ETS-Lindgren HI-3604 ELF Survey Meter - Manual (Page 32)

Page -- 24 HI-3604 Manual
Figure 5-1
Figure 4-1 shows how the electric field can be perturbed by the
body; localized enhancement of the electric field will lead to a
decreased field strength in other nearby areas. This inherent
shielding effect of the body, unless the body is sufficiently
distant from the instrumentation, can lead to inaccurate
measures of the electric field strength. Depending on the
proximity of the body and its orientation, the perturbation effect
of the body can lead to either enhanced electric field strength
readings or reduced readings when compared to the true
unperturbed field strength. While in some cases it may be
desirable to determine the enhanced fields near objects, in
general, most field measurements should be directed toward
assessing the unperturbed values. Unperturbed field strengths,
for example, or so called free space values, are more easily
related to internal induced currents in the body. Induced
currents represent one potential dosimetric measure of electric
field exposure.
Measurement of the electric field strength beneath power lines
may also be accomplished by laying the HI-3604 on its back