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Chapter 4. LOW NOISE BLOCK
This chapter provides the description and operation for a LNB.
4.1
Description
The LNB amplifies the input Ku-Band signal and down converts it to L-Band in the
range of 950 to 1750 MHz (there may be instances that the L-Band range = 950 to 1450
MHz ). The choice of which downlink frequency band is determined by the selection of
a frequency range, usually from one of LNBs in the following bands:
LNBs are available that are either externally referenced (EXT REF) or internally
referenced (INT REF).
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The standard LNB noise temperature is: For C-Band < 35°K.
Optional: A TX Reject Filter (TRF) may be obtained with the system or supplied by
the customer.
DOWN CONVERTER
For C-Band
3.625 to 4.2 GHz
4.50 to 4.80 GHz
The EXT REF LNB accepts an external 10 MHz reference from the IDU. These
units have the best phase noise performance and the lowest frequency drift.
The INT REF LNB includes its own internal oscillator. DC power is supplied to
the LNB through the IFL cable from the IDU.
For Ku-Band
10.95 to 11.70 GHz
11.70 to 12.20 GHz
12.25 to 12.75 GHz
For Ku- Band < 65°K.
4–1
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