Chameleon Antenna 40/20 FD | Fan Dipole first look

Hello Operators

Some weeks ago Chameleon Antenna sent over their 40/20 FD fan dipole for some testing. As you may know, Chameleon occasionally sends over equipment for testing in the harsh environment of 65° North. By sending these models up north, they get valuable feedback for product improvements, while we get honest testing and evaluation of the equipment. It’s a win-win for everyone.

Here’s what the Chameleons website says about the antenna.

The Fan Dipole antenna, is a High Frequency (HF) antenna designed to provide a field- tunable resonant portable antenna for two of the most popular amateur radio bands. This antenna will provide long-range communication on both the 7 and 14 MHz (40 and 20m) bands utilizing skywave propagation and short-range communication using Near Vertical Incidence Skywave (NVIS) propagation. Due to the antenna’s small size and rugged construction, it is ideal for temporary setup at a campsite or emergency shelter and durable enough for semi-permanent installation at a base station – even RV sites or dense suburban housing with small yards should be able to accommodate this antenna. Without an antenna tuner, the Fan Dipole can operate on the 40 and 20m amateur radio bands. A wide-range antenna tuner will also enable operation on the 17, 15, 12, and 10m bands.

Specifications:

• Frequency: 40M – 20M (NO TUNER) 17M, 15M, 12M & 10M with a wide-range antenna tuner.
• Power: 500W SSB or 250W CW
• Length: 33’ per leg for 40M and 17′ per leg for 20M of Copper Clad KEVLAR PTFE (Teflon) (-70°C to 150°C) wire
• Weight: 2.2 Lb.

The antenna system consists of:

• 1 X BALUN 1:1
• 2 X 33′ Copper Clad KEVLAR Wire (7 MHz)
• 2 X 17′ Copper Clad KEVLAR Wire (14 MHz)

My initial thought was wire, lots of wire! Of course, my experience with dipoles includes frostbite while trying to set them up (alone) in the middle of winter. I definitely didn’t come into this with any objectivity. After reading Chameleons website and understanding who the target customer is, I began to understand the point.

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Like all of Chameleon products, this one is built like a tank. You’re never going to break the wire, and you’re never going to break the balun enclosure. The kevlar-reinforced copper-clad wire is good down to -70C. Unlike that ridiculous SOTA wire which tangles and stretches like there’s no tomorrow, It won’t get brittle, it won’t get kinked, it won’t become a wire mess. Integrated winders make wire management simple. It’s a double-edged sword here since winders reduce frustration but add a little weight. Even so, the winders make deployment, tear-down and storage fast and easy.

We already know about Chameleons quality/component choices, so what about performance? Let’s see what performance looks like with JS8Call and FT8, running 20 watts through a Xiegu G90.

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Performance was what we would expect from a resonant dipole antenna. Even better if we consider the 40/20 FD is mounted at just 5 meters or 16.5 feet above the ground in an inverted- vee configuration. This was intentionally done to mimic an “easy” portable deployment. North America and Australia with 20 watts from the G90. The station is being heard by and hearing the stations spotting it on PSK reporter. We can’t ask for more than that!

SWR Plots

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SWR and return loss are excellent. I’m certain moving the balun away from the tower leg, will get them dialled in perfectly. For now, these results are A-OK.

Thoughts

No tuner required, maximum efficiency, easy deployment with a fibreglass military mast make this an attractive field or fixed station option for 40/20m. What would make it more attractive is optional pre-cut wire legs for other bands. Instead of 40/20 how about 60/40/20, 30/18/12, 60/30,..? The modular characteristics of Chameleon Antennas are one of their most attractive assets. It allows an operator to take CHA components, using them like lego blocks for a customised system. I see no reason why custom fan dipole combinations couldn’t be offered. For personal preparedness, an 80/40 or in my case 60/40 FD would be epic. 60 for Winlink (day/night). 40 for JS8Call.

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For the type of operating I do, a dipole would only make sense in a handful of deployment scenarios. An end-fed random wire, end fed half wave, end fed inverted-vee can all be more practical for man-portable deployment, but won’t perform as well as a dipole at height. This is a factor only when the operator must themselves carry the additional gear required to raise the dipole to height. If in a base camp scenario, car camping, overland camp, FOB, … where weight and support gear is carried in vehicles, the FD performance benefits would be welcome.

Tip: For portable work, I suggest adding 3mm stretch cord to the ends of the legs. Stretch cord is much easier to work with, while keeping tension on each leg in a variety of configurations.

With everything said so far, the FD will spend some time mounted on the tower. It will be role-playing as a “reference antenna”. A single antenna with which we judge all others. A reference antenna provides us with a baseline to use in “this vs that” antenna comparisons. It doesn’t matter too much what antenna it is, provided it has reasonable performance and efficiency. This is how the FD will be used for the channel and blog.

Have questions? Please leave thdm in the comments.

A huge thanks to Chameleon Antenna for sending the 40/20 FD over. As always, please support the organisations enabling the blog and channel to continue moving forward.

More info on the Chameleon 40/20 FD here

73
Julian oh8stn
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