understand the printed circuit board a little. To warm up, I checked all the electrolytic capacitors for the actual presence of capacitance and ESR. It's hard to believe, but everything turned out to be in perfect order. I soldered and disassembled the volume control - a variable resistor, for example, a revision. Once upon a time, he messed up a little and was, by means of a medical syringe with a needle, awarded a portion of engine oil. Does it need a supplement? And there was so much oil in it that even now in a frying pan - I blotted the excess, returned it to its place. I washed the board from the side of the printed conductors with formic alcohol specially purchased at the pharmacy (they didn’t give anything else), and then, so that there was no white coating from it, with hot water and shampoo. It turned out not bad, although it is perceived by ear, this method is wildly.

The wire contacts suitable for the speaker were soldered. And around the circumference of the speaker, he installed a rim - a flexible tube cut along the length from a medical dropper. This is so that the metal of the speaker does not rely on the plastic of the case - it will definitely not be worse for the sound characteristics.

And then, very opportunely, I remembered that the master who was modifying the radio tape recorder spoke about some kind of wire spirals. There were several of them on the board, and everything was in the region of a variable capacitor. I partially assembled the device, turned it on and, at the desired range, began to touch the copper wires wound with rings with a screwdriver. Two did not respond, but barely touched the third, characteristic changes in sound appeared in the dynamics. Found! Pictured below. I touched it well with tweezers, and it dangles. I soldered it, straightened it and wound it on a new one, on a mandrel of a suitable diameter. Soldered into place. FM band came to life. Then he completely grew bolder and let's move the turns with a screwdriver (increase and decrease the gap between them). In response to my actions, the location and number of stations on the scale began to change. But two tweezers turned out to be the most convenient for tuning. He stretched and squeezed them like an accordion, only gently. You can clearly see this action in the video.

Video

As a result, I chose a combination of stations that was suitable for me and optimal in terms of location on the scale. The only difficulty is to do everything slowly, otherwise, you know, you want to do everything faster. Good luck! Babay iz Barnaula shared the simplest option for a possible restoration repair - settings.

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 band. 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 necessary 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.

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 No. 1 shows the 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 of radio waves around 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 scheme, because the meanings of the symbols in the schemes may change, but a general concept of a magnetic antenna is given.

Reception-on a telescopic antenna

telescopic radio antenna

Depending on the radio circuit, 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 rewinding \, 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.