]]Pointing the Dish[[
To receive a strong and reliable signal in all weathers the dish must be pointed directly at the satellite.
Select a position where the path to the satellite is clear and unobstructed (for example a tree without leaves in winter will cause no problem - but in summer virtually no signals will get through to the dish).
"Pointing the dish" means setting the Azimuth and Elevation correctly.
* Elevation is the angle between horizontal and the satellite in orbit on the Clarke Belt.
(In the UK this ranges from about 21° in the far north of Scotland to about 27° in the south of England [for Astra 1]).
* Azimuth is the position (east or west of south) where the satellite is located (19°E, 1°W, etc).
* Skew (or polarization offset) is the final little tweak required to get the strongest possible signal from the satellite. Instead of having the
LNB fixed vertically in it's holder, a few degrees of clockwise (right) or anticlockwise (left) twist from the vertical is applied to compensate for the position of the satellite being either east or west of due south (in the northern hemisphere). The skew applied in northern UK for Astra-1, 19°E, is 10° clockwise. This increases to 16.5° for viewing Astra-2 at 28°E
]]Satellite Transponders[[
See 'SatTV_Transponder' diagram below.
Transponders are interleaved using opposite polarity
Adjacent transponders are transmitted with alternate polarity. This allows more transponders to be used within the frequency band(s) allocated to satellite DTH broadcasting. The
LNB is capable of switching between signal polarity, ie. Vertical and Horizontal.
Each transponder on a satellite has a typical bandwidth of 27MHz.
A single analogue channel will occupy this whole space. Up to 14 compressed digital TV channels can be fitted into the same space.
Symbol Rate represents the data rate (typically 27500Kbps) - see below.
FEC is the Forward Error Correction factor inserted by the broadcaster. The data stream can include TV, Radio and/or computer data.