Com-Power AHA-118 User Manual
Features
Frequency Range – 1 to 18 GHz
Increased Sensitivity with a Built in Preamp
Two-year Warranty
Individual Calibration
Active Horn Antenna
AHA-118
Description
The model AHA-118 Active Horn Antenna is basically
the AH-118 Horn Antenna with an integrated preamplier. The preamplier has a nominal gain of 20 dB for
the entire frequency range. The preamplier improves
the effective system noise performance for emissions
testing as explained below. The antenna AH-118 is linearly polarized and has a frequency range of 1-18 GHz.
The output of the antenna is connected to the preamplier by a short low loss cable, which can be removed.
This arrangement makes it possible to (1) insert a lter
before the amplier and (2) use the antenna alone for
transmission. The lter insertion capability is important and is required in presence of a high-level signal
(such as fundamental frequency), which possibly could
saturate the amplier if the lter is not used. The transmitted signal ow is in opposite direction and uses a
higher power level. Both conditions could damage the
preamplier if not removed.
This antenna is constructed using lightweight aluminum
with a corrosion resistant conductive coating. The
rear mounting plate of the AHA-118 has 1/4 inch x 20
threads. These threads allow the antenna to be mounted
on a model AT-100 antenna tripod or any tripod with
similar mounting arrangement. The antenna is powered
by an supplied external DC wall mount adapter.
Application
This antenna is suitable for accurately receiving low
amplitude radiated emission signals. It is used during
EMC testing for various standards such as FCC part
15, CISPR, and FAA for EMC emissions.
For obtaining valid data during the test, it is imperative to maintain signal level above the noise oor.
In a typical setup, a receiving antenna is connected
to a preamplier that is located next the spectrum
analyzer. The output of the preamplier is then fed to
the spectrum analyzer. In this arrangement, since the
location of the preamplier is far from the antenna,
the interconnecting cable is long. A combination of
factors such as a long cable, increasing cable loss
(especially for frequencies above 1 GHz), and high
antenna factors reduce the signal level to below the
noise oor of the preamplier; and that produces
invalid readings. Boosting the signal at the antenna,
prior to its attenuation by long cables keeps it from
falling below the noise oor.
Each antenna is individually calibrated. The correction
factors and certicate of calibration is shipped with
the antenna. The data also includes separate antenna
factors and amplier gain.
Com-Power Corporation (714) 528-8800 www. com-power.com sales@com-power.com
Specications
Frequency Range: 1 GHz - 18 GHz
Bulit-in preamp gain: 25 dB ± 2
Output VSWR: 2.5 :1
Polarization: Linear
Output Impedance: 50 Ω
Connector types
Antenna output: N (f)
Preamplier input: N (f)
Preamplier output: N (f)
Power input: 18 VDC, 500 mA
Weight: 7 lbs. (3.1 kg)
Size: 10.2" X 9.5" X 5.6" (25.9 cm x 24.1 cm x 14.2 cm)
Mechanical outline
Antenna output to preamplier input side view
Tripod
Mounting
Block
Preamplier
Housing
Preamplier input
Typical Antenna Factors
Model AHA-118
30.0
20.0
Antenna output
10.2"
Preamplifer output side view
Tripod
Mounting
Block
Preamplier
Housing
Front View
9.5"
10.2"
Preamplier output
5.6"
10.0
dB/m
0.0
-10.0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
GHz
All values are typical values unless specied.
All specifactions are subject to change without notice.
Com-Power Corporation 114 Olinda Drive, Brea, California 92823 (714) 528 - 8800 www.com-power.com
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