Modern auto electronics can turn the interior of an ordinary car into a mobile office, concert hall or even a cinema. Famous manufacturers of electronic components from Europe, Japan, the USA, South Korea and China are constantly fighting for the attention and loyalty of car owners. On the Russian market today there is a huge range of car audio systems, navigators and liquid crystal displays. television screens. But the quality of operation of all these devices directly depends on the state of the electrical signal arriving at their input, propagated by radio waves. The work of isolating the necessary signals from the air and transmitting them to a specific electronic device is precisely what an active car antenna is designed to do.
It is worth noting that the signal reception function for electronic systems A passive car antenna can also successfully perform inside a car, but the area of reliable operation of such a device is usually limited to city limits or the nearest suburbs. In addition, in large cities, even in urban conditions, a passive antenna cannot guarantee reliable reception of radio waves due to the negative impact on the signal quality of large reinforced concrete structures: buildings, overpasses, tunnels, etc.
The word “active” in the name of the antenna only means that the device has a built-in signal amplifier that is capable of picking up weak electromagnetic waves and “growing” them to an acceptable level. But for this purpose, the antenna also requires separate power. An amplifier in the antenna is necessary in cases where the car is located far from the transmitter. Taking into account the fact that transmitting stations are located mainly in cities or other large populated areas, and the distances between them in Russia can be very significant, the relevance of the task of amplifying the signal received by the antenna becomes quite obvious.
Types of active antennas
Based on their purpose, active car antennas can be divided into 3 types:
- radio antennas. Receive signals exclusively for the car receiver (radio);
- television antennas (TV antennas). In turn, active TV antennas are divided into analog and digital based on the type of signal received;
- combined antennas (universal antennas). These are multifunctional devices capable of receiving Various types signals - for audio, TV receivers, mobile phones, GSM or GPS devices, etc.
Interesting: There is another type of active car antennas - satellite dishes. These are specific devices that have not yet become widely used among motorists due to their high cost and complexity of both the equipment itself and the work required to install and configure it.
Based on the type of installation on a vehicle, active antennas are divided into:
- In-cabin. The interior antenna is usually installed on the windshield or rear window of the car. It consists of a small housing with a built-in amplifier in the shape of an oval, rectangle or circle (the most common type) and receiving elements (“whiskers”);
- external. An external active antenna can be installed on the roof, fenders or trunk lid (magnetic or mortise mount), as well as on the side door windows (clamp mount). There are whip and helical external antennas. The amplifiers of such antennas are usually designed as separate devices located inside the cabin.
The main advantages of in-cabin antennas include their compactness and reliability. Such devices are not exposed to aggressive external factors, so they retain their functionality and presentable appearance for a long time. In addition, the interior antenna is better protected from theft or mechanical damage.
External antennas have one significant advantage: they are more sensitive and provide better signal reception compared to internal ones. But external antennas also have many disadvantages: they are more bulky, spoil the appearance of the car, are difficult to install, and require additional holes in the body for laying cables from the receiving unit. In addition, external antennas are short-lived, as they are constantly exposed to negative environmental influences.
In addition to the adequate price and modern design of the device, consumers are mainly concerned with the quality of signal reception that the purchased unit can provide. Therefore, when choosing an active car antenna for a radio, you should first check whether it has two main operating modes:
- “city” - a mode with an increased level of noise immunity from the negative influence of industrial facilities;
- “turbo” - mode of maximum reception gain at a great distance from signal sources. Anti-interference protection practically does not work in this mode.
Criterias of choice active TV antenna more difficult. Much depends on the type of TV receiver installed in the car. Often specialized television receivers already have the necessary equipment in their configuration antenna device. If such a task (choosing a TV antenna) does arise, it is better to seek help from a specialist with special knowledge in the field of TV signal distribution and reception.
When mounting/installing an active antenna, the following aspects deserve attention:
- the connection of the active antenna amplifier to the on-board power supply network must be carried out through a separate fuse;
- It is not recommended to trim (shorten) or extend (extend) the standard antenna cable, as this may lead to deterioration of the received signal;
- the quality of the TV signal depends on the height of the antenna (the higher, the better), and the quality of the radio signal depends on the distance between the antenna and the underlying conductive surface - the roof or wing (the smaller, the better);
- when installing an active antenna, you must strictly adhere to the installation instructions, which must be included in the delivery package of a quality product;
- If the antenna is glued to the windshield, before installation, the glass must be thoroughly degreased, and protective film It is recommended to separate it from the adhesive layer last;
- to increase the antenna reception efficiency in all frequency ranges (taking into account different wave polarizations), the elements of the interior antenna must be placed on the glass perpendicular to each other - one horizontally and the other vertically;
- The antenna cable along the entire length from the antenna to the device should not have sharp bends. Where it passes through car bulkheads, rubber bushings must be used.
Conclusion
The task of choosing the right active antenna for a new car gadget seems simple at first glance. The variety of offers on the market also increases the difficulty of making the right decision. Therefore, before purchasing such a device, it is always useful to consult with a specialist.
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This interesting post will tell you about the purpose of strange antennas and devices that are installed on government vehicles and accompanying motorcade vehicles. So, let's read detailed description all such devices during the continuation of fasting.
Where did it start
The appearance of strange antennas and other devices on car roofs dates back to the times of the USSR. In those days, the KGB and other intelligence services used them to ensure confidential communications, wiretapping, etc. They were used in the army and the Special Purpose Garage (GON) - when transporting senior officials of the state.
Over time, in the 90s, special devices began to appear on the cars of crime bosses. They became widespread after they started blowing up cars with big shots in them everywhere. The latter introduced the fashion for installing special communications antennas that protect against radio-controlled explosive devices.
A good example
It is quite problematic to find out what is actually in the cars of the presidential motorcade, for example. But one of the cars in Barack Obama's motorcade partially reveals the topic of ensuring safety during movement.
This is an electronic warfare vehicle that the State Department and the Secret Service have. It is used to suppress air or surface missiles, jamming and/or radio interception, and blocking radio-controlled explosive devices. The government “tops” of Ukraine also have similar antennas and devices. In particular, the president. There is always at least one car with “horns” in a motorcade.
Plus, on the Mercedes in which Yanukovych himself drives there is, at first glance, an ordinary antenna. But she is unusual...
Buckets or black pots
Most people are interested in knowing what kind of black “buckets” can be found on government and simply expensive cars. Some people confuse them with flashing lights, supposedly covered with covers. By the way, when in 2011 the media wrote about the motorcade of People's Deputy from the Party of Regions Yuri Ivanyushchenko (in narrow circles - Yura Enakievsky), the journalists confused the “buckets” with flashing lights. Already after publication as “P.S.” it was added that these were not flashing lights at all, but supposedly “The Veil”.
"Veil". You are unlikely to be able to find the exact characteristics and purpose of this complex on the Internet. However, how do you find out the cost? And the company that sells and installs such “devices” in Ukraine is extremely non-public. However, it often appears in tenders for the purchase of special equipment for the Security Service of Ukraine and other departments. Its name is the scientific production center “Infozahist”. The main principle of the SPC is not to name its clients and customers either explicitly or indirectly, since even the very fact of contacting a customer company can be used by ill-wishers for their own purposes.
The radio-electronic complex "Pelena" is designed to protect against radio-controlled explosive devices, as well as to protect technical information. In addition, this complex serves to block cell phones. The kit includes 6 antennas ( different types, including “buckets”) and a metal monoblock (often placed in the luggage compartment). The cost of such a complex is about 20-25 thousand dollars.
It is worth noting that there are other complexes that perform approximately the same functions as the Veil. There are foreign analogues. There are productions in the CIS. For example, sometimes you can find complexes from the Design Experimental Bureau of Radio Equipment “COBRA” on VIP cars.
Stealthy Antennas
In the CIS countries they are represented mainly by both old and new “Kavkaz”, “Karat”, “Angstrem” and “Rosa”. All these are special communications complexes, which, if you go into detail, have significant differences. One of the first to use them is Leonid Ilyich Brezhnev. It is on his car that you can see half-meter antennas installed at an angle from the Rosa government mobile radio communication system.
The use of each of these complexes is to ensure secure communications between heads of law enforcement agencies and government officials. To make it clearer what special communications are, let’s take the “Caucasus” as an example (and at the same time remember the antenna on Viktor Fedorovich’s Mercedes).
"Caucasus". Divided into 7 code groups. Depending on the type, it can provide both simply secure telephone and documentary communication, and communication with moving objects (airplanes, ships, etc.). It comprehensively uses wired, shortwave and satellite communication channels. The Kavkaz-7 version is a secure telecode communication channel with the aim of immediately conveying information about a nuclear attack to top officials of the state, regardless of their location and broadcasting it to the centralized combat control system decision taken(sanctions) on organizing retaliatory actions (use of nuclear missile weapons).
