© Proeye Communications & Security Systems 2011
Q) I am receiving signals in the C-Band range which is 3.7-4.2GHz in Australia and at times the picture pixelates.
A). There can be a number of reasons what causes the received broadcasts to pixelate and can be related to;
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Alignment of the dish, as it may have moved slightly out of position causing the signal level to drop out from time to time, or
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Faulty LNB, I have had to replace faulty LNB's which were not operating correctly any more, or
•
Wireless telecommunications services causing interference to typical wideband or poorly designed LNB’s. Wideband LNB’s which
have an input range of 3.4-4.2GHz. are more susceptible to interference caused by the increasing number of telecommunications
services using the 3GHz spectrum. Suitable 3.7-4.2GHz LNB’s with high rejection is usually required resolve most interference
issues affecting the LNBF.
•
Some types of interference signals may be within the 3.7-4.2 GHz range and can be more costly to resolve.
From experience we have found in some instances moving the satellite dish to another location on the property
resolves the problem, reducing the need to purchase expensive filters.
Q) Why are other transmitters allowed to cause interference to my satellite reception?
Local telecommunications services can be licensed to operate adjacent or within the satellite C-Band spectrum which ranges from 3.7 to 4.2 GHz in Australia.
Services include WiMax and point to point radio links. These local services can cause harmful interference to C-Band satellite receiving systems which in most
situations can be resolved. If the interference is in the adjacent spectrum, for example 3.5GHz, then changing the LNBF can solve the problem. Most off the
shelf domestic LNBF’s use an input range of 3.4 to 4.2 GHz and amplify the signal from 60 to 63 dB or approximately by a factor of 1 to 2 million. Therefore
the signal from a local transmitter service operating at 3.5 GHz will cause severe interference to the LNBF. To resolve the problem the LNBF should be replaced
with a suitable LNB or LNBF that uses the correct input range of 3.7 to 4.2 GHz. In some cases where the signal from the local telecommunications service
is at extremely high levels, the satellite TV receiving system requires a commercial LNB engineered to withstand the adjacent signals, which we have available.
The photo below illustrates a real example of a commercial LNB we applied to resolve extremely high levels of interfering signals caused by a local
WiMax service at 3.5GHz at Werribee Victoria.
Satellite interference tip!
Diagnostic Service
We provide diagnostic service to identify and resolve satellite reception interference issues.
If your satellite or TV picture often pixelates and you cannot resolve it,
contact us and we may be able to resolve it for you!
Satellite Interference
information
Intelsat Interference
to C-Band Presentation
European Satellite
Operators Association
Satnews Daily - C-Band
FrequencySpectrum
Safeguard (But not
Australia as it is in Region 3)
SUIRG, Inc, When
Broaddband Wireless
and Satellite Services Collide
SUIRG
Communications Day,
issue 3035, Satcom,
broadcast & 3G lobbies
slam ACMA wireless
broadband proposals
SatMagazine, Satellite and
WiMax
Asia-Pacific Telecommunity
Fixed Satellite service and
WiMax coexistance
ITU Speech Houlin Zhao
ITU Dep Secretary-General
CASBAA Satellite Industry
Forum 2009