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Section 3 - Installation (ATSC EC702HP Transmitter)
3.3.4 Equipment Installation Indoors
Small equipments must be placed on a table in a way to provide easy access from all sides and
be at least one meter far from the walls.
Do not place anything on the top of the equipment in order not to compromise its natural ventilation.
The ventilation system equipments must be placed directly on the shelter's floor as long as it is
flat and they must be placed at least one meter far from the walls.
Some of these air outlet must be connected to the outside of the shelter through PVC tubing.
The AC cable has two terminations to be used exclusively in the equipment.
3.3.5 Equipment Grounding
The grounding has to be made separately from the power supply, with a rig and a grounding
terminal that come with the equipment.
Normally, the retransmission sites are located in the highest spot of the chosen location, what
makes them more vulnerable to lightning strikes.
These discharges carry a great amount of electric energy, putting at risk not only the antenna
and its structure but also the equipments in the shelters. In order to minimize this effect and
guarantee their protection and continuous service during thunderstorms with lightning, the use
of a reliable grounding system is paramount.
Lightning is a transient, high-current eletric discharge that happens between the ground and the
clouds therefore the most important part of a lightning protection system are the parts that are
on the ground.In order to maintain the low impedance of the technical grouding system, it must
be carefully executed in a way that the electric field energy is drained away without affecting the
equipment.In order to define a system, the characteristics of the soil resistivity must be taken
into consideration.
To dertermine the behavior of the soil capacity to drain the currents, its resistivity has to be
measured. For an adequate protectionm this value should not exceed 5 , being zero the
ideal value
Generally, the grounding method used for TV retransmitters is a system with a single vertical
electrode made with copper measuring 2.5 meters or more.
In case the conditions and characteristics of the soil are of high resistivity or high incidence of
lightning discharges, the grounding system must be thoroughly analyzed.
It is very important to notice that the grounding systems of the equipments and the lightning rod
are independent and should never be connected to each other. A poorly elaborated grounding
system can cause damages to the equipment that won't be covered by the warranty.
Manual Rev. 0.0 - April 2016
3-4
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