For many years the ARRL Antenna Book has provided a table like this. Antenna analysis programs have adopted the values and they are widely used. However, the table is for the AM broadcast band. Since ground constants are anything but constant, the ARRL values are not suitable for HF where they are commonly employed.
The ARRL data originally appeared in the FCC publication Standards of Good Engineering Practice Concerning Standard Broadcast Stations in 1939. Inductivity is an obsolete term for dielectric constant. Conductivity is in EMU (10−14 = 1 mS/m).
1.8 3.7 5.3 7.1 10.1 14.2 18.1 21.2 24.9 28.5
■ 86 119 64 128 55 133 49 137 42 142 36 148 33 152 31 154 29 157 27 159
■ 60 40 43 47 36 51 32 54 27 58 23 63 21 66 19 68 18 71 17 73
■ 20 3.6 17 5.0 16 5.9 15 6.8 14 8.0 13 9.3 13 10 12 11 12 12 12 13
■ 13 .83 12 1.2 12 1.5 11 1.8 11 2.2 10 2.6 10 3.0 9.8 3.3 9.6 3.6 9.4 3.9
■ 11 .44 9.5 .61 8.9 .72 8.4 .82 7.8 .96 7.3 1.1 6.9 1.2 6.7 1.3 6.5 1.4 6.3 1.5
■ 4.7 .071 4.1 .10 3.8 .12 3.6 .14 3.3 .17 3.1 .20 3.0 .22 2.9 .24 2.8 .26 2.7 .28
George Hagn of SRI International developed these curves in the 1980s. The table lists permittivity followed by conductivity in mS/m for the ham bands. Use this interpolator to better represent your terrain. For best antenna model accuracy, use a ground probe or low antenna to measure your soil. Otherwise use the Hagn values.
Seawater permittivity and conductivity are constant over HF but vary with salinity and temperature. In nonpolar, open ocean, permittivity ranges from 70 to 80 and conductivity from 3000 to 6000 mS/m. This map shows ocean conductivity but does not resolve coastal values, which vary with local freshwater discharge. Use Deep Dive in this map to find seawater conductivity along the U.S. coast (divide µS/cm by 10 for mS/m). Calculate permittivity with this program after finding local salinity and temperature with this map. 75 and 4500 mS/m are reasonable generic values for open ocean.
Freshwater permittivity is constant over HF but varies with temperature:
°C °F Permittivity 0 32 88 5 41 86 10 50 84 15 59 82 20 68 80 25 77 78 30 86 77
Freshwater conductivity is constant over HF but varies with temperature and widely with location, e.g., 4 to 29 mS/m for individual Great Lakes and 20 to 100 mS/m for major rivers. Use Deep Dive in this map to find local U.S. values (divide µS/cm by 10 for mS/m). Absent local data, 15 mS/m is a reasonable generic value for a lake.
0.137 0.475 ■ 307 113 166 115 ■ 205 37 112 38 ■ 60 2.6 34 3.0 ■ 29 .41 19 .55 ■ 20 .19 14 .27 ■ 6.3 .024 5.2 .039
I extrapolated the Hagn generic values at 2 MHz to the lowest ham bands with the Messier soil model.
50 98 146 ■ 22 171 16 191 14 206 ■ 13 80 10 92 9.1 101 ■ 10 16 9.1 20 8.6 24 ■ 8.9 5.0 8.4 6.8 8.2 8.2 ■ 6.1 2.0 5.9 2.7 5.8 3.3 ■ 2.7 .37 2.6 .51 2.6 .62
I extrapolated the Hagn generic values at 30 MHz to VHF.
G. H. Hagn, "Ground Constants at High Frequencies (HF)" mistitled "HF Ground and Vegetation Constants" in Proceedings of Third Annual Review of Progress in Applied Computational Electromagnetics, Monterey, CA, 24–26 March 1987.
H. W. Parker and Withan Makarabhiromya, "Electric Constants Measured in Vegetation and in Earth at Five Sites in Thailand," Special Technical Report 43, SRI Project 4240, Stanford Research Institute, Menlo Park, CA, December 1967. Primary data source for the Hagn generic curves.
88–108 MHz