Tommy "SA2CLC" Stenmark's 3D-Printed Vertical Antenna Loading Coil Is Clever, Compact, and Multiband
Printed in around 22 hours, SA2CLC's PETG loading coil is good for hundreds of watts — and uses less material than earlier designs.
Radio ham Tommy "SA2CLC" Stenmark has published a build video for a multiband antenna loading coil that was designed in Autodesk Fusion 360 and printed on a consumer Creality Ender 3 printer.
"The coil form is printed in PETG at high resolution," SA2CLC explains. "I have designed the coil using Fusion 360, with inspiration from an OK1CDJ design if I remember correctly."
"I set up the antenna using a 6m fishing rod, [with] 2 radials, each 5m long. The radiator was cut to give good SWR at 20m with shorted coil, and then 30, 40 and also 60m could be matched using the coil."
Designed to adjust the inductance of an antenna, the loading coil is adjustable using an alligator clip which can be moved to increase or decrease the number of coil turns in use at any given time. Compared to earlier equivalents, SA2CLC's is printable using less material and takes up a smaller footprint — but its performance is equivalent.
The full video is available on SA2CLC's YouTube channel, but the design files have not yet been released.