Imax 2000 EXPOSED!
Have you ever wondered what was inside the Imax 2000 antenna?
After dissecting the Antron 99 antenna and discovering that its advertising claims were horribly over-exaggerated, I became curious about other fiberglass 'wonder' antennas. An opportunity to dissect the Imax 2000 presented itself, so I accepted.
The first thing you notice about the Imax 2000 is that it is LONG! I measured the copper wire elements after they were removed from their fiberglass radomes:
Bottom section: 80
Middle section: 94 inches
Top section: 96.5 inches
That makes the total radiating element length 270.5 inches. Using 27 MHz. (CB) as center frequency (which this antenna was designed for), that makes the Imax 2000 a 0.640 wavelength antenna. (A 5/8 wave antenna is 0.625 of one wavelength). I was very surprised to find that the Imax 2000 is not a 5/8 wave as advertised. The Imax 2000 is actually a .64 wave! The .64 wave is one of the best kept secrets in CB and 10 meter antennas. Not since the Super Penetrator 500 Gold has there been a .64 wave antenna widely available. A .64 wave antenna is the highest gain single element design there is with 0.4 dB more gain on the horizon (free space) than a 5/8 wave element.
So what is
the TRUE gain of the Imax 2000? Assuming a .64 wave shunt
fed dipole in free space, minus the losses associated
with the series capacitance and inductance, and minus the
necessary counterpoise, according to my math, the Imax
2000 has 2.9 dBi gain. That is to say, the Imax 2000 has
2.9 dB gain on the horizon over an isotropic radiator.
Referenced to a center fed 1/2 wave dipole, which is the
industry standard, the Imax 2000 has a gain of 0.8 dB.
This could also be stated as 0.8 dBd gain. Although
adding the Antron GPK-1 ground plane kit will not add
much gain to the Antron 99, the ground plane kit would
add significant gain on the horizon for the Imax 2000. A
.64 wavelength radiator is much more efficient and will
have a much lower angle of radiation (keep the signal
down on the horizon instead if wasting it up in the sky)
with a proper counterpoise system. Adding the GPK-1 to
the Imax 2000 (according to my math and previous .64
wavelength test range plots) will result in a 0.3 dB gain
improvement. This will bring the Imax 2000's actual gain
up to 3.2 dBi (or 1.1 dBd).
complete report of the Imax 2000 on the antenna test
range compared with and without the ground plane kit
added, click on the plot or HERE .
CONCLUSION: The Imax 2000 will easily outperform the Antron 99 and other 1/2 wave antennas like the popular 'Ringo'. Adding the GPK-1 ground plane kit will provide a significant improvement in gain on the horizon, which will noticeably improve local communications. With the wide availability and reasonable price of the Imax 2000, it is easy to suggest this antenna to the 10 and 11 meter enthusiast who desires top performance, and a more visually low profile fiberglass antenna.
Thanks: Special thanks to Copper Electronics ( www.copper.com ) for graciously providing the antenna for this review.
Interested in the Solarcon A99? See: The Antron 99 EXPOSED!
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About the author:
The author is a professional broadcast engineer with over 20 years experience in the design, maintenance, and construction of broadcast transmitter and studio facilities. He has experience with high power antenna installations and has been involved with simple single antenna installations to complex phasing and directional arrays. The author is currently a successful contract engineer in California and has become highly respected and well known in the industry.