Thanks to the dynamic development of television broadcasting in the modern world, there is probably no person who has not encountered antennas. In order to watch their favorite TV programs in the best quality, the user needs to connect an antenna to their receiving equipment. And here the question arises: which antenna to choose, active or passive? In this article we will consider in as much detail as possible the features of each antenna, as well as their scope of application. But first of all, it is necessary to give a detailed definition of the term “antenna” itself and briefly describe the history of its creation.
An antenna is a special device whose main task is to receive or emit radio waves. It converts electrical current fluctuations into radio waves or vice versa. As can be seen from the definition, antennas can operate for reception, transmission, or reception-transmission. The simplest antenna operation scheme is as follows: a television or radio device produces a signal, which is amplified and transmitted to the transmitting antenna. The antenna, in turn, distributes this signal in the form of radio waves. During the propagation process, the waves reach receiving antennas, which record them and transmit them for processing with subsequent output to end devices in the format of the original signal. Each stage of antenna operation may be accompanied by certain interference arising from other radiation sources or terrain features.
The creator of antennas was the famous German physicist Heinrich Hertz. It was he who, in 1888, made the first such device to confirm the presence of electromagnetic waves. Of course, since that time, antennas have changed significantly both externally and functionally. Today we will only touch on the classification according to the level of antenna activity, although there are quite a large number of different types and types of antennas.
Passive antenna
A feature of any passive antenna is that it picks up and receives a signal solely due to its geometry (shape). Accordingly, the larger the area of such an antenna, the more reliable the signal will be.
Passive antenna
The advantages of such an antenna can be considered:
- The absence of its own interference and interference due to the fact that in such an antenna, in fact, there is nothing to be aimed at. After all, its design does not contain any elements that could generate electromagnetic radiation.
- Exceptional ease of installation and operation. All that is required is to correctly orient the passive antenna on the terrain.
- You can even make a passive antenna yourself from scrap materials. As a rule, the entire structure of such an antenna is a metal frame with a transmitting cable or wire.
- A passive antenna does not require a separate power source.
- Finally, it is worth noting the low cost of a passive type antenna.
However, a passive antenna also has disadvantages:
- It is susceptible to various types of interference, and the signal quality greatly depends on its location;
- When installing a passive antenna, you have to carefully select a location and carry out careful orientation, especially if the installation takes place in an area of poor reception.
- Typically, a passive type antenna is installed at a fairly high altitude - up to 10 meters, which requires the installation of a special mast, additional reinforcements for it, etc.
- Passive antennas must provide a sufficiently large reception area, which makes them bulky and inconvenient, for example, indoors.
- The quality of the signal can be influenced by a huge number of factors: buildings, trees and terrain, as well as weather conditions.
Thus, it is recommended to install a passive antenna only where there is a fairly strong signal area and there is no need for additional amplification. Passive antennas come in both indoor and outdoor types. As a rule, it is installed in apartments located within the city, where the signal level is usually quite high. However, in suburban areas, on highways, etc. Active antennas are usually used.
Outdoor antennas
External receiving devices are distinguished by high power, which is provided by a special design, and in some modifications, built-in amplifiers. Outdoor antennas receive signals from a source at a distance of up to 50 kilometers.
Possible interference from obstacles located in the signal path should be taken into account. Metal structures, buildings, and structures reflect or distort waves. Therefore, most experts recommend purchasing equipment with built-in amplifiers. The top external antennas include 2 models.
Important! Powering the active antenna from the t2 receiver reduces the life of the power supply. The load on the set-top box doubles, and with a long cable length triples
Remo "Kolibri-A-DX Deluxe"
The signal receiver is placed on a mast, which is included in the delivery package. This configuration improves channel acceptance. The built-in amplifier helps to receive TV signals even at considerable distances from towers. Thanks to Remo’s successful design, Kolibri-A-DX Deluxe picks up digital signals even in areas where there are no towers within line of sight.
In positive reviews, buyers note stable reception and good signal quality. The device is easy to set up. Assembly and installation takes 10-30 minutes. The external structure is protected by powder coating, which provides protection against rust and exposure to chemicals.
The delivery set includes an external power adapter and a connection cable (6 meters long). Some customers have had problems adjusting the external amplifier.
