Why did the TV signal after the antenna amplifier become even worse? Digital TV doesn't work well. The TV does not show from the antenna: what to do

The TV shows poorly from the antenna - there are two reasons. Inconsistency of devices, bad equipment. The latter concerns the antenna; television receivers cope with the tasks one way or another. However, the problem lies in the amplifier. Should at least be configured to the desired frequency. Below we will consider typical situations and methods of solving using the simplest methods. The simple way is to buy a satellite dish and install it. Alternatively, stop watching TV, the Internet is much more fun!

Cable problems

It sounds funny, but the first thing you should do is check the cable. There are several requirements that must be met:

Firstly, characteristic impedance TV cable is 75 ohms. Deviations in magnitude provoke reflection of part of the power in the path, which will inevitably lead to losses. Coordination methods have been invented, using which it is possible to use a cable of a different impedance. Let's wait to fence the garden. Devices designed to operate television broadcasting, characteristic impedance 75 Ohm. We take into account the elementary truth when selecting a cable.

The second tip concerns owners of indoor antennas. A typical picture: a wave channel and a half-wave vibrator with antennae are hanging, and a cable coil lies nearby. First of all, we look at whether the antenna is active or passive. Do you need to turn on the power? If it turns out to be passive, cut off the excess cable and decorate the pantry with a coil. The feeder segment introduces irreparable signal losses. In an antenna receiver, sensitivity strongly depends on the attenuation before the first amplification stage. In our case, it is located inside the TV; the cable to the socket introduces incredible losses. Another thing is the active antenna. The first amplifier stage is located here, the cable length becomes uncritical.
If the passive antenna is on the roof, it’s a good idea to get hold of the cable characteristics using the Internet. It is logical to see whether the linear losses exceed 0.2 dB. The attenuation is determined by the length of the feeder, electrical characteristics products. Three meters of usable cable introduces attenuation, equal to a meter cheap. It is recommended to install an amplification antenna and replace the cable. Fortunately, television is inexpensive. Forget the high cost of high-frequency WiFi!

Why do you need an active antenna?

They said that if the antenna is active, the cable length is acceptable, losses should not be considered a critical element. If you cannot get a good wire, the length cannot be reduced, the roof is far away, you need to buy an active antenna. Please note: to install the equipment, you will need permission from the HOA, the owner of the house. There is insanity: they are forced to draw up a special plan for the placement of utilities, pay a fee to a specialized company, and pay a professional technician to carry out the installation. It has to be done according to the rules.

An antenna amplifier will allow you to bypass the limitations imposed on quality and cable length. The power cord will often need to be pulled to the roof. The distance to the TV station is small, the point is simply blocked by houses - we recommend trying to catch the signal using the indoor variety. The TV will show without a common antenna. It is allowed to place the “Cheburashka”, decorating the balcony, even above the suspended ceiling. The path of passage of the reflected beam is mysterious. However, conditions change according to the weather, and reception will deteriorate (or improve). It is recommended to give preference to omnidirectional antennas, which have a lower directivity coefficient and are equipped with an additional external amplifier.

The antennas reveal a significant drawback that has nothing to do with the quality of reception of an individual signal. The sources of the problems are attributed to the multipath effect. An omnidirectional antenna receives from all directions (azimuths). Several rays will hit, the image will begin to double. Over-amplification causes a similar effect. Remove power electric shock, look at the result. Reddish snow is removed in the same way. The reason is the same - over-amplification.

Advice! Adjust the equipment in an attempt to obtain required characteristics. Reduce gain. Buy a television attenuator. These will reduce the gain by twenty dB.

An undeniable disadvantage of omnidirectional antennas has been noted: interference sources will act from all directions, sharply reducing the signal-to-noise ratio. This is not critical for digital multiplexes; broadcasting contains error correction codes. Reception analogue television with an antenna with an amplifier is impossible if the noise intensifies above the level of the useful component.

Antenna selection and installation

The antenna itself may not match the received signal, or it may not be installed correctly. Many people know that it is useful to orient a device in space, but not everyone knows how to do it. Television in Russia on UHF is built on horizontal polarization, so misalignment of the half-wave vibrator or wave channel is guaranteed to lead to poor reception. At the same time it also shifts frequency range, due to which the picture quality further decreases.

You will need to use a level to align the antenna in the correct position. In addition, when receiving from distant TV towers, a simple rule applies. The higher the antenna is positioned, the greater the chances of catching the broadcast. This rule applies to UHF, which is why the MF and HF ranges still remain attractive. Waves at these frequencies bend around the surface of the earth, so you can catch them without even taking the antenna to the roof.