On cars, the presence of the “Caucasus” can be recognized by an antenna in the form of a 25-30 cm pin with a triangular base, installed at an angle of 60-70 degrees.
The antennas of other complexes look similar to the Caucasus, but still different. However, we don’t have a circle of radio amateurs here, so we won’t get into the details. It is important to note that you will not be able to install such a complex in your car. Firstly, the antenna is the tip of the “iceberg”, and the “iceberg” itself in the form of a huge suitcase (let’s call it that) will not fit into all cars. Secondly, a person with a service weapon must always be in a car with special communications. And thirdly, such “pleasure” is not cheap and cannot be used for personal purposes without special permission from the relevant authorities.
Horns
Small “horns” on the roof of a car may indicate the presence of an ethereal ground digital television DVB-T(2). At first, this luxury was found on government cars and the cars of intelligence service leaders.
Over time, businessmen also caught up and wanted to have digital TV. Price - about 1000 UAH.
Washer
Initially, this type of antenna was used for use in confidential crypto-secure communications networks for intelligence services and higher authorities. Over time, it also migrated to the cars of civilians, including taxi drivers (there are many of these in Russia).
The advantage of such an antenna is that it has a circular radiation pattern in the horizontal plane - you can communicate with “subscribers” using mobile radio station, regardless of the location of the vehicle. On civilian vehicles it can be used as a GSM-3G antenna, which improves communication quality and mobile internet from a regular 3G modem. Price - from 300 hryvnia.
Plate
Occasionally you can see “plates” on cars of this kind. Such antennas are used for radio monitoring and radio control - detection, direction finding and analysis of radio signals, which is necessary to ensure public and national security, as well as control of frequency distribution at the state level.
Often direction finders are hidden under roof boxes. So don't be surprised if you see a huge SUV and/or a strange-looking minibus with a box on the roof. This does not mean that its “owner” does not have enough trunk space. Maybe there's a direction finder there. Or is it really that the entire trunk is always full of equipment...
I hear everyone, I see everything
To summarize, it remains to add that the above special communication devices allow not only blocking explosive devices, but also eavesdropping on anyone and, of course, jamming signals. Anyone too. We hope that after reading the article, you will no longer wonder what kind of “buckets” and “hedgehogs” are on the roofs of expensive cars. Of course, we have examined only a small part of the existing special communications equipment; only this photograph of a car from the US Presidential Security Guard makes it clear that behind the antennas on the roof of the car is hidden a whole bunch of equipment, the existence of which we may not even suspect.
In conclusion, I would like to make one more amendment. The presence of any of the mentioned attributes of special communication does not always indicate that it really is in a particular car. The Internet is full of offers for the sale of dummies, which, by the way, are also sometimes found on expensive cars with supposedly “difficult” owners. In Russia there are enough unique people installing pseudo-Pelena on VAZs.
How to distinguish dummy systems from genuine systems? If you don't look closely, you can get confused. But you don’t have to be an expert to understand the main thing - mostly real antennas are installed on cars that rarely drive unaccompanied or have non-government or simply “thieves” license plates. Well, the brand of the car, due to our mentality, also plays a role.
06.06.2016
Traveling without a tape recorder in the car turns into real boredom. It’s much more interesting to tune into your favorite radio station and plunge into the world of listening to your favorite music. Indeed, it’s more comfortable to move even along a boring country road. But one of the main problems for car enthusiasts is the choice of antenna. Many car enthusiasts often do not know which characteristics are the most important, as well as what to pay attention to when choosing. Let's look at these questions in more detail.
Purpose and characteristics
The task of the antenna is to convert electromagnetic waves coming from various sources into a special signal in the form of electric current. The reverse process is also possible, when the electrical signal is converted into EM waves. This option means that the same antenna can perform several functions - capture a signal and transmit it. If the antenna itself is not capable of catching a signal, then no amplifier can help it.
The first thing you should pay attention to is the size of the antenna. It is known from the physics course that electromagnetic waves have two main characteristics - length and polarization vector (the parameters depend on the magnetic and electrical components). When it comes to the electrical part, waves are divided into two types - horizontal and vertical. Radio stations operating today operate on the principle of vertical polarization. In turn, stations that broadcast television, on the contrary, operate on the principle of horizontal polarization. When choosing an antenna, you should take into account its parameters, which should be commensurate with the wavelength. As for the polarization of waves, not only the size is important here, but also the correct choice of position of the product.
