MFJ All Band Doublet Instruction Manual
2
INSTALLING THE ANTENNA
The best location for this antenna is as high and far away as possible from utility
wires, other antennas, and other structures. It is difficult to find a perfect
location, so the best compromise usually must be accepted. The antenna can be
installed in three basic ways:
Horizontal Antenna:
Requires two tall supports separated by more than 102
feet. Suspend the antenna with at least a 50 pound working load nylon rope or
another equivalent strength weather resistant non-metallic rope. Never use wire
or wire core rope to support the ends of the antenna. Attach the rope to the end
insulators through the empty holes.
Try to keep the antenna as horizontal as possible. The antenna must be more
than 35' above ground level to give acceptable performance, and as high as
possible for the best overall performance. The ladder line should drop vertically
from the horizontal section for
at least
20 feet and should be kept several inches
from conductive objects. If the antenna's ladder line has to be installed near
conductive objects, space the line at least 6" from the object with non-
conductive supports (for example: PVC pipe standoff supports 6" long). Use
nylon cable ties to secure the feedline to the supports.
Be sure to allow enough slack or use some type of pulley and counterweight
system to prevent the antenna or rope from breaking if the trees move in the
wind. It is also possible to use masts, towers, or other tall structures for
supports. Try to keep the ends of the antenna at least
five feet from metallic
supports.
Inverted "V" Antenna:
This method requires only one tall support and also
places the least strain on the antenna. Hang the center insulator of the antenna
from the support using a nylon rope or other non-conductive rope tied to the
center hole of the center insulator. The center insulator should be the highest
point of the antenna. The antenna ends should be less than 25.5 feet below the
center insulator. This avoids an inside angle of less than 120 degrees between
the antenna's legs. The antenna ends should be secured with nylon or weather
resistant non-metallic rope to suitable supports.
Sloper Antenna:
This antenna can also be suspended as a sloping dipole. This
requires one tall support and one short support. The center of the antenna must
IMPORTANT: Use weather resistant rope rated at
at least 50 pounds working load to support this antenna.
