Fastening Of Cables, Antennas And Connectors - Hitachi EC702MP-BB3 Operation Manual

The following information about the tower must be obtained:
a) It features a special insulator support for descent of cordage of the lightning rod with a maximum
space of 1.5m between them.
b) There must be lightning signaling system every 20m along the tower.
c) It must be painted with orange and white stripes every 2m with special paint that complies with
local regulations.
d) It must endure winds of up to 150 Km/h.
In a retransmission station the tower is the highest and therefore the most vulnerable device to be hit by
lightning. Because of this the tower is used as a part of the protection system. The lightning protection
device used in these cases is called a lightning rod and has the function of guiding the electrical discharge
safely, avoiding other parts of the system that could be hit and damaged by it.
The use of a lightning rod is MANDATORY. The project and installation of grounding and lightning
protection systems must be performed by specialized companies. Eventual damage to the equipment
caused by missing or malfunctioning arresters are not covered by warranty.

3.3. Fastening of cables, antennas and connectors

Please observe the following items when installing antennas:
Direction of Antennas and Aperture Angles
Use a pocket compass when directing the antenna and a field strength meter for the fine adjustment of
the reception antenna.
Height
It mainly depends on the receiving signal and the transmission conditions (obstructions, attended area,
etc). It's very important to verify how far the antenna is from the lightning protection device, since the
antenna must stay inside its cone protection.
Distance between the Rx and Tx Antennas
They should be placed as far as possible from each other in order to isolate the transmitted signal from
the received signal.
Polarization
It is very important to verify the polarization of the received signal, which can be vertical, horizontal or
circular.
Phasing
When receiving a signal with vertical polarization, the system must be mounted vertically, otherwise the
gain of the antenna will be drastically reduced, likewise in case of a signal with horizontal polarization.
To receive a signal with circular polarization with a non-circular antenna, the system can be mounted either
vertically or horizontally.
E-Compact MP-BB3 Series
88 | 108