Hi everyone,I’m running into some issues with my TV signal and wanted to get advice from people who might have more experience with this.Lately, I’ve been noticing that some channels randomly lose signal or become pixelated, even though the connection seemed stable before. In some cases, the signal comes back on its own, but other times I have to restart the device or re-scan channels. I’m not sure if this is related to the antenna setup, cable quality, receiver settings, or something else entirely.
Here are my details:TV/Receiver Model: Samsung UE43AU7100
Antenna Type: Outdoor antenna
Connection Type: Coaxial cable (RF)
I’ve already tried:Repositioning the antenna
Checking cable connections
Re-scanning channels
But the issue still happens occasionally.Recently, when the signal gets unstable, I’ve also been relying on streaming as a backup (since live TV becomes unwatchable at times). I noticed some people even mention using apps like YouTube Premium APK (ytmodz) for smoother ad-free streaming experiences, but I’m not sure if my issue is actually signal-related or something on the network/streaming side overlapping with it.
Has anyone here faced similar problems where broadcast signal issues and streaming performance seem to mix or confuse the diagnosis?What would you recommend checking first in my case—antenna alignment, cable shielding, or possibly the TV tuner itself?Any help or suggestions would really be appreciated.
Google translator: Mam problemy z sygnałem telewizyjnym i chciałem uzyskać porady od osób, które mogą mieć większe doświadczenie w tej kwestii.
Ostatnio zauważyłem, że niektóre kanały losowo tracą sygnał lub stają się pikselowane, mimo że połączenie wcześniej wydawało się stabilne. W niektórych przypadkach sygnał wraca sam, ale innym razem muszę ponownie uruchomić urządzenie lub przeszukać kanały. Nie jestem pewien, czy jest to związane z ustawieniem anteny, jakością kabla, ustawieniami odbiornika, czy czymś zupełnie innym.
Oto moje szczegóły:
Model TV/Odbiornika: Samsung UE43AU7100
Typ anteny: Antena zewnętrzna
Rodzaj połączenia: Kabel koncentryczny (RF)
Próbowałem już:
Zmienić położenie anteny
Sprawdzić połączenia kablowe
Ponownie przeskanować kanały
Ale problem nadal zdarza się od czasu do czasu.
Czy ktoś z Was spotkał się z podobnymi problemami? Co byście polecili sprawdzić lub dostosować w pierwszej kolejności? Czy może to być problem z siłą sygnału, czy bardziej prawdopodobna jest awaria sprzętu?
Każda pomoc lub sugestia będzie naprawdę cenna."
The answer is not simple.
It is the typical worldwide problem after start DVB-T2 broadcasting.
The most fast method to resolve it, is call the expirienced TV-antenna fitter, who has special measurment equipment >>(for example ROVER EXA - 7)
https://www.roverinstruments.com/product/exa-7/
It is difficult to explane, how to resolve problem, without basic knowledge about DVB-T2 & TV antennas. But we try to give You a few practical tips and advice. But, the first We must write them in polish lenguage and then drop them on google translator.
By the way, technical english, is not wery popular beetwin older but expierienced, Polish entusiasts of resolving TV-antennas problems.
Currently, it's important to remember to block signals from 5G LTE 700, 800, and 900MHz BTS transmitters reaching the TV receiver through the TV receiving antenna using low-pass filtering. For example, using the Terra TF-005 filter
https://www.bing.com/search?q=5G+LTE+700+block+FILTER
Echo interference problems in the SFN system
For example, in town A, signals from mux1 on channel 43 and mux2 on channel 23 reach the receiver – both from Transmission Center 1 at site B (33km away) and from Transmission Center 2 at site C (52km away). Additionally, signals from both Broadcasting Centers may undergo refraction, reflection, and scattering along their way to the receiving antenna, and then overlap and interfere again, with varying time delays and carrier intensity levels, resulting in multipath transmission to the receiving antenna. These phenomena can cause difficulties in correctly decoding the DVB-T2 signal. Theoretically, the same signal from location B reaches the receiving antenna (subscriber) in location A at the speed of light in the Earth's atmosphere, slightly delayed compared to the signal from location C (a distance difference of 19 km), i.e., by approximately 0.00006333 seconds (6.3 hundred-thousandths of a second).