The relationship between the size of the antenna and the length of the received (sent) waves is a whole science. To clarify this point in simple words, then the requirement is due to the need to enter into resonance with EM vibrations. Only in this case will the antenna work with maximum efficiency and convert the EM wave into the voltage of the required value. Subsequently, the electric current can be amplified and converted in the radio tape recorder (receiving device).
The concept of tuning is important for an antenna, because in this case the latter will be able to selectively approach the reception of certain signals. On the other hand, the final selection process lies with the receiver. If you believe the technical justifications and experiments conducted, then the most effective are antennas that have the usual pin shape. In this case, the length of the device should be equal to a quarter of the wavelength of the middle part of the range.
- 1. Outdoor antennas.In this case, the signal received by the antenna is sent to the receiving device without loss of quality. But to achieve such results, the antenna must be matched with the feeder (cable), and the connecting cable must be matched with the radio. These conditions are not difficult to fulfill if the antenna is ¼ of the length, the cable resistance is 75 Ohms (for a television cable), and the receiver input is correctly calculated and correctly designed.
The quality of wave distribution in the air is closely related to the wavelength. This is how medium and long waves bend around the surface, that is, they are distributed globally. As for short waves, propagation occurs due to multiple reflection. There are also ultrashort waves, which are the weakest and only work within line of sight. Moreover, each type of wave has its own purpose.
For example, long and medium waves in car antennas are only needed to receive radio signals. Here, there is no need to produce any special antennas, because such signals have sufficient power. If the antenna has caught a signal, it will be of high quality (the principle of such reception is often called “on the nail”).
The principle is similar when working in the short wave range. The only difference is that here communication also becomes available. In addition to the amateur communication option, HF is allocated a “piece” for owners Vehicle. The operating frequencies here are 26.97-27.85 MHz. Such ranges are called CB (CB).
Most modern antennas are configured to receive ultrashort waves. In this case, the reception range is limited to frequencies of 66-108 MHz. Here it is worth highlighting two categories of frequencies - “Soviet”, which was adopted back in the USSR (66-74 MHz) and “foreign”, operating in the range 88-108 MHz (FM waves). The name FM stands for “frequency modulation” or frequency modulation. It turns out that when designating the type of antenna, we are guided by the wavelength, and abroad - by the type of its transmission. At the same time, the subtleties of the work remain unchanged.
- 2. Internal antennas.If the antenna is internal, then it can be of two types - removable and stationary. In the latter case, the product is glued into glass. The main convenience of internal devices is reliability. They are difficult to break or steal. Another thing is that the signal quality of such products leaves much to be desired. The problem is that the antenna “antennae” are horizontal, although the signal arriving at the antenna has a vertical direction. In addition, in city conditions the signal changes regularly, which complicates the “life” of the antenna. But once you leave the city, you encounter a number of problems.
To promote and popularize the product, manufacturers supply antennas with special amplifiers that improve the signal quality. On the other hand, if the antenna is unable to receive the signal, then the amplifier will be useless. Antenna amplifiers are good when there is a long wire between the antenna and the receiver (often this is what causes the signal quality to deteriorate).
It is believed that if the wire length is up to 5 meters, then when driving outside the city (when there is no normal signal), the amplifier is ineffective. All it can do is increase noise, and within the city, add interference. That's why many antenna developers install special city-highway switches. In fact, the principle of operation of such a system is simple - when switching to “city”, the amplifier turns off.
Practice shows that best amplifier is a high-quality antenna, and the best choice from antennas - installation of an external product (taking into account polarization and wavelength). If we consider the FM range, then the best sound quality can be achieved from a pin having a length of 75 centimeters.
The main disadvantage of outdoor antennas is that they are easy to break. That’s why, when choosing such a product, you should focus on the height of the garage and the design features of your car. It is also worth thinking in advance about the intricacies of running the cable to the receiving device, the installation location and other points. The best option cable - the use of a shielded and solid product in which there are no solders or joints along the entire distance, from the receiving device to the antenna itself.
- 3. Antistatic antennas.Separately, it is worth highlighting another type of device - “miraculous” antennas, which, according to manufacturers, are capable of removing static electricity from the car body. A similar innovation in the automotive industry was observed in the aviation sector. So, on airplanes there are special “tassels” on the edges of the wings, the task of which is to eliminate static charge. The principle is the same here. But this does not work in cars, because to avoid the appearance of a static charge, the car must move at the speed of an airplane. In addition, antistatic antennas are fixed with double tape, which, together with the paint and varnish coating, makes the process of removing static impossible.