External barriers also contribute; if there is a forest around, the reception will be worse. Waves attenuate when passing through obstacles. In this case, it is recommended to purchase an antenna with an amplifier. The type also plays a role. Full-wave vibrators receive signals much better, but they are difficult to get in a store. Will help homemade antenna. Made from a copper or aluminum cable core and installed according to the rules, it will provide best reception than store-bought.

We have already told you more than once how to make a narrow-band antenna that is tuned to the channel frequency. In this case, it is also possible to achieve excellent results in simple ways. Eventually, hobbyists are even constructing quarter-wave vibrators for digital receivers. It's just a short piece of wire with a quarter wavelength of shield stripped off at one end. For the first multiplex in Moscow, this is 13.5 cm. A connector is soldered to the other end, which is inserted into the receiver. The quarter-wave vibrator is located horizontally. If necessary, it can be bent at the base for convenient placement. Even such a simple and uncoordinated design produces results in television reception.

Wave channel antenna matching

Beginners are concerned about the question of how to properly match wave channel antennas. The designs are very simple and provide excellent gain. The design is ideal for the UHF, where they lie digital multiplexes. First, let's look at signal balancing. Operation will be required if the descent cable is longer than 10 meters. The device is a piece of wire parallel to the feeder, spaced 3–5 cm.

The method is suitable for a wave channel manufactured according to standard rules. The screen of the reduction cable is simply placed on one side of the active vibrator, but on the other side the balancing section of the cable is attached. The length depends on the channel, for example, for the first Moscow multiplex it is 17.6 cm. At its full length, the piece is parallel to the descent cable. How to connect the device:

The core of the balun is placed on one side of the active vibrator parallel to the core of the reduction cable. The braid of the segment is closed here.
At a distance of the length of the balun from the active vibrator, the insulation of the reduction cable is stripped. The screens of the parallel wires are closed, and the second end of the segment core is connected here.

The situation is much more complicated with antennas whose characteristic impedance is below 75 Ohms. Then special matching devices are used. The active vibrator can be made T-shaped. Upper part The loops are extended with additional wire in both directions. The total length is calculated by the formula:

L = (λ/2)*(1 – 0.225/ln(λ/2d)), where

λ – wavelength, m; d is the diameter of the wire, expressed in meters. The height of the loop is equal to one hundredth of λ or slightly less. The width of the loop is selected experimentally, trying to bring the wave impedance closer to 75 Ohms. The dependence graph is “humpbacked”. The maximum is observed at a loop width equal to λ/4.

By designing your own antenna, this method is suitable for the vast majority of radio amateurs and will allow you to produce a device that has the required impedance. Having a drawing in hand, duplicate the design a specified number of times. Be prepared to work hard if your TV shows poorly. Find out the broadcast frequency and make a special antenna.

Signal interference will be minimal in this case. Construction procedure wave channels described. Explore the portal! Let's gather our strength, consider the design of log-periodic antennas, I'm just curious how to do it. The peculiarity of the product is that it catches a wide range of broadcasts. The coverage of the log periodic antenna is amazing.

To watch television in the country or in small towns, a television or satellite antenna is usually used. Satellite allows you to view large number channels in digital and HD quality, and regular television channels receive terrestrial digital TV. As a rule, these are 20 digital channels.

But sometimes it happens that the signal is interrupted, the image is distorted and there is noise on the screen. This can be caused by various reasons:

problems of broadcasting itself;
problems with receiving equipment;
weak signal.

In the latter case, you can try your TV antenna. However, remember that such actions also increase noise and interference. Therefore, you can first try to improve the signal by reducing losses.

Varieties

Satellite dishes, also called dishes, vary in diameter. The larger it is, the better quality reception. A converter is installed on the plate itself, transmitting the signal to the receiver. There are also signal amplifiers.

Types of satellite antennas:

Television antennas are:

Indoor and outdoor depending on the installation location. Indoor rooms are only suitable for zones confident reception and in the absence of significant obstacles in the signal path.
Active and passive. In the first case it is used active amplifier signal connected to the electrical network.
Based on the range of received waves, all-wave, meter (MV) and decimeter (UHF) are distinguished. Digital broadcasting in Russia it is carried out at UHF frequencies, so a UHF antenna is sufficient.

The quality of the TV signal is influenced by the following factors:

distance from the broadcast tower;
design and material;
active or passive amplification;
connection losses.

