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9 m Monopole Analysis
Reg:
Here is the results of my analysis of a 99 radial monople: Height 9 m, radial length from 0.5 to 10m, all conductors #14 AWG copper, ground Er = 16, resistivity 150 ohm - m. Radials 25 mm below ground. Antenna efficiency includes the surface wave. Radial Radial Radiation Ant Length Z Resistance Efficiency (m) (ohms) (ohms) (%) 0.5 63.0 - j 33.6 13.2 17.6 1.0 47.7 - j 18.2 13.2 21.7 1.5 41.8 - j 13.7 13.2 24.1 2.0 38.3 - j 12.5 13.2 25.7 2.5 35.7 - j 11.2 13.2 27.1 3.0 33.4 - j 10.8 13.2 28.3 3.5 31.6 - j 10.5 13.1 29.4 4.0 29.8 - j 10.1 13.1 30.6 4.5 28.2 - j 9.5 13.1 31.7 5.0 26.8 - j 8.9 13.1 32.8 5.5 25.7 - j 8.2 13.1 33.8 6.0 24.7 - j 8.0 13.2 34.7 6.5 23.9 - j 6.9 13.2 35.6 7.0 23.2 - j 6.2 13.3 36.4 7.5 22.6 - j 5.5 13.4 37.7 8.0 22.1 - j 4.8 13.5 38.0 8.5 21.6 - j 4.2 13.7 38.8 9.0 21.2 - j 3.5 13.8 39.5 9.5 20.9 - j 2.9 14.0 40.2 10.0 20.7 - j 2.2 14.2 40.9 Note that the radiation resistance is computed from the total radiated power (including surface wave) divided by the RMS base current squared. The radial input impedance is derived from the difference between the antenna input impedance and the radiation resistance. A fraction of an ohm can be attributed to the copper losses in the monopole. Also some of the imaginary part of the radial impedance must be due, in part, to the input impedance of the vertical section. With 0.5 m radials the surface wave accounts for 2% of the total radiated power. With 10 m radials the surface wave accounts for 5% of the TRP. Frank CM Reg's 99 radial Vertical CM (WG) CE GW 2 1 0 0 0 0 0.0968 -0.025 0.00082 GW 35 4 0 0.0968 -0.025 0.026 0.5 -0.025 0.00082 GW 70 4 0 0.0968 -0.025 0 0.5 -0.025 0.00082 GW 105 4 0 0.0968 -0.025 -0.026 0.5 -0.025 0.00082 GR 1 33 GE -1 2 GN 2 0 0 0 16 0.0067 FR 0 1 0 0 8.07 0.01 LD 5 0 0 0 5.8001E7 WG EN CM Reg's 99 radial CM (GF) CE GF GW 1 90 0 0 9 0 0 0 0.00082 GE -1 EX 0 1 90 00 83.83328192 0 LD 5 0 0 0 5.8001E7 RP 1 101 1 0000 200 0 -2 1 200 RP 0 91 1 1000 0 0 1 1 RP 0 19 73 1002 -90 0 5.00000 5.00000 NE 1 1 46 1 200 45 90 1.0 1.0 1 NH 1 1 1 1 200 89 90 1.0 1.0 1 EN |
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