With aluminum core PEX, we have created a mostly plastic wideband receiving loop that should survive Calgary’s weather extremes. Only time will tell how well it holds up.
So, I have finally moved my prototype wideband loop out of the basement and into the back yard. After painting it dolphin gray, it looks like an aluminum loop. But it’s not. The entire structure is made of plastic, except for the amplifier and a few stainless steel mounting bolts.
As described previously, I made this one meter diameter loop using half-inch aluminum core PEX. Commonly used for in-ground heating, this lightweight pipe is made with two layers of high density polyethylene covering a thin aluminum tube. I found PEX very easy to work with, especially shaping. And it holds its shape well. Your end result is equivalent to using half-inch aluminum pipe for building a loop antenna, although a lot simpler.
You can see the vertical brace in the middle, made of half-inch PVC. The PEX loop weighs about 0.7 pounds, while the vertical brace adds another 0.5 pounds. So, your total weight for this loop is 1.2 pounds, about 60% of the similar sized Wellbrook 1530.
At the bottom, I 3D printed a combined loop amplifier enclosure and lower brace using PLA plastic. My mounting pipe is a three foot length of 1½ inch ABS from Home Depot.
Thus, when I call this a Mostly Plastic Wideband Receiving Loop, I am not joking. Obviously the aluminum core in the PEX and amplifier are needed for this to be a real antenna. But otherwise, plastic all the way.
Mostly Plastic Wideband Receiving Loop Looks Nice, Too
I thought the dolphin gray paint would help the antenna blend in, and disguise the fact it is made from plastic and not aluminum. Besides, the aluminum core PEX is orange. In a future article I will describe the challenges of painting plastic.
My next step is to run 30 meters of CAT 7 outside to the antenna and fire it up. Hopefully it will work even better outside than it has in my basement. Once that is accomplished, I will build my DIY rotator. The motors should arrive from China next week.
Although lightweight, I am still a bit concerned about balance and wind loading for this loop, especially since I am using friction fit for the mounting components. One of the advantages of using plastic is to minimize the amount of metal close to the loop.