Sometimes, due to a low-quality radio receiver on a car radio, you have to buy separate HF amplifiers for normal radio reception. At the same time, the choice of such amplifiers is quite difficult, taking into account the fact that there are now a lot of cheap Chinese products on the market that do not really work.
One day they gave me such an amplifier for repair, or rather, so that I could assemble a normal amplifier in the same case.
I would like to present the design of a cheap FM amplifier for a radio receiver.
It turns out that this is not an amplifier at all, but God knows what. The circuit consists of only pairs of transistors, and one of them is simply for illuminating the LED.
Power is supplied from on-board network car 12 Volt and... nothing happens, only the LED indicator lights up and that’s it - no other reactions are observed from the car radio, with or without an amplifier - the reception is the same.
The photo shows the board of such an antenna amplifier, note - I did not repair anything, and did not touch the board at all, but mistakes are visible on the board - a large piece of solder, it is not clear why, an extremely dirty board, oxides everywhere, and generally a non-working, useless thing.
The price of such an amplifier is around 200 rubles, in exchange for pennies you can assemble antenna amplifier at home. A couple of working circuits of such amplifiers are presented below
These schemes are very similar to each other, there are very few differences. Both have been tested and are quite workable options, they are clearly more useful than a Chinese trinket, and they also do not contain scarce components.
The entire element base can be found in an old radio or tape recorder. Just one low-power transistor KT368, which can be replaced with any other RF transistor; among imported analogs, SS9018/C9018 is perfect - in theory the same thing.
And I also want to note one point, if you decide to buy a bicycle, for yourself or for your children, then I would like to recommend Pegasus. Excellent value for money, offered to you by the Ultrasport company.
Today, car antennas have different purposes. In times of combat, they receive communications, and in times of peace, they receive navigation information and broadcast channels. Due to the simplicity of the design, you can make a car antenna yourself. More on this later in the article.
This is a special device that receives electromagnetic radio signals and converts them into an electrical signal. To make an antenna for a car with your own hands, you need to decide on the type of modulation, wave range and purpose of the device. These are the three key components that go into the design.
Types of car antennas by purpose
Types of car antennas by installation method
Types of car antennas by mounting location and type of amplification
Based on the type of amplification, the following types of car antennas are distinguished:
At the mounting location:
Operating principle of a vehicle communication antenna
Size car antenna directly depends on the range. This is why 27 MHz communication antennas are so large. The most powerful variations can reach two meters in length, however, according to the rules of science, they should be even higher. To adjust the differences between the quarter wavelength and the actual size, there is an extension coil at the base.
On cars, the communication antenna is installed strictly vertically, which is determined by the type of polarization. It is worth noting that all communication antennas are capable of tilting using a lever in certain road conditions, for example, in order to overcome the span of a low bridge or not break in the forest. As a rule, communication antennas are used by owners of large trucks. Installation on jeeps and other cars is allowed, but the appearance will not be very attractive.
Digital car antenna, operating principle
Digital car antennas for TV reception, as a rule, look like police flashing lights, but are made in a different color scheme. There is nothing complicated in their design, they just have to accept a frequency of about hundreds of MHz. For example, the first multiplex in Moscow is located at a frequency of 559 MHz.
Digital car magnetic antennas are usually placed on the roof, and the wire runs directly above the door without any modifications. The signal is characterized by the presence of horizontal polarization; the main task of the device is to receive it from each azimuth.
Radio broadcast antenna
Radio broadcast antennas are both “flashing lights” and short rods, similar to those that receive walkie-talkie signals, but a little shorter.
Technical characteristics of frequencies of radio, television, navigation, radio communications
- Radio communication - SV (about 27 MHz).
- Navigation - GPS (about 400 MHz).
- Television - DVB–T (up to 900 MHz).
- Radio - FM or AM (about 70 - 108 MHz).
Also pay attention to the connector. As a rule, it matches most of the devices for which it is intended, but it would not be a bad idea to check this. There is an opinion that an external antenna receives better, but this only applies to reception in the city. On country roads, the glass of a regular passenger car is not capable of creating serious obstacles. However, interior car antennas are easier to install. It is worth noting that they are lower than external ones, which affects the quality.
You can find various hybrid models in the market. In addition, it is possible to switch reception from city to highway. Their difference is in the features of interference suppression and sensitivity, due to which the reception range outside the city is significantly increased. There are also unique tandems - a pair of similar-looking pins, the first of which is television broadcasting, and the second is radio or communications. Of course, to take full advantage of the kit, you need to have the appropriate receiving equipment available.
Tools, materials and devices to help the master
DIY car antenna, step-by-step instructions
It is worth saying that the car body is constantly in motion. That is why ordinary terrestrial household antennas will have dead reception zones in this case. When maneuvering, there will be quite long periods of time when there will be no reception. This refers to horizontal polarization. With vertical, it doesn’t matter where the signal comes from.
At self-production car antenna, a frame structure is used, which must be laid under the rear window seal of the car. It is slightly narrowed towards the top and has slightly different dimensions than required at a frequency of 27 MHz. That is why there is a capacitor in the center, which is used to tune the car antenna to the desired channel into resonance.
There are two receiving frequencies, for example:
- 28.2 and 68 MHz
- 27 and 65 MHz.
The upper resonance occurs for the lower radio broadcast range. Car antenna diagram:
- You should lay the MGTF wire 0.5 in a trapezoid along the perimeter of the rear window - sidewalls 22.5 + 22.5 and 45 cm, bottom edge 66.5 + 66.5 cm, top edge 56.5 + 56.5 cm.
- The pluses are where the wires for the corresponding capacitor will be added and the signal will be removed using the RK-50 cable.
- Two wires run vertically to the center, in the middle, of the glass, where a tuning capacitor is attached exactly in the center. The length of each is 45 centimeters. They need to be twisted in a zigzag and placed under an insulating tube.
- The cable must be soldered from the side, where the wire is cut off in the middle. There should be no gap on the opposite side.
How to install and connect an antenna
The car antenna is connected via the connector used by the communication equipment. Keep the cable length short.
Advantages of a DIY antenna
Such models are usually installed on the roof of a car and have a greater height than the passenger car itself. In the forest this is a definite plus. Moreover, there is no need to wind the matching device. In this case, ease of design, ease of installation and accessibility to any user are achieved.
In some cases, purchasing a car antenna and installing it is more expensive, more complicated and provides poorer reception quality. There is nothing complicated in the design below and every car enthusiast can try it out.
You will need
- - a piece of wire several meters long;
- - plug;
- - metal curtain clip;
- - soldering iron, solder and neutral flux;
- - OIRT-CCIR converter;
- - antenna amplifier or active antenna.
Instructions
In some cases, unstable reception in the VHF range is due to the low sensitivity of the receiver or radio. It should be noted that there is no dependence of this device parameter on its price. Try receiving the same station in the same room with several receivers - the one that provides the most reliable reception is the most sensitive of them.
You can indirectly determine the mediocre quality of the radio path of a receiver by the presence of an antenna socket, despite the fact that it has an antenna. If there is a socket, the manufacturer could have added it precisely in order to compensate for the low sensitivity.
The external antenna is a piece of wire several meters long. It should be completely unwound. To one end of the wire, solder either a plug, the type of which matches the type of socket on the receiver, or a metal curtain clip that fits onto the telescopic antenna. To ensure that such an antenna does not need to be equipped with lightning protection, do not make it outdoor under any circumstances.
Sometimes the following device helps improve the quality of reception in the FM range. Wind about 20 turns of insulated wire directly over the sheath of the coaxial cable going to yours. Connect one of its ends to the receiver in the manner indicated above.
Pocket players and mobile phones are used to receive FM radio stations or headsets. Replace this accessory with another one that has a longer wire, or extend it yourself if you know how to do it. The quality of reception and the number of received radio stations will increase significantly.
Often, even in the center, the receiver receives very few radio stations simply because it is designed for the VHF-1 range (65 - 74 MHz), while most stations today operate in the VHF-2 range (88 - 108 MHz). Changing a device from one band to another is a very painstaking operation, so you should only undertake it if you have the necessary experience for this. In the absence of such experience, a special attachment will help - the CCIR-OIRT converter. This device is available for sale on radio markets.
You can improve the quality of reception in the FM range of your car radio using an antenna amplifier or an active antenna. When choosing this device, you should remember that often, under the guise of such amplifiers, “dummies” are sold, in the housings of which there is nothing except a resistor and an LED. Therefore, they should be purchased only in company stores.
Some people like to use their car radio at home by connecting it to the power supply and speakers. There is a misconception that in this case it will work well without an antenna. But by attaching even a very short antenna to the radio, anyone can be convinced of the opposite.
Walkie-talkies are very popular among people who constantly need to keep in touch with each other. These are security guards, taxi drivers, truck drivers. Use mobile phone unprofitable due to high tariffs. But in such cases, it is necessary that the walkie-talkie be quite powerful so that you can talk without restrictions.
