Dipole field strength in free space, in telecommunications, is the electric field strength caused by a half wave dipole under ideal conditions. The actual field strength in terrestrial environments is calculated by empirical formulas based on this field strength.
^Reference data for radio Engineers, Howard W.Sams co,Indianapolis, 1956, 27-7
^ K.H.Kaltbeitzer: Site selection, EBU Techhnical Monograph 3104,Bruxelles,1965, p 30
January 31, 2023
dipole, field, strength, free, space, telecommunications, electric, field, strength, caused, half, wave, dipole, under, ideal, conditions, actual, field, strength, terrestrial, environments, calculated, empirical, formulas, based, this, field, strength, conten. Dipole field strength in free space in telecommunications is the electric field strength caused by a half wave dipole under ideal conditions The actual field strength in terrestrial environments is calculated by empirical formulas based on this field strength Contents 1 Power density 2 Numerical values 3 See also 4 ReferencesPower density EditLet N be the effective power radiated from an isotropic antenna and p be the power density at a distance d from this source 1 p N 4 p d 2 displaystyle mbox p frac N 4 cdot pi cdot d 2 Power density is also defined in terms of electrical field strength Let E be the electrical field and Z be the impedance of the free space p E 2 Z displaystyle mbox p frac E 2 Z The following relation is obtained by equating the two N 4 p d 2 E 2 Z displaystyle frac N 4 cdot pi cdot d 2 frac E 2 Z or by rearranging the terms E N Z 2 p d displaystyle mbox E frac sqrt N cdot sqrt Z 2 cdot sqrt pi cdot d Numerical values EditImpedance of free space is roughly 120 p displaystyle 120 cdot pi Since a half wave dipole is used its gain over an isotropic antenna 2 15 dBi 1 64 displaystyle mbox 2 15 dBi 1 64 should also be taken into consideration E 1 64 N 120 p 2 p d 7 N d displaystyle mbox E frac sqrt 1 64 cdot N cdot sqrt 120 cdot pi 2 cdot sqrt pi cdot d approx 7 cdot frac sqrt N d In this equation SI units are used Expressing the same equation in kW instead of W in power km instead of m in distance and mV m instead of V m in electric fieldis equivalent to multiplying the expression on the right by 1000 displaystyle sqrt 1000 2 In this case E 222 N d displaystyle mbox E approx 222 cdot frac sqrt N d See also EditAntennas Effective radiated power Electric field Field strength meter Radio propagation modelReferences Edit Reference data for radio Engineers Howard W Sams co Indianapolis 1956 27 7 K H Kaltbeitzer Site selection EBU Techhnical Monograph 3104 Bruxelles 1965 p 30 Retrieved from https en wikipedia org w index php title Dipole field strength in free space amp oldid 1012243206, wikipedia, wiki, book, books, library,