A some of you may know, the AIM4170 antenna/impedance analyzer was introduced
recently. It retails for about 500 USD. More information is available at:
http://www.arraysolutions.com/Products/AIM4170.htm. It has been reviewed very
favorably in a number of places (see Web page for links).
I bought one and I am very impressed with it. It's a bit more money than the
popular hand-held analyzers, but for serious measurements, particularly outside
of the range of 50-75 ohms, it's far more accurate. I compared the AIM4170 to
the AEA VIA Bravo, which costs four times more, and the AIM is more accurate at
very low impedances (< 10 ohms) and very high impedances (> 1 kohm).
It does require a PC to run, making it less portable than the hand-held units.
However, it will run on batteries and with a laptop, you can take it out in the
field to make measurements.
The software interface is very intuitive and easy to use. Based on my
experience so far, it also appears to be bug-free. The interface provides
great flexibility in setting up the instrument (frequency range, frequency
resolution, overlaying of multiple traces, scaling of plots, etc.). Raw data
can be saved in the CSV format for post-analysis in MS Excel or other programs.
Immunity to RF overload appears to be quite good. I took the analyzer to a
friend's QTH for antenna measurements. He lives very close to a 50 KW AM BC
station. With a wideband scope we measured 0.4 V peak RF across the feedpoint
of the antenna from the BC station. However, we had no trouble making good
measurements from 160 to 10 meters. My friend's Autek analyzer completed
folded up in the presence of the same interference. The manual for the AIM4170
indicates 2 V peak is the "damage" threshold for the device.
Another feature, which I find very useful and important, is an automated
calibration procedure that compensates for the stray inductance/capacitance of
measurement leads. Those of you who have tried to make measurements of high
impedances at high frequencies can appreciate how important this is.
Disclaimer: I have no affiliation with or commercial interest in the vendor.
I am a very satisfied user and highly recommend this unit. It provides a lot
of performance at a very reasonable price.
73, John W1FV
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