DIPOLE ANTENNA

TM 11-5820-919-12

4. Connect the black plug of the remaining antenna

1. Attach each dipole antenna wire to the dipole

reel to the GND terminal. Unwind this wire and lay it on

fixture (fig A3-6).

the ground in line with the antenna and in the opposite

2. Determine the length of each leg of the dipole

direction of the antenna support. Unwind the reel until it

from the antenna length chart table A3-1.

is about 1-1/2 times the antenna length and place the

reel on the ground. (When the antenna is completely

3. Connect the coaxial lead-in of the feedline to the

erected, this wire provides a counterpoise.).

BNC connector of the amplifier/coupler. Set ANT SEL

switch to the BNC (middle) position.

5. Throw the lead weighted dacron cord over any

convenient antenna support (such as a tree limb). Then

4. If two antenna supports are available, erect the

fasten the cord reel to the antenna reel. Raise the

antenna as illustrated in figure A3-3. If only one support

antenna and fasten the cord to hold the antenna in place.

is available, use the method shown in figures A3-4 and

A3-5.

A3-5. DIPOLE ANTENNA.. The dipole antenna is the

most effective antenna and, time and tactical

NOTE

circumstances permitting, should be used in preference

In raising a horizontal dipole, considerable pull

to either the whip or slant wire antenna. A dipole

force may be required to raise a long antenna.

antenna is usually erected between two supports as

It is recommended that no more than about

shown in figure A3-3. Antenna supports are not provided

100 pounds pull be applied to the cords used

with this equipment and it is not always possible to find

to raise it, or the wire may break.

two supports that are properly oriented and spaced. If

only one support is available, or if terrain prohibits, a

5. Try to select supports that will enable the height

one-support dipole (figs. A3-4 and A3-5) should be

of the center of the dipole (sloping horizontal, or inverted)

used. Note that for both the dipole and slant wire

to be 1/3 of the leg length given in table A3-1, but never

antennas, the most effective receiving and transmitting

lower than about 10 feet. For example, at 6.0 MHz, the

direction is broadside, or 900 to the line of the wire.

desired height would be 1/3 x 39' = 13' above ground.

Erect a dipole antenna as follows.

This may not be possible at the lower frequencies so

raise the antenna center as high as available supports

will practically allow.

A3-3