Справочник Пользователя для Infinet Malta Limited LM-5X18
InfiNet Wireless R5000
Technical User Manual
Copyright © 2004-2010 by InfiNet Wireless
25
Grounding when using IDU-LA
Antenna must be placed on the mast on the level that is at least 1 meter lower
than a mast‘s top. In this case it is of big probability that the lightning strikes the
mast and not the antenna. The mast is to be grounded on the grounding contour
mast and not the antenna. The mast is to be grounded on the grounding contour
according to your local standards. When the lightning strikes the antenna, the
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
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
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 grounding contour.
impulses are terminated on the IDU case by the winding shield, and further – on
the grounding contour.
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.
unshielded (standard) RJ-45 connector.
The data & power wires pickups are terminated via IDU protection scheme
(discharger and additional air gap). ODU and IDU grounding contours 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
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 must be connected
to the first common grounding contour. Cable thickness must be not
to the first common grounding contour. Cable thickness must be not
less than 10AWG using corrosion-steady connectors. Grounding
contour development must be done by the skilled personnel.
contour development must be done by the skilled personnel.
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.