Instructions
If you need to increase the range of the radio, replace its helical antenna with a four-wave special rod, which can be purchased at any market. You can also use coaxial cable, which will significantly increase the signal. It is necessary to replace the antenna because manufacturers most often set the maximum range to be within a kilometer radius.
Next step– adjusting the frequency of the radio in the most optimal way so that it sends a signal over the longest distance.
FM ANTENNA AMPLIFIERS - HOW TO IMPROVE RADIO RECEPTION.
FOR WHAT: These devices are designed to improve VHF and FM radio reception. The amplifier must be connected to an outdoor passive antenna. This can be a standard antenna installed at the car manufacturer, or installed by the owner. Important! An antenna signal booster will not help if the antenna is broken.
Important! For proper operation and for high-quality reception, you need a passive antenna. The antenna plug is connected to the input jack of the car antenna amplifier, the amplifier plug is connected to the input jack of the radio. The amplifier is connected to the on-board vehicle +12 Volt network. It is important that the connection circuit of the amplifier for the car antenna is protected by a fuse; it is also important that when the car’s ignition is turned off, the device must turn off. The car antenna signal amplifier will work correctly in this case.
ADVANTAGES:
Passive antenna + antenna signal booster Triad is actually a powerful active antenna. Reception at distances of more than 50 km from the radio station will noticeably improve, wheezing and signal dropouts will disappear or become less noticeable. The use of cheap Chinese signal amplifiers usually only slightly improves the quality of reception. Triad products are designed and manufactured in Russia:
-powerful amplification components with high-quality range filters are used
-not only FM is amplified, but also VHF and AM
-allows you to turn off or adjust the gain
So, an amplifier for a car antenna is especially recommended for car enthusiasts:
- living at a distance of 50-120 km from an FM radio transmitter;
-a passive outdoor antenna is installed (mortise-mounted, magnetic, on the drain)
-if some stations are received with interference, spikes, etc.
YOU CAN BUY THE TRIAD 304 AMPLIFIER FROM RELIABLE AND PROVEN PARTNERS::
HIT SELLING amplifier Triad 304!
Approximate retail price 650 rubles
Effective operation of such devices is possible at distances from the radio station of 60-120 km, i.e. the potential buyer is a rural resident or a resident of nearby suburbs who wants to improve the quality of radio reception. If the car radio is received from strong noises, the signal disappears, not all radio stations are received - the use of an amplifier is justified. If the distance to the broadcast transmitter is more than 150 km, it is unlikely that anything, including an antenna amplifier, will help improve radio reception.
IMPORTANT! If your outdoor active antenna is damaged, it must be replaced. A situation often arises when, instead of replacing a broken active antenna, the consumer wants to improve reception using an amplifier. Will not help. The antenna will have to be changed, even if this is a labor-intensive task associated with the need to partially disassemble part of the body or trim of the car. If the antenna cannot be changed, you can install another - passive - antenna, connect the antenna signal amplifier to it, and disconnect the broken one from the radio.
The Triad-304 amplifier is recommended for use with an antenna and other passive built-in antennas.
It is not recommended for use with an active antenna due to the possibility of overexcitation of the radio input stage.
To ensure that the amplifier does not distort too strong a signal in the city, it is advisable to either turn it off or reduce the gain. This opportunity is provided to the consumer by Triad amplifiers - model 304 “Dalnoboi”. This product also enhances the AM ranges, i.e. long and medium waves. The use of amplifiers with an active antenna is not recommended; this will also lead to distortion and wheezing.
Car antenna amplifier VHF and FM. This is the simplest and cheapest amplifier - an improved analogue of Chinese amplifiers. When connected to a passive outdoor (external) antenna, the gain cannot be adjusted or turned off. Recommended in the most simple cases of poor reception.
car antenna amplifier VHF and FM radio with gain control. Convenient for consumers who periodically visit remote locations settlements.
car antenna amplifier for VHF and FM radio with gain switch off. Convenient for consumers who frequently and regularly visit remote locations.
powerful amplifier AM, VHF, FM auto antennas with gain switch off.
This best amplifier
, it is convenient for consumers who often and regularly visit settlements up to 150 km away, and in addition, listen to radio on long and medium waves. In addition, he has best characteristics gain in VHF bands and FM. In general, this best model radio amplifier.
