User Manual

SRU Installation
17286-1000 Rev. B 03/14/01
SRU Inst alla tion Manual
2-3
• TNC Male to TNC Female right angle adaptor
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Lightning arrestors (not part of Netro equipment or installation)
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Ground wire (not part of Netro equipment or installation)
2.2 .1.2
2.2 .1.22.2 .1.2
2.2 .1.2 Coax ial Cable
Coax ial CableCoax ial Cable
Coax ial Cable
A coaxial cable is used for the connection between the Subscriber Access System (SAS) and
the Subscriber Radio Unit (SRU). Use only coaxial cable meeting the specification. An
undamaged, unconnected coaxial cable should have a very high resistance between center
and ground. Cables reading less than 10 MOhms should be carefully inspected for water
ingress or connector corrosion. This must be verified on site prior to installation. The cable
generally must pass from an indoor location of the SAS to an outdoor location of the SRU.
When installing the cable, consult local regulatory authorities and follow all local building
codes. When laying out the coaxial cable, include enough cable for a service loop of at
least 18 inches (0.5 m) at the SRU. When the main cable is LMR400, remember to use a
12-inch (0.30m) length of LMR240 for the final connection to the SRU, to avoid overloading
the connector due to the weight of the LMR400 cable.
The SAS and the SRU have female TNC 50 Ohm connectors. The LMR400 cable, if used,
should not be connected directly to the TNC connector because of its weight. The LMR400
would be terminated with “N” connectors rather than TNC. A one-meter length of
LMR240 with N on one end and TNC on the other, is recommended to connect the main
LMR400 cable to the SAS or SRU, and for this reason it is included in the Installation Kit.
Ensure that the connector is dry and free of corrosion prior to connection. E ven a small
amount of dampness could cause corrosion, and signal problems in the cable.
2.2 .2
2.2 .22.2 .2
2.2 .2 Grounding Re com me ndat ions
Grounding Re com me ndat ionsGrounding Re com me ndat ions
Grounding Re com me ndat ions
Prior to installation, determine that the proper source voltage (AC or DC) is available,
properly fused, along with appropriate grounding facilities. The positive terminal of the
source -48 Volts must be connected to the ground. A negative ground supply can cause
power shorts.
ATTENTION
A ll grounding and lightning protection must meet local building codes and ordinances.
N etro is not responsible for damage to equipment or collateral damage or problems
resulting from improperly grounded or protected equipment.
Grounding and lightning protection must meet local building codes. The following
information provides a guide to the connections available for the AirStar system and some
suggestions that may be appropriate, depending on local codes.