relatively high on the slopes should be selected. Locations at the base of a
cliff or in a deep ravine or valley should be avoided.
For operation at
frequencies above 30 MC, a location that will give line-of-sight communications
should be selected whenever possible.
(2)
Dry ground has high resistance and limits the range of the
radio set. If possible, the station should be located near moist ground, which
has much less resistance.
Water, and in particular salt water, will greatly
increase the distances that can be covered.
(3)
Trees with heavy foliage absorb radio waves, and leafy trees
have more of an adverse effect than evergreens.
The antenna should be kept
clear of all foliage and dense brush.
b.
Man-made obstructions.
(1)
A position in a tunnel or beneath an underpass or steel bridge
should not be selected. Transmission and reception under these conditions are
almost impossible because of high absorption of RF waves.
(2)
Buildings located between radio stations, particularly steel
and reinforced concrete structures, hinder transmission and reception.
(3)
All types of pole wire lines, such as telephone, telegraph,
and high-tension power lines, should be avoided when selecting a site for a
radio station. Such wire lines absorb power from radiating antennas located in
their vicinity.
They also introduce hum and noise interference in receiving
(4)
Positions adjacent to heavily traveled roads and highways
should be avoided. In addition to the noise and confusion caused by tanks and
trucks, ignition systems in these vehicles may cause electrical interference.
(5)
Battery-charging units and generators should not be located
close to the radio station.
(6)
Radio stations should be located close to each other.
(7)
Radio stations should be located in relatively quiet areas.
The copying of weak signals requires great concentration by the operator, and
his attention should not be diverted by extraneous noises.
76.
Tactical Requirements.
a.
Local command requirements. Radio stations should be located some
distance from the unit headquarters or command post
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