Reducing losses

To improve the signal from a television or satellite antenna, you can try to reduce losses in the system:

Signal Boost

You can boost your TV signal as follows:

In the case of a room, place it as close to the window as possible and preferably higher. Make sure there are no obstacles in the signal path.
Raise the external antenna on the roof or higher on the facade so that reception is not hampered by buildings or terrain.
Point the external antenna correctly. This recommendation is also relevant for a satellite dish. Often problems with the signal are simply due to its incorrect location.
You can try to expand the antenna with a piece of wire.
Create a common-mode array design from several identical antennas, placing them horizontally and vertically so that the signal phases in them are the same.
Replace the antenna with a more suitable design and type.
Install a signal amplifier.

To decide how to boost the signal, use simple rule: if the tower is less than 30 kilometers away, then any external passive antenna will do. If the signal is poor, then the problem is within the system, in the equipment, connections or improper installation. If the repeater is more than 30 km away, then use an active amplifier:

The further the distance, the more gain you will need.
Choose one with the lowest noise figure, or rather, it is better to pay attention to the gain/noise ratio.
Pay attention to the voltage of the device. If you increase it, you can increase the gain.

In the same way, you can strengthen the signal of a satellite dish. There are also combined amplifiers that work both on non-television broadcast and on satellite dish. If you are familiar with the theory and practice of radio electronics, then you can assemble an amplifier for a satellite or television antenna with your own hands; there are many diagrams for this on the Internet and in special manuals.

Install the amplifier as close to the antenna as possible. But remember that if you install it outside the room, it will not last long, most likely no more than a year. Due to unfavorable weather conditions, it may oxidize and stop functioning normally.

If your satellite dish previously worked normally and suddenly interference appears, then you can improve the signal with your own hands in the following ways:

Check the serviceability of all elements of the system; perhaps some equipment or part has mechanical damage, is dirty or rusty.
Perhaps the location and direction of the antenna is wrong. In this case, it must be redirected as it was before.
Check if there are any obstacles in the signal path. This could be stuck snow, leaves, branches of an overgrown tree, or a new tall building.

If you initially have problems with image quality, replace the plate with one with a larger diameter. Consult your TV operator for compatible equipment and proper installation.

Thus, most methods and recommendations are universal and can improve the signal of both satellite and television antennas. In case satellite television such a concept as distance to the broadcast source is not used, but the correct directionality, diameter and absence of obstacles are decisive. You can buy an amplifier or make one yourself, but do not forget that it itself is a source of noise and interference. And it is advisable to minimize the use of such devices. Share your experience in the comments if you have encountered problems with signal reception in suburban areas, how and by what means you were able to improve the quality of television reception.

Each of us wants the picture on the TV screen to always be only the most high quality. But, alas, no one is immune from unforeseen situations - sometimes ripples and noise appear, or even the image disappears altogether. One of the reasons for such situations is very banal: the TV has stopped seeing the antenna and refuses to work without its participation. Why does this happen? And who is to blame: TV, cable, antenna? The latter is also a very vulnerable link - some problems and their diagnosis should be further understood.

The TV does not want to please you with a good picture? An extremely common option is breaking the cable itself. Pets, repair work, accidental mechanical impacts - there can be many reasons for this. And if this is really the case, then it will be easy to detect and fix the problem: the TV will be able to receive a signal from another indoor antenna, which will also become a kind of tester.

If the TV cannot receive a single channel from the antenna, another possible reason may become incorrect setting frequency and its definition. You can also find information on how to change settings in the instructions included with the device. conventional antenna, for example, for cable TV. This is not difficult to do - you can do it on your own.

It is not uncommon for the antenna cable to function normally, but the TV still does not receive signals. In this case, the problem may be hidden in the antenna socket, which sometimes simply breaks due to careless handling or for a number of other reasons. You cannot solve this problem on your own - you should contact a highly qualified specialist.

Sometimes the tuner that connects the antenna cable and the TV receiver also fails. And this should also be a reason to contact special services.

It must also be remembered that in some cases it is very negative external antennas Various natural disasters can affect the situation, namely hail, snow, heavy rain, as well as increased cloudiness, strong winds and thunderstorms.

By the way, the reason that the TV temporarily stopped showing may not even be a breakdown, but the ongoing maintenance work. Is it so easy to find out by calling the organization that is responsible for servicing the antennas in the house. You can find out her phone number by examining the receipt for payment for services.

So, if the antenna does not pick up at all, you can take a number of simple steps that in some cases will help quickly correct the situation:

check whether the receiving and transmitting elements are correctly located and in good working order;
find out if the cable is working;
check the functionality of all connections (plugs, antenna sockets, splitter, adapter, etc.)

If you cannot determine the breakdown yourself, it is better not to continue to engage in “self-medication”, but to call a specialist who has experience in this field and can quickly fix the breakdown. Name everything necessary tools and sufficient experience, he will quickly solve all problems, returning a high-quality picture to the TV screen.

