StacksVerified U.S. regulatory reference

16 CFR Part 1512, Table 3

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov
Observation angle (degrees)Entrance angle (degrees)Minimum acceptable value of A
MetersFeet
0.2−42.2 | 7.25
.2201.9 | 6.27
.2401.3 | 4.29
1.5−40.22 | 0.73
1.5200.19 | 0.63
1.5400.13 | 0.43

[43 FR 60034, Dec. 22, 1978, as amended at 45 FR 82631, Dec. 16, 1980; 46 FR 3204, Jan. 14, 1981]