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3.2.3.2 Connector Details - L-Band Input

Cautions!

The Receiver provides DC power via the active L-band input connector to drive an

LNB (Low Noise Block Down-Converter). Do not connect equipment other than an

LNB to this connector. Failure to do this may result in damage to the external

equipment

The F-type connector is not suitable for repeated connection and disconnection.

When intended for use in this way, fit a sacrificial connector and connect to it.

Connect the L-band output of a suitable LNB to the F-type connector either directly

or via a suitable attenuator giving adequate consideration to lightning and surge

protection (see page 3-5).

The specification for this connector is given in Annex B, Technical Specification.

Table 3.4: QPSK Satellite Receiver (L-band) Connector

Input Specification

Connector Type F-type, Female

Connector designation QPSK IN

Pin: Centre

Shield

RF Input

Ground/Chassis

LNB Supply Refer to the previous caution box

Impedance

75 Ω

3.2.4 Use of an Attenuator

The L-band input can be connected via a suitable attenuator to give adequate

consideration to lightning and surge protection.

In most cases an attenuator will not be required. The following list summarises the

circumstances in which one should be used.

1. If the wanted input level is greater than the specified maximum permissible

(-25 dBm)

2. If the downlead is a short length of low-loss cable and the LNB in use has a poor

return loss (7 dB min)

3. If the receiver is receiving one of many carriers in a multi-carrier FDM system

and the level of the wanted signal is close to the specified maximum permissible

EN/LZT 790 0002/2 R1A

3-5

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Ericsson TT1222 Guia do Utilizador Página 43