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Concept
Receive AsiaSat 2 at 100.5oE and AsiaSat 3S at 105.5oE with 1 TVRO dish
Benefits to Broadcasters
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Combined audience penetration of AsiaSat 2 and AsiaSat 3S |
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over 96 million households with more than 360 million viewers across the Asia Pacific |
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Combined channel neighbourhood of AsiaSat 2 and AsiaSat 3S |
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140+ premier television channels |
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multilingual bouquets of South Asian, Middle Eastern, European, Chinese and international Programming |
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Inter-satellite back up |
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service continuity made possible by second feeds installed at receiving sites |
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Benefits to Cable Headends / Receive Sites
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Increase channel offerings through access to multiple broadcast platforms via a single TVRO |
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Expand subscriber base through enriching programming packages |
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Increase revenue through enlarging subscriber base |
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Low implementation cost to expand service packages to subscribers/viewers |
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Allow service continuity with second feeds installed at receiving sites |
How to Retrofit Existing Single Feed TVRO?
Set Up Configuration
Steps
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Retrofit the existing C-band TVRO dish that has a single feed and LNBs pointing to either AsiaSat 2 or AsiaSat 3S |
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Install a secondary feed assembly and LNBs to the existing TVRO dish |
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Connect the IF cable to the additional LNBs |
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Align the secondary feed horn and optimise the additional feed position for best quality signal |
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Rotate the secondary feed to get the right polarisation angle |
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Once obtain the best C/N ratio, fix the LNBs at the selected position |
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Installation of the secondary feed is complete when achieve the maximum signal levels of both satellites |
Details of Aligning the Additional Feedhorn
To receive more than one satellite simultaneously using
one dish antenna, you need to find out two additional
angles to fix the supplementary feedhorn besides the Azimuth
and Elevation angles of the primary satellite. They are the "Relative Separation
Angle" and "Feed Offset Angle".
The relative separation angle is used to align the supplementary
feedhorn on the transversely displaced feed point of the secondary satellite.
Feed offset angle is used to find out the position of
the supplementary feedhorn.
Antenna Alignment
Imagine that there are two planes, Plane 'A' and Plane
'B', along the antenna axis. Plane 'A' is at the back
of the antenna and Plane 'B' is in front of the feedhorn.
If AsiaSat 2 is the primary satellite, align the dish
antenna with AsiaSat 2 first. Then find out the position
of the secondary satellite (i.e. AsiaSat 3S) on plane
'A' and the position of the secondary feedhorn on plane
'B'. Align the secondary feedhorn with the secondary axis
by connecting these two points.
Example
To receive both AsiaSat 2 and AsiaSat 3S using a 2.4m
dish antenna in Hong Kong, and assuming AsiaSat 2 is the
primary satellite and AsiaSat 3S the secondary satellite,
the
relative separation angle
will be
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5.24o H
2.43o V |
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| feed offset angle will
be |
-0.102m H
-0.047m V |
where H is horizontal direction and V is vertical direction
In the case of receiving two satellites with a single
dish, the receiving gain for the secondary satellite will
be lower than that of the primary satellite. In order
to compensate this loss, a large antenna or signal booster
may be needed.
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