Remo "Dvina-DX"
The powerful antenna ensures reliable signal reception up to 50 kilometers. The device is equipped with a built-in amplifier and a 12-volt power adapter. The main advantages of the TV antenna are excellent reception, low price, reliability, and ease of use.
All components are made of high quality materials. The aluminum support rod is lightweight and durable. External elements that receive signals are treated with an anti-corrosion coating. The fastener securely fixes the TV antenna. The disadvantages include a rather complicated installation, as well as the need for adjustments for high-quality channel reception.
Active antenna
A feature of the active type antenna is that the captured signal passes through special converting devices and only then directly to the receiving equipment. All kinds of amplifiers, noise suppressors, decoders, etc. can act as converting devices.
Active antenna
Such devices can be mounted either directly on the antenna itself or outside it. They are usually powered through a household electrical network, but in some cases an autonomous power source in the form of rechargeable batteries or batteries can be organized.
Advantages of active antennas:
- They can be made in almost any size and shape.
- Active antennas can be installed almost anywhere - indoors or outdoors. The quality of work is little influenced by both the terrain and interference from trees, buildings, etc.
- Even a low signal level is not a hindrance for an active antenna: it is amplified by additional equipment.
- Many active antennas have adjustable gain and noise reduction levels.
- Interference that may be present when using an active antenna is also removed by special noise reduction devices.
At the same time, the disadvantages of active antennas can be considered:
- Their relative high cost.
- Technical complexity: after all, an active antenna uses a large amount of electronic equipment.
- For correct operation of the active antenna, a constant power source is required.
- In some cases, the cause of electromagnetic interference may be the antenna's own equipment. However, they are also eliminated with special “noise suppressors”.
- Sometimes an active antenna is quite difficult to install and configure.
- Due to the large amount of electronics, an active antenna has a lower degree of reliability compared to a passive one, in which, strictly speaking, there is practically nothing to break.
Thus, it is recommended to install an active type antenna in places with not very reliable or even poor signal levels. For example, outside the city, in mountainous and wooded areas, etc.
What to choose - active or passive
When choosing, you can rely on the reviews of your neighbors, but it is best to evaluate the following indicators:
- Distance to TV tower. You can find it out in 1 minute using the CETV map. If the distance is no more than 10-15 km, there is no urgent need to purchase a TV antenna with an amplifier. A reliable passive device will also help here.
- Antenna location. If it ends up in a low-lying area, in a remote urban area, or without the ability to be oriented towards the repeater, you definitely need to use an active one, even in an indoor version.
- Signal level. If it is high enough and the power is high, the active antenna is harmful: the overamplified TV signal will become unreadable for the tuner. If it is critically too weak, the injector is useless: it simply has nothing to strengthen. The useful signal is always received by the design of the television antenna, and if its own gain does not help, even the most powerful injection unit will not help.
- Number of connected TVs. It is easier to distribute a TV signal to three or more TV receivers using an active one.
We have written convenient instructions for choosing the type of digital terrestrial antenna; we recommend that you act in accordance with it.
The main differences between active and passive antennas
The main difference between active and passive antennas can be considered the presence or absence of additional electronic equipment , which amplifies the signal and suppresses noise.
As a result, active and passive antennas differ in the installation method, requirements for the presence of a power source, as well as the qualifications of the technician who installs the antenna. If almost any person can install a passive one, then in most cases only a qualified specialist can be involved in the correct installation, configuration and debugging of an active type antenna.
Hi-techComment
Is it worth buying the advertised Japanese antennas for 100–200 channels?
There are often advertisements for some fancy devices that are supposedly capable of receiving dozens of TV channels even at the bottom of a coal mine. Should you trust this advertising?
As of the second quarter of 2021, only two packages (multiplexes) with 20 free channels are available for free:
- RTRS-1 (Channel One, Russia-1, Match-TV, etc.);
- RTRS-2 (Ren TV, Spas, Domashny, etc.).
The broadcast of 10 channels of the third multiplex, designed for broadcasting local TV channels, has been postponed for economic reasons in most parts of Russia, with the exception of Moscow and Moscow Region, as well as Crimea and Sevastopol (where the third package, along with transmission equipment, was “inherited” from Ukrainian and local channels are already broadcasting digitally).
