Comtech EF Data LCS-4 - Manual (Page 29)

Chapter 4. LOW NOISE BLOCK
ASSEMBLY
4.1 G
ENERAL
The Low Noise Block (LNB) amplifies the input RF 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:
For C-Band, GHz For Ku-Band, GHz
3.625 to 4.2
4.50 to 4.80 10.95 to 11.70
11.70 to 12.20
12.25 to 12.75
LNBs are available that are either externally reference (EXT REF) or internally referenced
(INT REF).
• 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.
The standard LNB noise temperature is: For C-Band < 35 °K
For Ku-Band < 65 °K
Optional: A TX Reject Filter (TRF) may be obtained with the system or supplied by the
customer.
4–1