Chapter 12 EMF (EMI) Operation
Measurement antennas
188 9102 Handheld Spectrum Analyzer Software version 5.31
Measurement antennas
The antenna is one of the most important factors in EMF measure-
ments. There are different types of antennas which can be used for
measuring field strength depending on your measurement require-
ments. Aeroflex offers a range of antennas for different measurement
requirements:
– The 9170 Biconical Antenna with a frequency range from 60 to
2500 MHz for immission measurements
– The 9171 Isotropic Antenna with a frequency range from 50 to
3000 MHz for immission measurements
– The 9172 and 9173 Directional Antennas, two antennas with a
frequency range of 80 to 1000 MHz and 300 to 3000 MHz
respectively for emission measurements
For ordering details for Aeroflex antennas and antenna accessories
refer to “Options and accessories” on page 5.
During measurements the antenna converts the free progressive wave
into a line wave. For antenna calibration a correction table containing
k factors is required. These factors are proportionality factors which
correct the antenna’s frequency response and help to convert the
measured power or voltage to field strength or power density. Using
the k factor table the measured level is converted into the relevant
quantities, the field strength measured in V/m and the power density
measured in W/m
2
.
Aeroflex delivers its measurement antennas in conjunction with the
appropriate correction factor tables. Using the 9100 Data Exchange
Software you can transfer the k factor tables delivered to your instru-
ment. With the 9171 Isotropic antenna this step is not neccessary as
the factors are stored in a memory inside the antenna interface. You
can also use the 9100 Data Exchange Software to collect the correc-
tion data for antennas from other vendors and transfer them to your
9102. For further details on using the 9100 Data Exchange Software
refer to Chapter 15 “9100 Data Exchange Software”. After transferring
the correction tables to the instrument they will be available for selec-
tion for EMF measurements.
Aeroflex also offers antenna accessories like a tripod as well as cali-
brated cables. Thus you will be able to master any situation in the field
using the 9102 and its accessories. If you use a tripod and cable setup
for your measurements, cable attenuation is taken into account by acti-
vating the appropriate cable factor on the instrument.
Following is a general technical description of the different measure-
ment antenna types providing information on the relevant measure-
ment purpose as well as technical details. For a detailed description of
all individual steps to be taken during EMF measurements using the
different measurement antenna types refer to “Performing automatic
measurements” on page 203 and “Performing manual measurements”
on page 207.
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