Thus, even in an ideal case, the subscriber will not be able to receive more than 30 channels. Even in border regions, where it is sometimes possible to receive multiplexes from neighboring countries (for example, Ukraine or Belarus, where a complete transition to digital TV took place long ago), there is no need to talk about hundreds of channels.
In addition, the technical characteristics of these Japanese “super antennas” are also questionable. Most of them in practice turn out to be ordinary cheap “slingshots” of two telescopic antennas for receiving MF. Digital TV broadcasts in a completely different range.
Theoretically, you can even try to catch a “digit” with this slingshot, but this method will only work at a distance of a few hundred meters from a very powerful repeater, that is, where a TV signal can be caught on a piece of wire. Even if the Japanese one is equipped with a “steering wheel”, like that of the UHF, it is nothing more than an indoor device of far from the best quality.
Moreover, there can be no talk of “self-tuning at the station”, “decoding encrypted channels” and the ability to catch a signal almost from mobile communication towers.
Do you think a super device with 100 channels is true or a scam?
True! Divorce!
What is the difference between passive and active?
So, all indoor antennas are divided into two types: passive and active. Representatives of the first species pick up the signal using their design. Their main advantage is that they do not need to be connected to the mains, nor do they need to be equipped with additional amplification equipment. Many users note that when using passive elements there is no signal interference.
But such models cannot always cope with their task. In this case, an indoor active antenna is installed. Better signal reception is achieved with the help of an additional device. This device can be installed in the element body or come separately. In this case, the active antenna is powered using the electrical network.
Like every device, the active part has its drawbacks. One of the main negative aspects is the poor quality signal. It occurs due to a low-quality amplifier. Such cheap Chinese models are widespread on the market. The signal can also be distorted from a very sensitive amplifier. Distortion occurs in the area of reliable reception, where the use of an additional amplifier is not required.
(1 rating, average 5 out of 5)
Indoor antenna: active or passive
In cases where an indoor antenna is used to receive the signal, the choice must be made based on:
- Directions where the windows face. The walls of the house jam the signal, so, as a rule, they try to install indoor antennas in the window opening. If the window faces the repeater (at least with an accuracy of 180 degrees), you can use a passive one. If on the opposite side - active.
- Signal level. It can be assessed by the sensors that modern TVs are equipped with. If the level is 50% and above, passive is sufficient; from 15 to 50%, active is required. If the signal is below 15%, you must either install an external TV antenna, or look for another way to watch television (satellite dish, connection to a shared TV, cable TV, Internet, etc.).
If you are looking for a good indoor option, then we recommend you the TOP 8 best indoor antennas according to the editors of ProDigTV.
Indoor antennas
Internal antennas receive digital signals at maximum distances of up to 30 kilometers. Despite the worse reception quality compared to external and satellite devices, they have such advantages as compactness and low price.
Indoor equipment is easy to install. There is no need to climb onto the roof, look for the right direction, select fasteners, or install external structures. There is no need to fear that the device will be cut down like a Christmas tree on New Year's Eve.
The optimal location for an indoor TV antenna is next to the window facing the repeater
You should take this circumstance into account, buy network cables, as well as wires for connecting to the TV, of sufficient length
The leading position in the indoor TV antenna market is occupied by the Remo company. The rating includes several devices with the best price and high quality.
Remo BAS-5310USB Horizon
Are you choosing an indoor antenna for DVB-T2? Start the comparison with the leader of the rating. The original design will decorate any interior. Compact mounts allow you to place the equipment in any area. The receiving module picks up signals in the UHF range 21-69. The built-in amplifier is an additional advantage of the model.
Almost all buyers confirm the high quality of reception. A modern antenna even catches reflected signals. The device is connected to a USB connector. The durable housing reliably protects components from mechanical and impact damage. The device weighs only 230 grams. A 5 volt adapter is included in the package.
Harper ADVB-2120
The second place is occupied by the products of the famous company Harper. The antenna received a large number of positive responses. The device receives frequencies in the range 87.5-862 MHz. This model is suitable for any TV. The design has a unique design and compact shape.
There is no external network adapter (power supply). Electricity comes from the TV (set-top box), which imposes certain restrictions. The Harper ADVB-2120 can be placed on flat or inclined surfaces. The torus shape allows the Harper to be hung on a cornice or shaped mount. The model is considered one of the best due to its technical characteristics and low price.
