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DVB-T Program Reception: Comparing Signal Quality of k54, k37, and k48 Transmitters in Ostrava

makar42 8055 11
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  • #1 16919996
    makar42
    Level 16  
    Posts: 489
    Rate: 70
    Due to my place of residence, I receive Czech DVB-T programs from transmitters in Ostrava. Three multiplexes are available: k54 (738MHz), k37 (602MHz) and k48 (690MHz). I receive the first two with 100% quality, while the quality of the k48 signal ranges from 10-20%. According to the data on www.digitalnitelevize.cz, all 3 transmitters work with 100kW power and the range is illustrated by the attached map (far beyond my home).
    I use a mesh antenna and a multi-band amplifier for reception. I enclose the test results of the ProgFinder program of the above frequencies. Maybe anyone has any suggestions about the causes of this condition?
    Attachments:
    • DVB-T Program Reception: Comparing Signal Quality of k54, k37, and k48 Transmitters in Ostrava zasięg.gif (928.35 KB) You must be logged in to download this attachment.
    • DVB-T Program Reception: Comparing Signal Quality of k54, k37, and k48 Transmitters in Ostrava Level690MHz.jpg (137.7 KB) You must be logged in to download this attachment.
    • DVB-T Program Reception: Comparing Signal Quality of k54, k37, and k48 Transmitters in Ostrava Q602MHz.jpg (117.27 KB) You must be logged in to download this attachment.
    • DVB-T Program Reception: Comparing Signal Quality of k54, k37, and k48 Transmitters in Ostrava Q690MHz.jpg (119.29 KB) You must be logged in to download this attachment.
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  • #2 16920307
    LeDy
    Level 43  
    Posts: 19057
    Help: 1984
    Rate: 2917
    To begin with, replace the power supply with one with regulation. What amplifier in the antenna?
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  • #3 16920438
    makar42
    Level 16  
    Posts: 489
    Rate: 70
    There is only a balancer in the antenna. I am not sure what the regulated power supply (voltage?) Would give. The AWS-1031 antenna amplifier is powered by 12V voltage and has 3 inputs for the 21-60 range, with adjustable output signal level.
  • #4 16920517
    maksar
    Level 34  
    Posts: 2515
    Help: 177
    Rate: 1029
    makar42 wrote:
    There is only a balancer in the antenna. I am not sure what the regulated power supply (voltage?) Would give. The AWS-1031 antenna amplifier is powered by 12V voltage and has 3 inputs for the 21-60 range, with adjustable output signal level.

    Where is this information in the first post that you have to pull your tongue?
  • #5 16920568
    nomudrek
    Level 36  
    Posts: 2241
    Help: 406
    Rate: 469
    On channel 48 (690 Mhz) programs are received but from the second transmitter in Ostrava (Hladnov), which transmits with a power of 10 kW hence the low signal level. Good reception would be, however, from the Ostrava transmitter (Hošťálkovice), whose power is 100 kW. Both transmitters broadcast on the same channel and almost from the same direction, hence the difficulty to pick up from the stronger one.
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  • #6 16920851
    makar42
    Level 16  
    Posts: 489
    Rate: 70
    maxar - "do you have to pull the language?" - what form is that!
    nomudrek - the "Level690MHz" graph gave suspicion of interference from a transmitter of the same frequency. I searched first on the Polish side, but there is no k48 transmitter within 100 km from me. I read about this second Czech transmitter (10 kW) on this page www.digitalnitelevize.cz, but I did not consider this aspect, because why the 10 kW transmitter, located in the center of the city on a tower water reservoir, would disturb 100 kW on the 185 m high tower
    Attachments:
    • DVB-T Program Reception: Comparing Signal Quality of k54, k37, and k48 Transmitters in Ostrava Hladnov.jpg (602.85 KB) You must be logged in to download this attachment.
  • #7 16920991
    maksar
    Level 34  
    Posts: 2515
    Help: 177
    Rate: 1029
    makar42 wrote:
    "do you have to pull the language?" - what is this form

    Read point 3.1.15 of the regulations.
    Maybe some other equipment. Or maybe by hand, as it is possible to search.
    It's all given, not just help!
  • #8 16922300
    LeDy
    Level 43  
    Posts: 19057
    Help: 1984
    Rate: 2917
    makar42 wrote:
    There is only a balancer in the antenna. I am not sure what the regulated power supply (voltage?) Would give. The AWS-1031 antenna amplifier is powered by 12V voltage and has 3 inputs for the 21-60 range, with adjustable output signal level.