YOU CAN BUY THE TRIAD 304 AMPLIFIER FROM RELIABLE AND PROVEN PARTNERS:
APPEARANCE. The fm signal amplifier for a car antenna is externally a plastic elongated black case measuring approximately 12 by 4 cm, 3 cm thick with rounded corners, model 302 is equipped with a gain adjustment knob, models 303 and 304 have a button for switching operating modes. On the reverse side it can be equipped with double-sided tape, with which it is attached to the car, more precisely, to its plastic parts - the dashboard, glass or glove compartment, depending on the installation location. On the front side you can see the Triad logo drawn in an oval. A 50 cm long cable with a plug, as well as a 12 volt power cable come out of the case. On the front side in the center of the case there is an LED that lights up when power is supplied to the amplifier. This is very convenient for the consumer, since the absence of light on the indicator indicates abnormal operation of the product. On the side there is an antenna input socket.
The amplifier is packaged in a cardboard box or blister, with instructions and basic instructions printed on the cardboard. specifications amplifier
WHY AND WHY - DETAILS. An FM signal amplifier for a car antenna helps receivers with insufficient sensitivity to isolate the signal from the background noise. If previously radio tape recorder manufacturers were chasing a sensitivity of less than 5 µV, now this parameter is often 50 µV or more. This is explained by the much more extensive network of radio stations in the West. And for us, 5 microvolts are still relevant in the vast expanses outside the Garden Ring.
Cassette tape recorders today can only be found in vintage cars, but modern cars are equipped with more serious systems that act as entire multimedia complexes capable of performing hundreds of different tasks. However, drivers love listening to the radio and watching TV on the road just as much as before. Unfortunately, most inexpensive radios with good functionality stop “catching” radio stations as soon as the car enthusiast leaves the city limits. The sound becomes distorted and jumpy, the image synchronization is disrupted, and noise appears. These signs indicate that the signal has become worse and soon you will have to drive along the highway in complete silence.
It’s worth saying right away that even the most advertised brand will not guarantee you a high-quality radio signal. Therefore, if you like to listen to the radio on the road, then buying a more expensive radio will not help. It is better to purchase a tape recorder with an antenna and supplement it with a special amplifier.
Antenna amplifier
You can buy an antenna amplifier for a car radio ready-made or make it yourself. When choosing a model, you need to focus on the following characteristics:
- the amplitude-frequency response must be uniform;
- the device must operate over a wide range, regardless of temperature and power;
- minimum “noise”;
- the gain factor should be about 15-25 decibels. A lower value will not improve reception quality.
It is better to buy amplifiers that can be installed on the antenna itself. If the device is located in the area of the antenna input, this may lead to an increased noise-to-signal ratio, which will undoubtedly affect the sound quality.
The most popular amplifier models
But they are not there. Example, amplifier of “domestic” production “Triad 304”. Such an amp costs about 650 rubles. Let's say right away the reviews about this amplifier are not the best. Judge for yourself what good can be in it if it is empty inside.
Most likely this miracle, registered under a Russian name, was produced wherever you think... And there are plenty of such amplifiers.
The antenna with a built-in amplifier “Bosch Autofun Pro” received positive reviews.
Only here lies the catch. Here are the photos for you. One antenna is “left” (on the left), and the second is the original (on the right). One doesn’t catch anything, but the second caught perfectly well 100 km away.
DIY antenna amplifier
An antenna amplifier for a car radio is a device that you can make yourself. For this, a classic two-stage circuit with 8 main resistors is used. Elements R1, R2, R4 and R6 in this case will stabilize changes in transistor VT1 if at some point a voltage surge occurs or the temperature rises sharply. All components must be selected so as to ensure maximum amplitude and frequency characteristics of the device.
In addition, amplifiers often use 2SC2926 bipolar transistors at frequencies below 1 GHz. This will reduce the noise level from the amplifier itself. All components of a two-stage circuit must be soldered on the board in the correct sequence. After assembly, you need to connect the amplifier input to the antenna input, and send the output to the radio receiver. To do this, use a cable with a resistance of at least 75 ohms. It is important to observe polarity.
It is better to organize power supply with a network with a voltage of 12 volts. After this, you can connect the made board to the radio (ANT output). So, the amplifier will start working as soon as you turn on the car radio.
For those who are curious, you can try to make such an amplifier. Once you try it, please post.
In custody
If we talk about what is better - a ready-made antenna amplifier for a car radio or a home-made one, then it is worth noting several advantages of each option. The finished device is inexpensive and you just need to connect it. In its turn, homemade device does not require special skills and knowledge, but at the same time allows you to get a clearer signal and reduce interference.
Loading...