Remo Inter 2.0
The universal model takes third place in the ranking. The device receives 10 analog and 20 digital channels. Thanks to a unique control system, you can independently select the level to amplify the signal. This feature ensures maximum transmission quality. An additional bonus is the reception of 3 radio channels.
One of the undoubted advantages of the device is its beautiful ergonomic design. Assembly and installation take only a few minutes. The external adapter is made of high-quality composite materials, the cable is well insulated. The wires connecting to the TV and power supply are approximately the same length. The model is equipped with a built-in amplifier.
When do you need a TV antenna?
In most cities, the “horns” of the antenna above the TV (as well as the shamanic actions to set it up) have long ago become a thing of history - cable television has almost completely replaced over-the-air broadcasting. But civilization has not yet penetrated everywhere into country houses and, especially, into holiday villages, but I still want to watch TV. And there are plenty of cities on the map of Russia that have not yet fallen into the web of cable TV. And here television antennas are still relevant.
But the conditions for receiving a television signal are different everywhere - from one place the television center tower can be seen with the naked eye, from another it is tens of kilometers away. In all these cases, different antennas will be required. And so that the purchase does not disappoint, you should find out the reception conditions at the place where the antenna is installed, decide on its characteristics, and only then go to the store.
How to find out the conditions of admission? It’s good if the television center and its transmitting tower are visible from the window, then the question disappears. And if the television center is several tens of kilometers away, how then can one determine in which direction and how far away the nearest repeater tower is? This can be done using the interactive map of digital terrestrial television broadcasting on the website of the Russian television and radio broadcasting network. You just need to select your region on the map and zoom in to the desired scale. The map shows both existing and under construction towers. In addition, you can simply click the mouse pointer at the desired point on the map and in a separate window the distance and direction to the nearest towers - both existing and those under construction - will be displayed.
How Antennas Work
Terrestrial television is transmitted over the air in the form of radio waves of various frequencies. Moreover, this is true for both analog and digital signals. Antennas, in turn, are necessary to catch them.
The metal parts of the antenna, finding themselves in the electromagnetic field formed by the television signal, are “guided”. They generate a current that flows into the TV. It is then converted by the device into a video and audio signal that the viewer can understand.
In principle, the operation of the antenna device is very simple. However, this mechanics creates the need to place the receiving equipment in such a way that the current is induced in it most efficiently. It is not enough to simply place a metal “slingshot” on a window or place it on the roof - you also need to deploy it so that the “blades” best receive the signal.
Terrestrial television - broadcast formats, signal transmission
Free television channels, which we watch by receiving the signal on indoor or outdoor (street) antennas, are the same terrestrial television. A television (radio) signal is transmitted from a repeater into the air, that is, into the surrounding space, via electromagnetic waves. We, as users, use terrestrial antennas to receive this television signal.
To transmit a television signal, meter VHF (VHF) and decimeter UHF (UHF) waves are used.
Digital terrestrial television of the DVB-T2 standard is broadcast via UHF decimeter waves. Accordingly, in order to watch “digital” you need to have the “correct” antenna. It must be either all-wave (VHF + UHF) or UHF decimeter range. With an antenna that receives only VHF band, watching digital terrestrial television will not be possible.
MV and UHF are ultrashort wave (VHF) bands dedicated to the transmission of television signals. Frequency band from 48 to 862 MHz with a conditional division into 5 ranges combined into two groups: - 1-12 channels meter or VHF, bands I, II, III (47-160 MHz); — 21-60 UHF channels, otherwise UHF (UHF), bands IV, V. (470-862 MHz).
Broadcasting of analogue terrestrial television occurs in both bands, both in HF and UHF. Previously, it was planned to turn off analog TV in Russia by the end of 2015, but now the deadline has been pushed back to 2021.
TV antennas in questions and answers
What are TV antennas for?
The antennas are designed to receive television signals in the frequency range 48-862 MHz. What types of television antennas are there? Antennas are channel antennas, designed to receive one channel. Band, designed to receive one television wavelength range. All-wave, designed for reception in all ranges of television waves. All-wave antennas are usually combination antennas consisting of several antennas structurally connected together. Television antennas also differ in type, for example, log-periodic, wave channel, etc. Antennas are also internal and external, with a built-in amplifier - active, and without an amplifier - passive.
