DSTV loses pic in the rain?

The issue is always a trade off between doing things properly, once and never be bothered again, or, go the el-cheapo route with the lowest possible cost and have to continually replace. Never sure what people are prepared to do so I always leave the choice up to them.

My own antenna is the original 1.2 m antenna, still in perfect condition, well protected from weathering, rust , water collection and properly earthed, installed round about 1999.
The LNB is a 8-way Universal (Octo) LNB capable of receiving hi- and lo- band signals across the complete Ku-band (not only the portion of the band used over Africa).

MC can throw anything at me and it will continue to work.

I have available the facilities to check out all the older decoders, and still have working a DSD 660, 1110, 1131, 1132, SD PVR, UEC HD PVR 4 tuner, Pace HD PVR 4 tuner, and the two models of the HD PVR 2tuners. Most of these decoders are "MC declared faulty decoders" people gave me when they got their new decoders. Very rarely has a decoder been faulty.

I have similarly gathered a collection of MS's and Explora Switches also "declared faulty" by installers.

I have drawn the line at the Explora and the new single view HD decoder. Very happy with the SD PVR - UEC HD PVR 4 tuner combination we use in the home.

MC have declared both these decoders obsolete, no more sw updates etc. But until they stop transmitting signals these decoders can receive, I have no intention of doing anything. The only decoders I have ever bought are the DSD 660, the SD PVR and the Pace HD PVR 4 tuner. The rest are all "faulty decoders" others have dumped.
 
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Ah, the good old days........I remember getting one of the first tvs with the corded remote. Neighbours flocked over to watch this modern marvel. I slumped accordingly in the original Lazy Boy with a real smug smile.
And who can forget the Enlarging screen that you balanced in front of your tiny TV ? Wow, wife and I balanced on the couch and had to sit dead still to watch the SABC logo in focus.
 
daniellgr said:
The TOPTV satellite is much better located for signal reception over SA, with a much improved look angle above the horizon. Hence less affected by rain fades and other atmospheric effects.
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The difference in elevation is hardly going to make a difference in rain fade. If IS20 elevation was like 10 degrees, I would have agreed with you, but the attenuation graph would have already flattened out by the time it reaches 24 degrees. There would not be that much of a difference in attenuation between 24 and 47 degrees (Cape Town elevations) Saying it is much better located is simply not true. Slightly better, well... yes.
 
Quantum Theory said:
The difference in elevation is hardly going to make a difference in rain fade. If IS20 elevation was like 10 degrees, I would have agreed with you, but the attenuation graph would have already flattened out by the time it reaches 24 degrees. There would not be that much of a difference in attenuation between 24 and 47 degrees (Cape Town elevations) Saying it is much better located is simply not true. Slightly better, well... yes.
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I will calculate the path lengths between the two satellites from CT and JHB. Then we can see what the difference in path losses is between the two. But this is not the only issue at hand. It is also to do with the length of the path through the atmosphere differences, and the nature of the weather and typical rain conditions experienced between the two.

Rain not only attenuates the signal. It also causes cross polar conversion and a number of other things which show up as added atmospheric noise, and distortions.
 
daniellgr said:
I will calculate the path lengths between the two satellites from CT and JHB. Then we can see what the difference in path losses is between the two. But this is not the only issue at hand. It is also to do with the length of the path through the atmosphere differences, and the nature of the weather and typical rain conditions experienced between the two.

Rain not only attenuates the signal. It also causes cross polar conversion and a number of other things which show up as added atmospheric noise, and distortions.
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Then there is also the quality that DStv/OVHD broadcasts at from IS20. It is better than what StarSat/OVHD broadcast at from SES5. In clear skies, if I have an 80cm dish on IS20 and measure a DVB-S2 DStv signal with a 30000SR, I will get a much better noise margin and BER than and equivalent StarSat signal, if I turn the same dish to SES5... Bottom line. A perfectly aligned 80cm dish on IS20, should not lose signal unless there is a severe storm, otherwise something is wrong with your installation.
 
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Ok guys, that's flying way over my head.....I'll just report back when the LNB is replaced to avoid looking too stupid.:)
 
dunkyd said:
Ok guys, that's flying way over my head.....I'll just report back when the LNB is replaced to avoid looking too stupid.:)
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Not at all, you offered an opportunity for an interesting debate! Let us know what you decide about fixing the LNB and making sure the antenna is properly pointed.

It sounds like Rocket Science but it is really all about being able to add 1 + 1.
 
Quantum Theory said:
Then there is also the quality that DStv/OVHD broadcasts at from IS20. It is better than what StarSat/OVHD broadcast at from SES5. In clear skies, if I have an 80cm dish on IS20 and measure a DVB-S2 DStv signal with a 30000SR, I will get a much better noise margin and BER than and equivalent StarSat signal, if I turn the same dish to SES5... Bottom line. A perfectly aligned 80cm dish on IS20, should not lose signal unless there is a severe storm, otherwise something is wrong with your installation.
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I have not compared performance between SES5 and IS 20 recently. StarSat is only available on SES5, but OVHD is available on both. How does the comparison between the two satellites look for OVHD? Unfortunately, there are many issues making such comparison difficult to quantify.

As to the path length matter. For CT, the path lengths from CT to SES 5 is 37205.72 Km and to IS20 it is 39 137.56 km. The path losses are 205.4 and 205.9 dB respectively. So all things being equal, under clear sky conditions the performance with a properly aligned antenna should be virtually the same. So the differences in performance you are measuring are due to other factors.
 
Yes. Just wish it could be printed somehow. I'd give it to the company as a manual to help train staff...and so help others.
 
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