Alcad 912-TP, Руководство пользователя

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3. INSTALLATION
The drawings in the ANNEX show how to perform the assembly and the
standard connections.
3.1 Placing of 75
Ω Ω
load
Except the TEST output of the PA amplifier, verify that the remaining unused
inputs and outputs are loaded with an RS-275 (cod. 9120011) load of 75
Ω .
3.2 Installation of external LNB units
It is very important to make a note of the dish, the quality of the digital
signals, which fade out very much when it is not properly recorded down (in
spite of being good for analogic signals).
Correctly adjust the skew of the external LNB unit to get the best possible
cross polarisation. This adjustment is fundamental for high quality reception
of the digital signal. The cross polarisation must be 20 dB lower than the
level of the digital signals.
Fig. 6 - Adjusting the LNB
Verify that the external LNB units are supplied. To do so, turn the +V LNB
(21) switch on in one of the TP modules that are directly connected to each
LNB unit.
28 - ENG Installation and programming manual
LNB
≥
20dB