TM 9-2350-275-BD
11-21. GROUND PLANE FIELD EXPEDIENT ONE-QUARTER WAVE ANTENNA
General Information
This procedure gives instructions for construction of a one-quarter wave ground plane
antenna which can be used for transmission and reception. This antenna has the
capability of increasing the range of FM radios.
Limitation
q Can only be used on a stationary vehicle and when a tree is available for suspension
of the antenna
Personnel/Time Required:
q 1 soldier
q 30 minutes
Materials/Tools:
q Cable, l-roll, telephone, WD-1/TT
q Insulators (e.g., glass, plastic, leather, nylon, etc.)
(Five required)
q Rope
q Sticks or branches, 3-foot length, (three required)
Other Option:
q For reception only, field expedient auxiliary antenna. (Refer to para. 11-19.)
Procedural Steps:
1.
Determine the length of wire needed for the radiating element of a one-quarter
wave antenna using the following formula:
. 234 divided by frequency (MEGAHERTz)
Length (feet)
or
Length (meters)
Example- A radiating element for a frequency of 50 MHz
L (feet)
= 234 divided by 50 MHZ = 4.68 feet
or
L (meters)
= 71.37 divided by 50 MHZ = 1.43 meters
11-22