Digital television is a modern alternative to standard TV. With this technology, image quality becomes significantly better at the same cost. The essence of this technology is that the signals are a sequence digital combinations electrical impulses. Digital technologies provide new opportunities for transmitting and receiving data.

It has its advantages. For example, mobility. There is no need to stretch wires and cables anymore, all you need is a TV, an antenna, digital receiver and a socket. This is an autonomous system that you can take with you, for example, to the country and watch TV programs with the same quality signal as in the city. In addition, digital TV has a large number of broadcasts, and you can also access the Internet, TV guide, etc.

Possible causes of interference

A digital signal is generally reliable and much better than an analog signal, but even it is not immune to various types of interference. In any case, if the quality of the broadcast deteriorates, you will have to find out the reason why this happened. For example, if the TV does not show well and they are on, you need to check the antenna. Maybe it was installed poorly or just went wrong. The antenna can also break due to a large snowball or piece of ice. In addition, the TV may not show well due to a broken or faulty receiver, etc.

If, when connecting digital TV, the craftsmen fed the cable into the apartment, and further wiring was done independently (especially if there is more than one TV), then perhaps there is a bad tee. Interference may also occur if there is also a computer nearby and they are connected via HDMI cable. As a rule, interference on TV begins when the computer is turned on, and as soon as the computer is turned off, the image becomes high-quality again. In this case, interference may occur due to the computer (or rather, a video card with an HDMI port).

If you live on the top floor and the signal is weak, the nuts on the dividers may have oxidized or burned, the equipment has not been configured, or the optical receiver has failed. There can be many reasons for interference, and the easiest way would be to call a specialist to find it. the real reason and eliminated her.

Availability at your home digital television makes it possible to view a range of different digital television programs. Digital TV is delivered to the consumer by connecting to the appropriate cable television. In this case, you can continue watching the same way analog channels in full.

Instructions

You should know that to take digital signal you need to install equipment that has the function of receiving and playing on the TV screen the standards of the transmitted signal.

These may be the following devices.
Cable receiver, free-standing, DVB-C standard(when using cable networks) or DVB-T (when using regular broadcasting), having a separate control panel. The receiver should connect to the audio-video inputs of almost any TV, both analog and digital;
Modern TV, which has a built-in DVB-C and/or DVB-T tuner. IN in this case just a cable through which you receive the network signal to the antenna socket, and you can receive the signal after setting up the TV.
A computer, however, is required to view this additional availability PC card or external tuner connected via USB port.

If the message “No signal” appears on your TV screen. The image is constantly interrupted. that's most likely the reason. insufficient signal from the antenna. Most common cause Oddly enough, it is a bad contact. in the antenna plug. . Therefore, it is worth checking first. connecting the plug to the antenna cable. Sometimes even just moving the antenna cable is enough. and see how it is reflected in the image. But it is better, of course, to disassemble the plug and visually check how reliable the contacts inside it are. A. the central core does not short to the braid.

Second most popular reason low signal is a failure antenna cable. Even a fairly new cable can. bad to miss television signal because of low quality manufacturing or bends as a result of installation. And even good, well-laid cables over time can lose their ability to conduct a television signal well.

It is worth recalling that digital dvb t-2 broadcasting in Russia broadcasts exclusively in the UHF range, that is, at fairly high frequencies. more high frequencies present. increased requirements for contacts. quality of cable and connections. Therefore, if your antenna begins to show certain channels poorly, then most likely you have problems with reception in the decimeter range. This means that it is unlikely that you will be able to achieve stable reception of digital TV channels until you resolve the issue of proper UHF reception with your terrestrial antenna.

All the problems described above can apply to both active and passive antennas. But there are a number of other problems that may arise when using active antennas. By the way, driving through any Russian populated area, you can meet terrestrial antennas, aimed at the most different sides Sveta. Therefore, it is a good idea to make sure that your antenna is facing in the right direction.

Problems with active antennas

An active antenna differs from a passive one in the presence of two additional elements. the main element is the amplifier, which is located inside the antenna and, despite relative sealing, is often destroyed. exposure to an aggressive external environment. The main enemy. active antennas are lightning strikes and high humidity. The second important element of an active antenna is the power supply. Typically located next to the TV. and is powered from a 220 volt outlet. The power supply has an injector plug that plugs into the antenna input of the TV. His task. transmit power for the antenna through the cable and at the same time do not pass voltage to the antenna input of the TV. The antenna amplifier and power injector are devices that have a limited service life. therefore we recommend. due to the need to use active antennas. and if their use is justified, perform diagnostics of electronic elements.