User's Manual

32
Copyright © 2004-2012 by InfiNet Wireless
current goes through the coaxial cable which grounds ODU clamp with the mast
– the mast is grounded via the grounding contour. The direct lightning strike to
the STP service cable (ODU-IDU) is partially terminated on the grounded IDU
case. Partial termination means that the direct lightning strike will probably
destroy an STP cable. The service cable pickups from the electromagnetic
impulses are terminated on the IDU case by the winding shield, and further – on
the IDU grounding.
The end of the STP service cable that is connected to IDU should be
assembled with a Shielded RJ-45 connector. The other end of the STP
service cable (connected to ODU) should be assembled with
unshielded (standard) RJ-45 connector.
IDU is grounded via a three-conductor power cord and a plug containing a
ground. The data & power wires pickups are terminated via IDU protection
scheme (three-conductor power cord and a plug containing a ground).
ODU grounding contour are connected with 100kOhm resistor, and that provides
no static charge accumulation on the ODU case if there are some problems with
its connection to the grounding contour.
Antenna pole, tower, ODU and lightning arrestor should be connected
to the first common grounding contour. Cable thickness should be no
less than 10AWG using corrosion-steady connectors. IDU should be
grounded to the same contour as customer LAN, having the second
common grounding contour.
A special attention should be paid if antenna used is not DC-shorted. In this case
additional lightning arrestor should be used between the antenna and ODU.
Suggested grounding diagram is shown on the picture below.