(3) Mountainous or hilly terrain should be avoided.
(4) The site should be located as far inland from large
bodies of water as possible. Radio signals may bend or reflect
when passing over a shoreline at an angle. Errors are smallest
when signals cross a shoreline at right angles.
(5) The soil around the site should have uniform
conductivity. Non-uniform conductivity will cause HF radio
ground waves to bend and VHF radio space waves to reflect.
(a) Moisture increases conductivity. Pick an
area with uniformly moist soil.
Moist soil gives stronger
reception, but for df accuracy uniformly dry soil is better than
patchy wet soil.
(b) Soil type affects conductivity. Pick an area
with uniform soil type. Rich earth gives a stronger reception than
sandy soil, but for df accuracy uniformly sandy soil is better than
patchy rich earth.
(c) Areas evenly covered with grass or short
vegetation are usually suitable for df operation.
(d) Areas showing scattered bare spaces or
green spaces should be avoided. Such spaces usually indicate
rocks, mineral outcroppings, or underground streams. Such
areas have non-uniform conductivity.