Background:
This document is about all the problems related to the reception of sky digital in southern Spain, what works, what doesn't and what you have to do to get the most of your installation.
This document is not intended to be a "basic" installation guide, rather covers very deep technical aspects of the digital satellite television. I've read and hear a lot of bullshit about the topic, and wanted to clear up the situation doing the things myself.
Initial Considerations :
I've been a subscriber of Sky since the beginning of 1993, the reason for that was mainly to improve my English speaking skills and to see quality television as well. At that time Sky broadcasted from the Satellite Astra from it's orbital position of 19.2 degrees, to achieve reasonable quality you needed a minimum of 90 cm dish. Then in 1998 the "digital" revolution started, Sky started broadcasting from a new Astra orbital position of 28.2 degrees and had a new footprint centered mainly in England. Due to the problems related to the change my subscription to digital, I took some time to do it, and do so in October 2000. Suddenly when moved the dish I discovered that some of the channels were not receivable or lost it's signal at some times in the day. After seeking for solid information abt the situation, I discovered that no one has written anything abt the topic, so I decide to take some equipment and do some tests
Equipment used to do the test:
Signal meter
and Spectrum Analyzer Promax, prolink 3
2 mtrs prime
focus Precision-Antennas antenna
1.20
mtrs offset Tecatel antenna AL-G135FNZ
SMW LNB's and orthomode
PHILLIPS Universal .7 db LNB C120
Fujitsu digital camera
Personal Computer with custom VB program
Goals of the tests:
The goals
of the tests were the following:
- Understand if it was worth use a 2.0 mtr antenna against a smaller one
- Understand how critical the adjustment is
- Understand how different LNB's perform
- Understand why different channels perform differently during the day
- Understand what is the maximum number of channels receivable
Tks to Jose Gorrita who helped me trough all the ordeal and to Gines to let me the Spectrum Analyzer
Coverage Footprints:
The images on the left are the foot prints of the Astra 2's satellites, copositioned at 28.2 degrees, there are to main groups, first Astra 2A and 2B wich have transponders north and south, both satellites have exactly the same footprint (as claimed by Astra.
Astra 2D is a different animal, the footprint is centered at UK and seems targeted at UK only viewers
First image is Astra 2A / 2B South, second is Astra 2A / 2B North and third is Astra 2D
If you considered that the antenna dimensions that Astra gives are "safe", that meant that wewill be able to pick signals from Both North and South Beams with a 1 mtr dish, and that probably will be no way to get signals from Astra 2D
To get a good understanding that which beams carry which programs have
a look at lyngsat
, which has been a very valuable source of information
First thing was to set up both systems, the place we did the tests was the emitter center of Radio Gandia, of which Gorrita is his technician
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With those coverage footprints you can expect full reception all day
in any transponder on Astra 2A and 2B, and no reception on Astra 2D.
The Eurobird satellite, which is owned by eutelsat, is leased by Astra and carries some Sky channels, but I'm not going to talk about the eurobird here, since it will be replaced by Astra 2C in the near future
Reality is somewhat different, and you don't get what you think, those are the reception figures that you get with 60cm offset, 1.20 mtr, offset and 2.0 mtr prime focus. Those figures assume that you have a good LNB and you have pointed the antenna and adjusted the skew correctly.
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Figures with 60 cm antenna (times
are GMT)
2A South TP's: All day
2B South TP's: All day
2A North TP's: No reception
2B North TP's: From 03:00 to 21:30
2D TP's: No reception
Figures with 1.20 m antenna (times
are GMT)
2A South TP's: All day
2B South TP's: All day
2A North TP's: From 00:00 to 01:00 , from 03:15 to 12:00, from 18:30 to
23:59
2B North TP's: From 02:00 to 22:00
2D TP's: No reception
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2A South transponders: All day
2B South transponders: All day
2A North transponders: From 00:00 to 14:00 , from 17:30 to 23:59
2B North transponders: All day
2D Transponders: From 08:00 to 11:00
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