Chapter 5 Main Antenna Feeder System
The principle of the electrical tilt is as follows:
The adjustment of the phase of the antenna array vibrator changes
the maximum vertical and horizontal components and alters syn-
thesized field strength, thus making the vertical pattern of the
antenna declining. Because the antenna field strength increases
or decreases simultaneously in all directions, which ensures that
the antenna pattern hardly varies with the tilt. This diminishes the
coverage of the main lobe and ensures that no interference occurs
when the coverage of the whole pattern decreases in its service
area.
Feeder Structure
The feeder is used to receive and transmit radio RF signals between
the antenna and the ZXSDR BS8800 C100. There are many types
of feeder cables such as 1/2 inch and 7/8 inch feeder cable.
When the distance between the ZXSDR BS8800 C100 cabinet and
antenna is less, then 1/2 inch feeder cable is used. In this case,
ZXSDR BS8800 C100cabinet is directly connected to the 1/2 inch
feeder and 1/2 inch feeder cable is connected to antenna.
When the distance between theZXSDR BS8800 C100 cabinet and
antenna is more, then 7/8 inch feeder cable is used. In this case,
ZXSDR BS8800 C100cabinet is first connected to the jumper, then
jumper is connected to 7/8 inch feeder cable, and 7/8 inch feeder
cable is again connected to jumper and lastly jumper is connected
to antenna.
The antenna may have N type or DIN type interface. The feeder
is adapted to female and male N connectors. Usually both ends
of the delivered feeder are male N connector to facilitate on-site
installation.
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