This is very short, but digital processing of a DVB-T2 television signal—that is, first encoding it for transmission at the Broadcasting Center and then decoding it after reception by the receiving antenna—takes (additionally) significantly longer, at least 1 to 2 seconds. The same signal, for example, transmitted from a television studio to a satellite in stationary orbit and then to any terrestrial DVB-T2 broadcasting center, can reach not only directly but also via terrestrial radio links or fiber optics. Along the way, it may undergo additional signal processing with an additional time delay, often different for each broadcasting center.
In total, the time differences between watching the same television program received from two different RTCNs could amount to up to several seconds.
When broadcasting the same signal in the Single Frequency Net system, on the same frequency by "neighboring" broadcasting centers, time synchronization is likely applied by additionally delaying the "faster" signal. This is intended to allow a relatively inexpensive DVB-T2 decoder at the subscriber to compare the same signals reaching the receiving antenna and select the best-quality signal for playback on screen.
Because the signal propagation conditions—in the near-ground "aether" and the formation of reflections (the carrier waves of which can either add or subtract)—change for various reasons, the decoder has the ability to switch to a better-quality signal. The more efficient, faster, and intelligent the decoder, the less noticeable interference during signal changes should be on the TV screen. The ability of a decoder to operate smoothly in an SFN network depends to some extent on the difference in the strength of the signals being compared and their mutual delay.
In certain specific cases, different types of decoders and TVs may (for better or worse) >>NOT COPE<< with this problem.
Indeed, some users report that some DVB-T2 decoders and DVB-T2 TV receivers cope better with such interference in SFN networks, as well as with echo interference, while others do not.
Some praktical notices:
The inquirer (in Poland) can always visit the websites with the coverage maps of the DVB-T2 transmitters and, after manually enlarging the maps, carefully read the forecast of the algorithm that calculates the electromagnetic field strength of the DVB-T/T2 signal at the receiving location, taking into account the influence of the surrounding terrain. The algorithm generally does not take into account the degree of forest cover and buildings, which, by blocking the signal, can reduce the expected field strength (signal).
It's worth remembering that the range (or rather, the forecast of the electromagnetic field strength of the useful signal) is calculated theoretically, not through actual field measurements, and assumes that the receiving UHF antenna, without a preamplifier, is suspended 10 meters above ground level and has an energy gain of 10 dBd (i.e., relative to the gain of a half-wave dipole) or an energy gain of ~12.15 dBi (i.e., relative to the energy gain of an isotropic antenna).
The electromagnetic field strength forecast for a given area is expected to be accurate in 50% of locations. For example, due to the interaction of the signal arriving directly from the RTCN transmitter with its reflections, the actual signal level may, as a result, differ significantly from the forecast.
After the introduction of digital terrestrial television broadcasting, the ability to assess reception quality and antenna signal quality based solely on the "appearance" of the image on the television screen (compared to analog television reception) has significantly decreased.
Therefore, it is useful to check, in such locations, the actual DVB-T/T2 signal level and any potential interference using a dedicated antenna and an appropriate antenna signal quality meter: MER, BER, C/N, the presence of EXTERNAL signal echoes, and the spectrum of adjacent frequencies for the VHF and UHF bands.
Providing the exact reception location—a screenshot of a map (or even the location of the receiving antenna relative to the building)—significantly simplifies answering questions on the forum. Photos of the current antenna's condition also make it easier to assess the feasibility of resolving reception issues and provide advice based on existing conditions if the person making the changes themselves is aware of the situation. But it's clear that not all inquirers desire such confidential disclosure.
Problems with good DVB-T2 signal reception near a powerful DVB-T2 Broadcasting Center.
The greatest power from DVB-T2 transmitters is radiated in a plane tangent to the horizon of the optical range of these antennas. However, the closer to the Broadcasting Center mast, the lower the power of DVB-T2 signals radiated toward the ground from the vertical array of UHF antennas. In theory, the lower the power, and in practice, the lower the power of DVB-T2 signals radiated toward the ground from the vertical array of UHF antennas. For example, by selecting the phase angle for individual UHF antennas in the vertical array.
This is further compounded by the interference of waves directly reaching the subscriber's receiving antenna with waves reflected from the ground, roofs, and walls of buildings between the UHF transmitting antennas on the Broadcasting Center mast and the subscriber's receiving antenna. For example, zones of significantly reduced or increased electromagnetic wave intensity can be created, resulting from the subtraction or addition of the direct wave and the reflected wave, which is appropriately phase-delayed relative to the direct wave.
The majority of such zones can occur at distances of 0 to 10 km from the Transmission Center mast. Nevertheless, signal intensity levels in the zones where the main wave and the reflected wave subtract can actually be high enough to ensure DVB-T2 reception.
However, there is also the potential problem of high levels of external echo interference, which, even in a Single Frequency Net configuration, can prevent reception of some multiplexes. In this case, a small, single Yagi-Uda antenna with relatively LOW DIRECTIONAL properties has a lower chance of ensuring uninterrupted DVB-T2 reception. Even though the signal levels fed to the RF tuner input of a TV or set-top box will be sufficient or even too high, the signal levels themselves will be sufficient or even too high. Without a professional antenna meter capable of measuring signal levels and observing the signal spectrum and echo signals, it can be difficult to quickly determine the cause of a complete lack of reception on a specific MUX, or only occasional poor reception.
In the higher UHF frequency range (470MHz-694MHz), used for DVB-T2 (HEVC) digital terrestrial television broadcasting, i.e., on channels 21-48, TV band IV and V, the intensity of electromagnetic waves (so-called industrial interference) is significantly LOWER than in TV band III (174-230MHz). And even if they do occur, they have a shorter range and are more strongly attenuated in the space where they reach (our individual subscriber TV antennas) DVB-T2 signals. For this reason, among other reasons, some discussions have also raised the idea of abandoning the TV band III in favor of distributing DVB-T2 digital terrestrial television signals.
Because higher-frequency electromagnetic waves carrying DVB-T signals are more strongly attenuated in antenna cables (as high-frequency currents induced in the receiving antenna) and in space (the so-called ether) as electromagnetic waves, their reception requires the use of more sophisticated receiving antennas with higher energy gain than in the TV band III, i.e., channels 5-12.
For a similar reason, the effective radiated power (ERP) used for broadcasting DVB-T2 programs on UHF channels 21-48 is at least 10 times higher than in the TV band III, channels 6-12.
Yagi-Uda antennas extended longitudinally (to achieve a higher energy gain G) - thanks to this extension, they have better DIRECTIONAL properties and - a higher front/back radiation RATIO (F/R, F/B) - achieved by using more extended resonant reflectors or aperiodic mesh reflectors. These receiving antenna parameters additionally (to some extent) allow for limiting the reception, by subscriber antennas, of UNWANTED signals, i.e. signals harmful to interference-free reception of DVB-T2 programs, such as: EXTERNAL ECHOIC reflections from various directions, interference from electrical devices NOT PROTECTED against interference, combustion engines with electric ignition, sparking from the power grid, tram or trolleybus networks, faulty/damaged street lighting, etc.
So-called combined antennas, as a compromise between cost, quality, dimensions, and electrical properties, typically have poorer directional discrimination of unwanted signals due to the close proximity of elements with resonant characteristics (different for UHF and UHF), in a spatial configuration that is not always, or rather, too often, poorly chosen. Moreover, they are usually used in a configuration that has not been tested in practice – using field measurements.
Using separate antennas for the UHF and VHF bands, connected by an antenna diplexer, allows for the freedom to independently adjust the antenna orientations to better utilize their directional discrimination properties. >> This is to reduce the reception of echoes, unwanted signals, and other electromagnetic interference reaching the receiving antennas.
The more directional Yagi-Uda antennas are, the longer they must be, and have the greater the energy gain in the main beam of the directional characteristic (receiving and transmitting), and the narrower the main beam (due to the operating principles of Yagi-Uda antennas).
And the higher the price, ofcours.
If the DVB-T2 signal (induced in the receiving subscriber antenna), for example, near a broadcasting center, is too high, it can be attenuated with a variable attenuator or a fixed attenuator determined by measurements, tests, and possibly experience.
The antenna's narrow main beam pattern (radiation-reception) and high front/rear radiation ratio (F/R, F/B) allow for the selection of (independent) receiving antenna orientations to minimize (separately and selectively) the levels of unwanted signals at individual antennas. This is further aided by a bandpass antenna diplexer and the possible addition (if necessary) of channel filters. Or even an antenna amplifier, such as a Telmor MAESTRO, which automatically equalizes the levels of usable DVB-T/T2 signals at the amplifier output.
