RF Calculators

Antenna design made simple Planning and cutting antenna wires often raises the same questions: how long should the dipole arms be?, what if I use insulated wire?, or how much do I need to trim if the resonance is off? This calculator helps you estimate the correct lengths for common amateur-radio antennas (dipoles, verticals, EFHW,…

An ugly balun (air-core coaxial choke) is a simple and effective way to suppress common-mode currents on the feedline of your HF antenna. It consists of several turns of coax wound tightly on a non-conductive form such as a PVC pipe or even a soda can. This calculator helps you quickly design your own ugly…