    And where did you write what amplifier you have?
    And what do you dislike about "pulling the tongue"? Do you have any associations?
    It's a simple statement that you should give everything in the first post.
  • #9 16926066
    makar42
    Level 16  
    Posts: 489
    Rate: 70
    nomudrek - Your claim about interference from Ostrava k48 transmitters is probably not entirely true. It turns out that the Hladnov water towers also have k54 and k37 transmitters, also with a power of 10kW each, but they do not interfere with 100kW transmitters from Hošťálkovice. (same channels)
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  • #10 16928981
    MICHAŁ
    Level 18  
    Posts: 276
    Help: 15
    Rate: 30
    The reason for this is that you receive mux 1 and mux 2 (Czech) with better quality than mux 3 (Czech) because you probably pick them from Lysa Hora. Transmitters 25 KW but located high over 1300 m hence large range. Mux 3 (Czech) is not broadcast from this location, hence the worse signal.
    https://www.digitalnitelevize.cz/vysilace/region-moravskoslezsky-kraj.html
  • #11 16929893
    makar42
    Level 16  
    Posts: 489
    Rate: 70
    An interesting theory. Transmitters from Łysa Góra did not take into account, because: distance 60 km and power 25kW, when at 30 km I have 100 kW transmitters. By the way, I don't quite understand how it is with digital signal interference - is it or not?
  • #12 16937203
    makar42
    Level 16  
    Posts: 489
    Rate: 70
    I went to dvbtmap.eu and took off the terrain profile for the signal from Łysa Góra and Ostrava and everything is clear. On the route from Ostrava, the KWK Rydułtowy heap is an obstacle. To find out the validity of this thesis, I went to a friend who lived about 2 km west of me - MUX3 receives 100% quality. I am looking forward to the demolition of this heap.
    I'm closing the topic.
    Attachments:
    • DVB-T Program Reception: Comparing Signal Quality of k54, k37, and k48 Transmitters in Ostrava Lysa Gora.png (4.3 KB) You must be logged in to download this attachment.
    • DVB-T Program Reception: Comparing Signal Quality of k54, k37, and k48 Transmitters in Ostrava Ostrawa.png (4.76 KB) You must be logged in to download this attachment.
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Topic summary

✨ The discussion centers on the reception quality of Czech DVB-T programs from transmitters in Ostrava, specifically comparing multiplexes k54, k37, and k48. The user reports receiving k54 and k37 with 100% quality, while k48 fluctuates between 10-20%. Responses suggest potential causes for the poor reception of k48, including interference from a lower power transmitter (10 kW) in Hladnov, which operates on the same frequency. Recommendations include checking the power supply of the AWS-1031 antenna amplifier and considering the geographical obstacles affecting signal reception. The user later identifies that terrain features may obstruct the signal from higher power transmitters, leading to better reception in nearby areas. The discussion concludes with the user confirming the impact of local topography on signal quality.
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FAQ

TL;DR: In Ostrava, co‑channel k48 suffers because Hladnov transmits at 10 kW while Hošťálkovice uses 100 kW; “Both transmitters broadcast on the same channel and almost from the same direction.” [Elektroda, nomudrek, post #16920568] Why it matters: This FAQ helps over‑the‑air viewers diagnose why one DVB‑T multiplex breaks up while others look perfect, and what to try.

