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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
●
(9 49) 459 -96 00
●
co m-p o wer. com
REV112216
EXAMPLE:
We’ll use the measurement system shown in Figure 9, and assume a 3-
meter separation distance between the source and the antenna. We
observe a signal at 30 MHz using the spectrum analyzer, and its
[uncorrected] amplitude is exactly 38 dB
μ
V.
For the system shown above, there are three (3) correction factors
needed:
1)
The AL-130R
Active E-Field
Antenna Factor
2)
The AL-130R Active H-Field Antenna Factor
3)
The Insertion Loss Factor for the long cable connecting the AL-130R
to the measuring instrument.
We’ll assume that the insertion loss of the cable at 30 MHz is 2 dB. And, by
referring to the typical antenna factor tables in Section 8, we see that the
Active E-Field Factor is 12.58 dB/m and the Active H-Field Factor is -38.92
dB
Ω
/m (
in practice, you will use your actual calibrated factors rather than
the typical factors).
E-Field calculations:
Measured amplitude @ 30 MHz,
with a 3-meter separation distance =
38 dB
μ
V
Active E-Field
Antenna Factor @ 30 MHz =
12.58 dB/m
Insertion Loss of Long Coaxial Cable @ 30 MHz =
2 dB
=
52.58 dB
μ
V/m
@ 3 meters
Distance factor (30 meters to 3 meters) =
40 dB
Equivalent E-Field Strength @ 30 meters =
12.58 dBuV/m
FCC Part 15 Field Strength Limit @ 30 meters =
29.5 dB
μ
V/m
Limit
Δ
(margin) =
-16.92 dB
And, the H-Field calculations:
Measured amplitude @ 30 MHz,
with a 3-meter separation distance =
38 dB
μ
V
Active H-Field
Antenna Factor @ 30 MHz =
-38.92 dB
Ω
/m
Insertion Loss of Long Coaxial Cable @ 30 MHz =
2 dB
=
1.08 dB
μ
A/m
@ 3 meters
CISPR 11 H-Field Strength Limit @ 3 meters =
3 dB
μ
A/m
Limit
Δ
(margin) =
-1.92 dB
H-Field
Strength
(dBμA/m)
=
Measured Voltage
(dBμV)
+
Active H-Field
Antenna Factor
(dB
Ω/m)
Cable Loss
(dB)
+
E-Field
Strength
(dBμV/m)
=
Measured Voltage
(dBμV)
+
Active E-Field
Antenna Factor
(dB/m)
+
Cable Loss
(dB)
