Andrew DB222 Series Einbauanleitung
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Installation Instructions
Broadband Antennas
DB222 Series
GENERAL INFORMATION
DB222 broadband antennas are lightweight and equipped
with two dipoles for transmit and receive applications.
ELECTRICAL DESIGN
Either an offset or circular (omni) pattern can be achieved,
depending on the direction in which the two dipoles are ar-
ranged. For a circular (omni) pattern, the two dipoles are
staggered on opposite sides of the mast to provide a gain
of 3 dB over a vertical half-wave dipole. For a collinear pat-
tern (offset), the two dipoles are positioned in line to provide
a forward gain of 6 dB, with 3 dB on the sides and -1.5 dB
on the back. The dipoles can be easily changed in the field.
See Figure 1.
LIGHTNING PROTECTION
The radiators operate at dc ground, and the aluminum mast,
with its pointed cap, provides a low resistance discharge path
to the tower or ground system.
BANDWIDTH
The bandwidth permits the antenna to perform efficiently on
both transmit and receive frequencies. Through the use of
a suitable duplexer, a single DB222 and transmission line
can be used for simultaneous transmission and reception
when used in DUPLEX or MOBILE REPEATER operations.
This arrangement avoids the differing coverage patterns that
occur when one antenna is mounted on top of another on
the side of a tower, and it gives maximum gain for transmit
and receive.
MOUNTING
The DB222 is mounted using DB365-OS mounting clamps,
which are included. The DB365-OS mounting clamps are
designed for top mounting to the tower. For side mounting, the
DB5001 mounting hardware must be ordered separately.
The installation, maintenance, or removal of an antenna
requires qualified, experienced personnel. Andrew
installation instructions are written for such installation
personnel. Antenna systems should be inspected once
a year by qualified personnel to verify proper installation,
maintenance, and condition of equipment.
Andrew disclaims any liability or responsibility for the results
of improper or unsafe installation practices.
NOTICE
DB222
3 dB Gain
Omni Pattern
Figure 1. Dipole Arrangement for Achieving Pattern Shaping.
Do not install near power lines.
Do not install on a wet or
Power lines, telephone lines,
windy day or when
and guy wires look the same.
lightning or thunder is
Assume any wire or line can
in the area. Do not use
electrocute you.
metal ladder.
Installation Training Available at Andrew Institute
Bulletin 095007-000
Revision F • July 2006 • Page of 2
DB222E
6 dB Gain
Offset Pattern
(continued on page 2)
Wear shoes with rubber soles
and heels. Wear protective
clothing including a
long-sleeved shirt and rubber
gloves.