Quick Facts

Why is k48 reception weaker than k37 and k54 in Ostrava?

Because two Ostrava sites share k48. Hladnov (10 kW) and Hošťálkovice (100 kW) arrive from nearly the same direction. Their signals can clash, so your tuner locks inconsistently on k48 while k37/k54 remain clean. “Both transmitters broadcast on the same channel and almost from the same direction.” [Elektroda, nomudrek, post #16920568]

Can two same‑channel DVB‑T transmitters cancel each other out?

Yes. Co‑channel signals of similar arrival strength can create self‑interference. When they come from near‑identical bearings, your antenna cannot spatially discriminate, so MER drops and errors rise. As one expert put it, “Both transmitters broadcast on the same channel and almost from the same direction.” [Elektroda, nomudrek, post #16920568]

Could terrain or structures be the real culprit for my Mux 3 issues?

Absolutely. A documented case showed the KWK Rydułtowy spoil heap blocked the Ostrava path. A quick field test 2 km west delivered 100% Mux 3 quality, confirming obstruction. Use terrain profiling to verify your line‑of‑sight. [Elektroda, makar42, post #16937203]

Why are Czech Mux 1 and Mux 2 strong, but Mux 3 is weak or missing?

Mux 1 and Mux 2 can arrive robustly from Lysá hora, which sits around 1300 m. That elevation and takeoff angle extend coverage. Mux 3 is not broadcast from Lysá hora, so you rely on other sites and paths that may be obstructed. [Elektroda, MICHAŁ, post #16928981]

How do I confirm a terrain blockage is causing my reception problem?

Try this: 1. Check the path on a terrain‑profile tool and note obstacles. 2. Test from a nearby location offset by 1–3 km to change the path. 3. Compare Mux quality; a jump to 100% strongly indicates obstruction. [Elektroda, makar42, post #16937203]

Will changing my power supply or gain help DVB‑T stability?

Yes. An adjustable, regulated PSU and proper gain staging prevent overload or under‑drive in mast/indoor amplifiers. If k37/k54 are strong, too much gain can compress the front end and worsen k48. Start by fitting a regulated supply and trimming gain. [Elektroda, LeDy, post #16920307]

Does a higher site with lower ERP beat a nearer, higher‑power site?

It can. Lysá hora’s ~25 kW carries far thanks to its ~1300 m elevation and clear path, often outperforming lower, urban sites for some locations. Elevation and line‑of‑sight can outweigh pure power on UHF. [Elektroda, MICHAŁ, post #16928981]

Could a Polish k48 transmitter be interfering here?

Unlikely in the cited case. The user checked and found no Polish k48 within ~100 km. That points back to Ostrava co‑channel conditions or local terrain as the drivers. [Elektroda, makar42, post #16920851]

What antenna and amplifier setup was used in the thread’s tests?

A mesh antenna with a balun fed an AWS‑1031 multiband amplifier. The amp runs on 12 V, offers three UHF inputs, and has an adjustable output level for balancing muxes. [Elektroda, makar42, post #16920438]

How should I aim the antenna when two Ostrava sites sit on nearly the same bearing?

Fine‑tune azimuth to favor Hošťálkovice on k48 while minimizing Hladnov’s contribution. Small azimuth shifts and antenna pattern nulls can help separate arrivals when bearings are close. Expect iterative tweaks and re‑scans. [Elektroda, nomudrek, post #16920568]

What does “Mux” mean in this discussion?

Here, “Mux 1/2/3” refers to Czech DVB‑T multiplexes—bundles of TV programs carried together on one RF channel. The thread contrasts their sites: Mux 1/2 from Lysá hora, while Mux 3 is not. [Elektroda, MICHAŁ, post #16928981]

What was the final diagnosis and resolution path in the thread?

Terrain was the key factor. A spoil heap blocked the Ostrava path at the original location. Testing 2 km west yielded 100% Mux 3 quality, confirming obstruction and closing the case. [Elektroda, makar42, post #16937203]
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