text: Communications
  SITE
  6-105. Another consideration is the site itself. The tactical situation usually determines the antenna
  positions. The ideal area is clear and flat with no trees, buildings, fences, power lines, or mountains.
  Unfortunately, the tactical communicator seldom finds such a perfect site, so he just tries to find one as flat
  and clear as possible. He will often have to settle for less ideal sites, and these sites usually interfere with
  the patterns and functioning of the antennas.
  COMMON TYPES OF ANTENNAS
  6-106. Common antenna types include the half-wave dipole, inverted "V," long wire, and the
  sloping "V."
  HALF-WAVE DIPOLE
  6-107. The half-wave dipole antenna is a balanced resonant antenna (Figure 6-13). It produces its
  maximum gain in a narrow range between 2 percent above and 2 percent below the design frequency.
  Since frequency assignments are normally several megahertz apart, the operator must build a separate
  dipole for each assigned frequency.
  Figure 6-13. Half-wave dipole antenna.
  Length of Dipole
  6-108. The operator calculates the length of a half-wave dipole using the formula
  length = 468/frequency, as shown in Figure 6-14.
  Height of Dipole
  6-109. The operator normally keeps the height of a dipole between one-fourth and one-half wavelength
  above ground level for long-range sky wave. For NVIS of 0 to 300 miles, and for inverted and sloping "V"
  antennas, the operator raises the antenna between one-eighth and one-fourth wavelengths above
  ground level.