How far is the indoor antenna from the TV? Indoor antennas are the simplest type of antennas, their vibrators are not even quarter-wave in size, but smaller, the gain of such antennas is, on average, less than 3-4 dB, so they can be effective at a distance of no more than 10 km from the television center. The effectiveness of indoor antennas directly depends on the location of the antennas in the room, the thickness and material of the walls, partitions, and the size of the building openings. The built-in amplifier in some cases can improve the receiving properties of indoor antennas.
Which antenna picks up a TV signal well? For good reception you need a multi-element antenna with a low-noise antenna amplifier. This antenna has a narrow radiation pattern and high gain.
Antenna - the key to free TV This phrase is an advertising gimmick for selling digital television antennas. This is not a hoax, the fact is that any UHF antenna is the key to free viewing of digital television, and this phrase does not mean anything else!
Which antennas are better, log periodic or wave channel? Log-periodic ones have a more uniform amplitude-frequency response, but their gain is less than that of wave channel antennas.
Which antennas are better to use, active or passive? The use of antennas is largely determined by reception conditions. Passive antennas are more preferable because they are highly reliable. Thus, it is better to install a passive antenna with high gain than an active one with small dimensions.
What is the unevenness of the amplitude-frequency response (AFC) of an antenna? Television antennas operate in a wide range of frequencies (except for channel antennas). The antenna gain at different frequencies may vary. The difference in gain in dB at different frequencies will characterize the unevenness of the antenna's frequency response. The better the antenna is designed and correctly manufactured, the less uneven its frequency response is. The quality of matching of the antenna with the feeder has a great influence on the frequency response.
What determines the size of the antenna and its vibrators? The size of the antenna is determined by the wavelength, half-wave vibrators, quarter-wave vibrators, etc.
What is the characteristic impedance of wave channel antennas? The characteristic impedance of wave channel antennas is 300 Ohms. To connect this type of antenna to the feeder, a matching transformer is used.
What is the characteristic impedance of log periodic antennas? The characteristic impedance of log-periodic antennas is 75 Ohms. To connect this type of antenna to a feeder, a matching transformer is not required.
What is the characteristic impedance of a television coaxial cable? The characteristic impedance of a television coaxial cable is 75 ohms. The television cable has predominantly a foamed dielectric, a copper-covered central core, and it contains a compromise solution between flexibility and losses. In addition to television, it is also used in video surveillance.
What other characteristic impedance does a coaxial cable have? Coaxial cable with a characteristic impedance of 50 Ohms is widely used. This type of cable is used in various fields of radio engineering. A cable with a characteristic impedance of 50 Ohms has a solid dielectric and minimal losses, has high strength and maximum capabilities for transmitting high-power energy.
What happens if you use a cable with a characteristic impedance of 50 ohms to connect TV antennas? The coordination of the antenna with the feeder will be disrupted and part of the electromagnetic wave energy received from the air will not reach the connected load, for example, a TV.
How does the gain of an antenna depend on its size? The more elements in the antenna, the greater its gain.
What amplifiers are best to use for over-the-air antennas? Antenna and mast amplifiers are most effective for receiving signals in areas of poor reception. It is best to use amplifiers built into the cable for household antennas; they are enclosed in a metal shielding housing and protected from lightning strikes. The amplifiers, made in the form of a board and mounted in the antenna junction box, last until the first thunderstorm.
When is the best time to use an indoor antenna? The use of indoor antennas is determined by the reception conditions. If the signal is strong enough and there is direct visibility to the transmitting center, then the use of indoor antennas is justified. Reception of reflected signals will be unstable. Digital television has expanded the scope of indoor antennas.
Which one to choose?
Active antennas are most often chosen in the following cases:
- Installation outside the city, in regions remote from transmitters;
- Use in areas with an increased amount of external interference (near railways, highways, high-voltage equipment);
- Installation in rooms with thick walls, including reinforced concrete houses;
- Placement in areas remote from the digital television transmitter.
Digital television implies increased signal density. Because of this, serious requirements are placed on the quality of reception. As a result, the antenna equipment must be directed towards the broadcasting “tower”, and if the receiver is located far from the transmitter, it must be amplified in some way.
And if you consider that all Russian regions will switch to digital television in the summer of 2021, then now (in April 2021) it makes no sense to buy a passive antenna for installation outside the city.
