ETS-Lindgren 3160 Series, User Manual

Page: 23 / 70

6.0 Radiated Emissions Measurements
Measure Ambient Field Strength Values
1.
Install the antenna where measured field strength values are desired.
2.
Adjust the desired orientation of the antenna for both bore site direction
and polarization.
3.
Connect the output connector of the antenna to the input of the
receiving system using a low VSWR, low loss coaxial cable. The
Model 3160 Series Pyramidal Horn Antennas are designed for
receiving systems having 50
Ω input impedance. Other values of
receiving system input impedance will require correction for the
difference in impedance mismatch.
4.
Set desired measurement frequency on the receiving system. Make
sure that the selected frequency is one that can be used with the
antenna that is connected to the system.
5.
Measure the RF voltage, V
a
, referenced to the input port of the
receiving system. The units of the measurement should be in decibels
referenced to 1 microvolt, dB(µV). If the units of measurements are
millivolts, they should be converted to dB(µV) by:
6.
Determine the field strength at the frequency of observation by adding
the voltage reading on the receiving system in dB(µV) to the
antenna factor in dB(m
-1
):
V RF voltage in microvolts
RF Voltage, dB(µV) + Antenna Factor, dB(m
-1
) =
Field Strength, dB(µV/m)
E
a
= V
a
+ AF
)
V V
a
a d
=
=
20
20
10
10
log (
log
Radiated Emissions Measurements |
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