LoginThis is the new magic carpet! Faraday cloth ground network
I’ve been using this window screen as a ground network for six months now. Is there something better out there? My viewers say there is, so meet the new magic carpet: Faraday cloth.
Faraday Fabric, 108×44 inches (3 yards): https://amzn.to/3RTjDv7
Window Screen Antenna Ground Plane: Video: https://youtu.be/UadUg5H8KO8
(This is the video that started the whole ground screen revolution).
About six months ago, Dave KZ9V and I demonstrated how a simple piece of aluminum window screen can be used as an effective ground network for a vertical antenna. The screen offers similar performance as conventional ground mounted wire radials, but it has the advantage of being easier to deploy and taking up less space than wires. Suffice to say, the concept has pretty much taken the amateur radio portable operation world by storm. Countless hams have tested the window screen and it’s working for them.
The downside of window screen is that it can be hard to roll out, it’s a bit stiff, and when rolled up it takes up more physical space in the back of your vehicle. Wouldn’t it be great if there was a material that was flexible, lightweight, and folds up into a tiny package.
But I love it when someone takes an idea and finds a way to make it better. And recently I’ve started seeing many hams that are into portable operations using a new material as their ground network. This material is lightweight, folds into a small package and offers equivalent performance as a window screen. This magical material is known as faraday cloth.
What is faraday cloth? Faraday cloth, also known as faraday fabric or EMP fabric, is a conductive fabric material with strands of copper, silver, and nickel threads woven into it. The purpose of this cloth is to block electrical charges and EMF or electromagnetic frequency radiation. It works on the principle of the Faraday Cage.
Michael Faraday was a 19th century scientist dabbling in electricity and electromagnetism. He discovered that static electricity resided only on the exterior of a charged conductor and had no influence on the interior of the conductor. This shielding effect led to the invention of the Faraday cage, a metal screened structure that blocks electromagnetic radiation and radio frequency radiation.
This cloth uses the same concept, with metal threads, it creates an impervious surface to electromagnetic radiation. EMF sensitive objects wrapped or sealed within the cloth should be protected by RF radiation like an electromagnetic pulse. I’m not going to question the effectiveness of the cloth in that regard as that’s not the topic of this video.
But the one thing the cloth is good at is being used as a conductor. Running a continuity tester across the cloth, you see it is a conductor, and it presents a minimal amount of impedance. That means it could be used in the same manner as a window screen as a ground network for your vertical antennas.
To verify that, I spread out the cloth, set my antenna base on it, and deployed my vertical antenna. I’ll also check the SWR, impedance, and resonance for the 15, 20, and 40 meter bands.
But there is a downside to the cloth. It is significantly more expensive than aluminum window screen. My 36×84 inch roll of screen was under $10 and this 43×108 inch piece of cloth is about $32. Granted you get a little more material, but that’s three times the price. The cloth, being lightweight, tends to blow around in the wind. You may want to add grommets to the corners to stake it down, or have some weights ready to keep it blowing away.
Finally, I did some WSPR tests comparing wire radials, aluminum screen, and faraday cloth. Crunching the numbers, I found the differences between the three to be minimal and all within the margin of error. WSPR tests seem to confirm that you won’t be losing any performance between conventional wire radials and the faraday cloth. I think that’s great news, but how does it perform on the air? For that, I took a road trip to my favorite POTA spot and put the faraday cloth on the air.
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My Vertical Antenna Setup:
Feather Flag Base: https://amzn.to/3MdepHE
Wolf River Coils: https://www.wolfrivercoils.com/
MFJ-1979 whip: https://amzn.to/3B9cehF
Chameleon SS-17 Whip: https://chameleonantenna.com/shop-here/ols/products/cha-ss17
Jaw Mount Antenna Clamp: https://amzn.to/3VL5Ir6
SO-239 stud mount for jaw clamp: https://amzn.to/3VT1KwG
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