Transforming a small copper coil into a large copper loop was easy with a home made jig.

Last week, I described using my CNC machine to mill a small jig to help fabricate my magnetic loop antenna. The jig is an 18” long piece of scrap lumber which contains a half-inch channel. This channel is a small arc of the right curvature for a five foot diameter loop. The jig is shown in the lower center of the picture. The original one-foot copper coil is shown in the top left and the final loop is lying on the garage floor.

Unwrapping this small 20’ coil of refrigerator tubing into a roughly 16’ loop with the five foot diameter was really easy using the jig. It took about five minutes. All that was needed was to carefully unwrap 18” of the coil into the jig’s channel, then move on to unwrap the next 18”, and so on, until the job was complete.

This copper loop will now be mounted on a piece of one inch PVC pipe.

Printing Copper Loop Mounting Brackets

As an alternative to cutting holes into the PVC pipe, I am currently 3D printing some mounting brackets to hold the loop in place. The top bracket will hold the two ends of the loop. This is where the capacitor will be attached. The top bracket will clamp onto the pipe, and around each end of copper tubing. The bottom bracket will simply be located one diameter away and hold the loop in place.

My project has been delayed with yet another hot end failure on my 3D printer. This time, rather than another cheap Chinese clone, I am buying a genuine E3D V6 hot end. It costs 3-4 times as much but my support group says the genuine hot ends are far less prone to failure.

In the meantime, I have moved on to designing my wireless remote control for the loop.