toroid wound

Balun 1:1 - 1:1 Ruthroff voltage balun using a T200-2 Toroid core

How to Build a UN-UN - Building a 1:1 balun, aka un-un, with an Amidon Ferrite toroid core T 200

Air Wound 4:1 Balun - Do you want to build a high grade, very useable 4:1 Balun for less than a fiver, if the answer is YES, then this project is for you.

Balun 4:1 - 4:1 Ruthroff voltage balun design using a T200-2 Toroid core

Coil32 Priority listing - Coil32 is a free coil inductance calculator, that allows to calculate: single layer and multi layer air core coils, toroidal air core coils, inductors on ferrite rings, in pot core, flat coils on the PCB, and also LC resonance parameters. The program have additional plugins to calculate another kinds of coils. The application is free for usage and distributing.