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INSTRUCTION MANUAL
AM-741R
ACTIVE MONOPOLE 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
EXAMPLE:
We’ll use the measurement system shown in Figure 9, and assume a 1-
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 20 dB
μ
V.
For the system shown above, there are two (2) correction factors needed:
1)
The AM-741R
Active
Antenna Factor
2)
The Insertion Loss Factor for the cable connecting the AM-741R 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 Antenna Factor is -1.35 dB/m (
in practice, you will use your actual
calibrated factors rather than the typical factors).
Measured amplitude @ 30 MHz =
20 dB
μ
V
Active E-Field
Antenna Factor @ 30 MHz =
-1.35 dB/m
Insertion Loss of Coaxial Cable @ 30 MHz =
2 dB
Measured Amp Active Antenna Factor
+ Insertion Loss of Cable=
20.65 dB
μ
V/m
MIL-STD 461 Field Strength Limit @ 1 meter =
24 dB
μ
V/m
Limit
Δ
=
-3.35 dB
