Amateur Radio as a hobby has a long history of encouraging experimentation using whatever one might have on hand. When [Tom Essenpreis] wanted to use his 14 MHz antenna outside of its designed ...

Inductors are not the most common component these days and variable ones seem even less common. However, with a ferrite rod and some 3D printing, [drjaynes] shows how to make your own variable ...

Designed for use in variable-frequency aircraft systems, a line of single- and three-phase transformers suit systems operating from 360 to 900 Hz. The transformers use special core materials to ...