standards and guidelines for communication sites - Radio And ...

STANDARDS AND GUIDELINES FOR COMMUNICATION SITES SITE PREPARATION CONSIDERATIONS
Combined Resistance (% of Single Rod Resistance)
100
50
40
30
20
10
Line drawn from intersection
solves system Ω to be 18% of
single-rod Ω
5
4
3
2
1
S =
1 2 3 4 5 10 20 30 40 50 100
Number of Rods
Because eight rods are used, “8” line on
Number of Rods in graph is selected
Because rod spacing is 4.9 m
(16 ft.), or “2L” of rod length,
“s=2L” line on graph is selected
FIGURE B-10 EXAMPLE CALCULATION OF GROUND RODS ARRANGED IN STRAIGHT LINE
68P81089E50-B 9/1/05 B-23
S = L
S = 2L
S = 3L
S = 4L
8