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INSTRUCTION MANUAL
AL-130R
ACTIVE LOOP ANTENNA
1912 1 E l T o ro R d
●
Si l vera do, Ca lifo rni a 9 26 76
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(9 49) 459 -96 00
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co m-p o wer. com
REV112216
4.1 Antenna
Factors
Your AL-130R Active Loop Antenna is provided with two sets of active antenna
factors; Electric Field (E-field) Factors and Magnetic Field (H-Field) Factors. The
relationship between E-field and H-Field is given below.
Determining which factor is to be used will depend on the measurement units
used to define the specification limit.
If the limit is expressed in terms of magnetic field (Amps per meter), then the
magnetic (H-Field) factors should be used.
If the limit is expressed in terms of electric field (Volts per meter), then the electric
(E-Field) factors should be used.
In either case (E or H-Field), the factor is added to the measured value in order to
convert, or correct your measured value.
4.2 Preamplifier
Gain
Factors
Our second category of correction factors are gain factors for preamplifiers.
Preamplifiers are used to increase measurement sensitivity by increasing signal to
noise ratio. This is necessary when measuring low signal levels which would
otherwise be buried below the inherent noise floor of the measuring instrument,
typically a spectrum analyzer or EMI receiver. Ideally, input signals levels are
increased proportionate to the preamp’s gain, without significantly increasing the
overall system noise level.
The AL-130R is an Active Loop Antenna, and contains an internal preamplifier, so
additional signal amplification should not be needed. Additionally, the
preamplifier gain values are included in either factor set, so no additional
measurement correction is necessary.
E-Field
Strength
(dBμV/m)
=
Measured Voltage
(dBμV)
+
Active E-Field Antenna Factor
[dB(m
-1
)]
ELECTRIC FIELD EQUATIONS
(
VOLTS
per meter)
=
[H-Field]
Strength (A/m)
x
377Ω
V/m
=
[H-Field]
Strength (dBA/m)
+
51.5
dBV/m
=
Current (dBA)
[E-Field]
Factor
+
51.5 dB
dBV/m
=
Current (dBA)
[H-Field]
Factor
dBV/m
=
Voltage (dBV)
+
[E-Field]
Factor
dBV/m
MAGNETIC FIELD EQUATIONS
(
AMPS
per meter)
=
[E-Field]
Strength (V/m)
377Ω
A/m
=
Voltage (dBV)
+
[E-Field]
Factor
51.5
dBA/m
=
[E-Field]
Strength (dBV/m)
51.5
dBA/m
=
Voltage (dBV)
+
[H-Field]
Factor
dBA/m
H-Field
Strength
(dBμA/m)
=
Measured Voltage
(dBμV)
+
Active H-Field Antenna Factor
[dB(Ω/m)]
=
H-Field
(magnetic field)
51.5
dB
Ω
(Log [ 377Ω ])
-1
E-Field
(electric field)
=
377
Ω
(20*Log[51.5 dBΩ])
H-Field
(magnetic field)
E-Field
(electric field)
...or, in linear terms:
