Chapter 12 EMF (EMI) Operation
Measurement methods
9102 Handheld Spectrum Analyzer Software version 5.31
185
– Measurements for determining radiation exposure of
representative and especially sensitive facilities, e.g. schools,
nursery schools and hospitals situated in proximity of transmitter
sites
– Long-term measurements for determining immission fluctuations
Measurement setup for
immission measurements
As for emission measurements you just need two pieces of equipment
for performing immission measurements with the 9102:
– 9102 Handheld Spectrum Analyzer equipped with the
9131 EMF Measurement Option and the 9132 RMS Detector
Option
– 9170 Biconical Antenna (for a detailed description refer to “9170
Biconical Antenna” on page 189)
or
– 9171 Isotropic Antenna (for a detailed description refer to “9171
Isotropic Antenna” on page 191)
The type of antenna you use depends on your measurement require-
ments. The detailed descriptions of the two different antenna types in
“Measurement antennas” on page 188 provide you with useful infor-
mation for selecting the appropriate measurement antenna for your
EMF measurement.
In this measurement setup the 9102 captures the electromagnetic
waves from all directions and displays the overall field strength in the
desired frequency range.
Measurement methods
The location for performing EMF measurements is usually predefined.
A main goal of performing EMF measurements is determining the radi-
ation people are exposed to in their everyday life, so the measure-
ments are usually done at locations where people stay for a while, e.g.
their work place, home, but also restaurants or sidewalks etc. At the
measurement locations a search for the maximum field strength has to
be performed in order to determine the radiation exposure caused for
example by mobile network base stations. For longterm EMF measure-
ments first the maximum field strength is determined and then the
antenna is placed on the location of maximum exposure. Basically
there are two methods for determining the maximum field strength
within a designated measurement area:
– The stirring method or
– the multipoint method
Using each of the two methods the user will move with the antenna
within the area to be measured as shown in the following graphic
depicting a user determining the maximum field strength using a
measurement setup involving an isotropic antenna.
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