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GENERAL INFORMATION
The DB404 series is a heavy duty, light weight antenna for
use where an omni-directional or an elliptical radiation pat-
tern is desired.
OPTIONAL RADIATION PATTERN
One important feature of the DB404 series antenna is that it
permits the user to adapt the antenna to changing coverage
requirements. When the dipole element pairs are spaced at
90° to each other, an omni-directional or circular pattern re-
sults. When both sets of dipoles are in line (collinear - see
the DB404L illustration in Figure 1), the antenna has a di-
rectional characteristic, giving an elliptical pattern as shown
in Figure 2. Also, see Figure 3 for gain variation with fre-
quency for DB404 and DB404L antennas. The change from
one radiation pattern to the other is easily accomplished.
The banding clamps that hold the dipole elements against
the mast and the tape securing the antenna harness to the
mast are loosened. The top elements are rotated around
the mast as indicated in Figure 1, then the clamps again
securely tightened. Retape the antenna harness to the mast
- covering the tape that secures the cabling harness to the
mast with an aluminum backed tape such as Scotch #425.
(Part # DB11901)
GENERAL MOUNTING INFORMATION
The DB404 series antenna is designed for mounting on the
top of a tower or wooden pole. For best operation, it is rec-
ommended that the bottom dipole be above the tower. Side
mounting of the antenna requires the use of a DB5007 side
mount kit. Radiation patterns obtained with the antennas
side mounted on a 18" tower are shown in Figure 4.
Figure 1. Dipole Arrangement For Pattern Performance
Installation Instructions
Bulletin 095022-000
Revision K • September 2003 • Page 1 of 2
Broad Band Antennas – Omni/Elliptical
DB404
NOTICE
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.
DB404
(Omni pattern)
DB404L
(Elliptical pattern)
Figure 2. Azimuth Pattern with Respect to Half Wave Dipole
DB404 DB404L
Do not install near power lines. Power lines,
telephone lines, and guy wires look the same.
Assume any wire or line can electrocute you.
Do not install on a wet or windy day or when
lightning or thunder is in the area. Do not use
metal ladder.
Wear shoes with rubber soles and heels.
Wear protective clothing including a long-
sleeved shirt and rubber gloves.
(continued on page 2)