ISSN:
0197-8462
Schlagwort(e):
microwave
;
cellular-radio
;
potential exposure
;
electromagnetic environment
;
Life and Medical Sciences
;
Occupational Health and Environmental Toxicology
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Biologie
,
Physik
Notizen:
Because of a heightened public awareness of issues pertaining to the use of electromagnetic energy, concurrent with a rapid growth of the cellular telephone industry, a study was initiated to characterize the electromagnetic environment associated with typical cellsite antennas. In particular, the radio-frequency electromagnetic (RF) fields in the vicinity of several antenna towers, ranging in height from 46-82 m, were characterized by measurement. In all cases, the antennas were omnidirectional co-linear arrays. The maximal power densities considered representative of public exposure were found to be less than 100 μW/m2 (10 nW/cm2) per radio channel. Comparison of measured values with the corresponding values that were calculated from the free-space transmission formula indicated that the analytical technique is conservative (i.e., overestimates field levels). The measured and corresponding analytical values were found to be well below accepted exposure limits even when extrapolated to simultaneous and continuous operation of the maximal number of transmitters that would be expected to be installed at a cell-site. Additional measurements were made in the near field of the same antenna type in a roofmounted configuration. At a distance of 0.7 m from the antenna, the maximal power density in the main beam was found to be less than 30 W/m2 (3 mW/cm2) when normalized to sixteen radio channels (the maximal number used on a single antenna) and less than 30 mW/m2 (3μW/m2) at 70 m. In all cases, the effective radiated power (ERP) by each radio channel was 100 W referenced to a half-wave dipole. This paper describes the instrumentation and measurement techniques used for this study and provides a summary of the results. 1992 Wiley-Liss, Inc.
Zusätzliches Material:
10 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/bem.2250130608
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