Antenna parameters
- Wave resistance.Standard antennas that operate in the CB band have a wave impedance of 50 Ohms. In some cases, they are connected to the receiving device via a coaxial cable that has a resistance of 50 Ohms (usually PL-259). The personal wave connection of most antennas has a volume of 50 Ohms. That is why a matching device is connected between the feeder and the antenna. The main difficulty is that it is impossible to measure the characteristic impedance using a special device.
- Number of channels or bandwidth.This parameter characterizes the frequency range in which the antenna is capable of operating without tuning. The difficulty is that the SWR parameter at the bandwidth limit is often not specified in the parameters, so compare bandwidths different models antennas is not possible. But there is a way out. Due to the fact that the grid step between the channels is 10 kg, it is possible to determine by the number of channels throughput antennas. The formula is as follows: Bandwidth (kHz) = Number of channels * 10 kHz.
- Gain.This indicator shows how many times the signal at the antenna output changes in comparison with the same indicator of the reference device. During the measurement process, a signal from one radio station is taken into account. Antenna gain measurements are given in relative units. The problem is that manufacturers do not always specify this parameter on their devices. Experts recommend that when purchasing an antenna, you should focus on the gain, but do this with great caution. And here it is worth considering the size of the antenna. Thus, long products are characterized by greater reinforcement. Special antennas that have an extension coil provide greater gain than antennas of the same size.
- Conducted power.By this parameter one can judge the maximum power that the transmitter can have if this antenna is used. If the maximum permissible power is exceeded, breakdown or thermal destruction may occur. For industrial-type antennas, the maximum power limit is 10 W.
- Wind resistance.This criterion is important, although many car enthusiasts ignore it when choosing an antenna. The wind resistance indicator can be used to judge at what wind speed the antenna can be destroyed. It is especially important to pay attention to this indicator in regions where hurricane winds occur. In addition, antennas that are mounted on a magnetic base are susceptible to wind.
Not a single one, even the most modern and sophisticated media installation, will provide high-quality sound radio if the input signal does not meet its technical parameters.
An antenna is used to catch signals; there are two types of devices: Passive antenna. Installed in the cabin or on the body, the simplest and cheap option. Advantages – low price.
Disadvantages – unsatisfactory signal quality. Currently, car enthusiasts listen to stations mainly in the FM range.
These waves have the proper quality and power only within the line of sight of the transmitter and the consumer.
As soon as the car leaves the city, the signal deteriorates significantly; the radio reacts negatively not only to every kilometer removed, but also to every rotation of the antenna in relation to the emitting tower. Active car antenna.
Has a special additional electronic unit. The tasks of electronics include automatically amplifying a weak signal, suppressing noise, and improving sound quality.
The electronics independently selects the optimal signal modes to ensure maximum music quality.
The most modern cars have the ability to display television signals, this greatly improves driving comfort, especially over long distances.
To receive a television signal you will need a car satellite dish.
By the way, most radio stations also produce satellite broadcasts.
One antenna can provide a signal to several multimedia devices.
How does a car satellite dish work?
Difficulties in receiving a satellite signal - the need to fine-tune the satellite position.
The car constantly makes various turns, and this causes the lack of signal.
An active car antenna for radio signals does not have such a dependence; its technical part is much simpler.
Accordingly, quite a few different companies are involved in the production of these devices; their products have only minor differences.
Today's satellite dish is not at all like the usual parabolic dishes; it is flat and fixed in a “lying” position on the roof of the body.
The special sealed housing guarantees full protection internal equipment from moisture and dust, can operate under significant temperature fluctuations and in any weather.
A receiver may be included in the package.
During installation, there is no need to make special mounting holes in the body; the cable is inserted into existing holes.
Fastening is carried out on railings - the warranty on the body is not lost. Many other useful tips for installing auto accessories you will find in.
A car satellite antenna can only be produced using modern equipment by companies with highly professional specialists in various specialties.
Well-known global brands guarantee high-quality reception at any speed, while changing the trajectory of the car does not have a negative impact on the quality of the signal.
The antenna must have minimal aerodynamic drag and a high speed of adjustment to the satellite, taking into account changes in the position of the vehicle.
Modern models use the phased array principle in combination with a fast electromechanical drive.
Up to two hundred mini-signal receivers are installed on one surface; the electric drive rotates the plate 180°.
The rotation speed can reach 30° per second, the speed is much higher than the car passing the sharpest turns - the signal is always received steadily.
Another useful information you can read about it here.