At one time, the replacement of analog terrestrial television with digital terrestrial television (DVB-T) temporarily allowed individual subscriber antenna installations to abandon the use of specialized and more expensive hardware solutions (developed and manufactured long ago). This included significantly expanded dimensions of many types of high-gain receiving antennas with a narrow operating frequency band, in order to achieve greater energy gain, with a narrow main beam (directional radiation (reception) pattern).
Of course, in favor of the use of small, broadband and multi-band combined antennas with less excellent directional discrimination parameters of unwanted signals and poorer WFS (WFB) matching.
For this reason, mass production, as well as the practice of using multi-antenna receiving installations—individual, equipped with narrow-band (or even single-channel), "exhausted," long receiving antennas—has disappeared. Yagi-Uda antennas, antenna diplexers, precision antenna filters, mast-mount channel preamplifiers, channel antenna baluns (i.e., with channel filters).
Probably in the Czech Republic, someone is custom-producing these more sophisticated, long Yagi-Uda antennas and tuned, channel-specific, passive accessories for them, including antenna diplexers and filters;
The transition from DVB-T to DVB-T2 HEVC (with more efficient signal compression, HEVC 265) allowed for an increase in digital data throughput within a single MUX (still occupying a similar frequency band to the former analog single-channel TV frequency channel, which, in the past, transmitted only one analog TV program).
This resulted in INCREASED REQUIREMENTS for DVB-T2 signal QUALITY - fed to the antenna input of the high-frequency tuner of a DVB-T2 television receiver or DVB-T2 decoder (switch):
Signal parameters according to the 60728-1 standard (at the antenna OUTPUT at the Subscriber's)
- (older) DVB-T standard: min. MER 26 dB, S/N (51 dBuV÷74 dBuV) for (FEC 5/6 GI 1/4)
- NEW DVB-T2 standard: min. MER 32 dB, S/N (46 dBuV÷74 dBuV) for (FEC 3/4 GI 19/128),
(48 dBuV÷74 dBuV) for (FEC 4/5 GI 1/8) currently MUX4
The DVB-T2(HEVC) tuner indications in MENU->> SETTINGS->> (CHANNEL SEARCH), on a DVB-T2 TV, or in a DVB-T2(HEVC) set-top box/decoder are approximate. Messages and indications such as:
- no DVB-T2 signal,
- 0% quality,
- jumps in the quality bar,
even with the indicated signal strength of 100%, - (in addition to too low a signal level from the antenna, they can also be caused by various interferences.) Examples include:
- damage to the antenna preamplifier power supply, including: lack of suppression of rectified DC ripple (electrolytic capacitors), damaged stabilization circuit in the antenna preamplifier power supply,
- too high amplification of the useful signal by the preamplifier/antenna amplifier,
- too high a signal level, without an antenna preamplifier but in close proximity to a strong DVB-T2 Broadcasting Center transmitter,
- electromagnetic interference from: spark-ignition motors,
- sparking on the connections of the 230V power supply network (domestic and street).
- and interference from the power supply systems of fluorescent lamps, LED lamps, or other types of street lighting,
- interference from damaged power supplies and switching device converters,
- electromagnetic interference radiated by neighboring receiving subscriber antenna installations, from overloaded antenna signals, resulting from improperly selected, excessively powerful antenna preamplifiers,
AND
- interference from LTE/800MHz and 5G/700MHz wireless communication transmitter networks. In this case, the use of low-pass antenna filters that suppress frequencies above 700MHz is recommended, for example:
https://www.bing.com/search?q=Filtr+LTE+700+TF005+Terra
There is also the problem of interference with DVB-T2 reception, originating from the newly introduced LTE 420MHz telecommunications frequencies.
In Poland, a helpful website with maps of mobile cellular BTS transmitters and 5G and LTE signal emissions is available. 700MHz, 800MHz, 900MHz.
BTSearch:
https://beta.btsearch.pl/ Maps of the location and parameters of BTS stations, i.e., cellular (mobile) wireless communication stations, whose close proximity to an individual (subscriber) DVB-T2 receiving antenna, or their position in the line of sight of DVB-T2 programs from the Broadcasting Center, MAY interfere with the reception of DVB-T2 television programs.
