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Progress of signal strength during 24 hours, 18/02/2023


It's been almost 2 years since I checked the signal strength from 28.2°E over a 24 hour period. Then on FreeSport HD. So I wondered how this test would turn out today. Of course, under the same technical conditions, which primarily means using the same satellite receiver. Since I don't have any precise measuring device, the informative value of the performed measurement is not in the absolute value of the signal strength, but in the mutual comparison of the results of individual measurements. The real incentive that made me repeat these measurements was trying to follow snooker matches.

I am a snooker lover. And since Eurosport quite often airs afternoon matches, I turn my dish to 28.2°E, where the BBC's programs are much more generous with this sport. What was my disappointment when I did not manage to catch the program Red Button 1 this year. True, it used to be only in SD resolution, but it "ran" almost without interruptions.

What can be done, progress cannot be stopped. And so the program Red Button 1 was converted to an HD version. With all the negatives that the change in broadcasting parameters brings for our more distant territories. For the sake of completeness, I must add that the original SD version of the program has not completely disappeared. It was just moved to Astra 2F, 12422, H, 27500, 2/3, DVB-S, QPSK, MPEG-2/SD. However, I have a much worse signal from this position than from the original transponder on the Astra 2E. So the "catchability" of the SD version also dropped. And that's why the HD version got clear priority in my investigation of signal strength. I was mainly interested in how this program would be useful for watching afternoon broadcasts in the future.

So I dusted off my still unfinished prototype of the signal strength recording program and applied it to the new parameters of the Red Button 1 HD program. To be sure, I will repeat the measurement methodology. I don't just take one signal strength reading at a given time, I measure the signal strength 10x within 5 seconds and graph the highest reading. This eliminates the short-term signal strength error. The test conditions are as follows:

Jevíčko site, Czech Republic, Latitude: 49.6322°, Longitude: 16.7113°
Laminas 2700 dish, offset
LNB 2x NJR2842
Coaxial cable Belden H125 CU, 45m
Receiver VU+ Duo2, OpenPli 8.2

Broadcast data
 Channel   BBC Red Button 1 HD
 Frequency  10788 MHz
 Polarization  Vertical
 Symbol Rate  23000
 FEC  3/4
 System  DVB-S2
 Modulation  8PSK
 Format  MPEG-4/HD
 Satellite   Astra 2E
 Beam  UK


And now to the measured values. I took measurements 7 days in a row. Each day had slightly different weather, so it might seem that the graphs are not directly comparable. But when I thought about it for a while, it occurred to me that this is not entirely true. Of course, for the objectivity of the measurement, it would be necessary to ensure the same, i.e. "optimal" conditions. But that was not the goal of the experiment. The goal was to verify transponder receptivity. Not only in optimal conditions, but at any time. Therefore, 7 days of measurement is telling in terms of the trend that the signal strength has. Regardless of the current state of the weather, which is beyond our control. And here are the detected data processed into graphs.


Chart 1 - 18/2/2023 ÷ 19/2/2023


Chart 2 - 19/2/2023 ÷ 20/2/2023


Chart 3 - 20/2/2023 ÷ 21/2/2023


Chart 4 - 21/2/2023 ÷ 22/2/2023


Chart 5 - 22/2/2023 ÷ 23/2/2023


Chart 6 - 23/2/2023 ÷ 24/2/2023



Chart 7 - 24/2/2023 ÷ 25/2/2023

The good news is that in the afternoons I was most interested in, the signal was good enough to receive the program. The bad news is that my equipment needs a signal strength of at least 9.2dB for a flawless picture. So the conditions are more or less at the limit of acceptability. Just 1 db extra would give me a usable signal over a much longer time zone. The question is what could be done about it. But that's another story for a completely different article.  


Screenshot 1

I am adding two more Screenshots to the graphs. Both are dated 2/27/2023. On the first one, the signal strength is 9.24 dB at 16:10. On the second, the signal strength is 9.34 dB at 16:53. In both cases, as you can see, the picture is flawless. The OpenWebIf program has a bit of a problem, which when capturing a moving interlaced image shifts the odd and even lines so that the jagged edges of the edges are visible. But that's not the broadcast's fault. The picture on the TV screen is flawless.  


Screenshot 2

Finally, one more piece of information. The data was measured at an interval of 1x per minute. But on the graphs the time scale is after 15 minutes. I don't expect to be interested in more detailed data. But if someone really wants, I can send the complete data in a text file or as an excel table. Just write me an e-mail This email address is being protected from spambots. You need JavaScript enabled to view it. 

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