Amateur Radio Calculators

Amateur radio planning questions sit at the intersection of RF theory and real-world station compromises. A dipole that is perfect on paper still needs end-effect correction and a practical feed arrangement. A vertical that measures resonant on an analyser still needs a workable radial system to achieve a low-angle radiation pattern. A portable POTA setup has to balance feedline loss, battery capacity, panel wattage, and the weight you are willing to carry to the summit.

This collection of 50 calculators is built around those real decisions. The antenna tools cover the most common HF and VHF designs — from a basic half-wave dipole to a multi-element Yagi — with formulas that account for velocity factor, end effects, and feed-point impedance. The propagation section moves from ionospheric MUF estimation down to line-of-sight geometry, so you can reason about both long-path DX on 20 metres and a local repeater link on 440 MHz.

The operating tools are aimed at the practical day-to-day needs that are easy to overlook: knowing exactly what repeater input frequency to program, whether your gray-line window is open for that rare DX entity, how many watts of solar panel you need for a three-day POTA expedition, or how many correct answers you still have in your budget during an Extra Class exam session. The contest scoring tools cover ARRL Field Day, CQ World Wide, CQ WPX, ARRL DX, ARRL Sweepstakes, and VHF grid-square contests with the correct per-mode QSO point multipliers.

All calculations run entirely in your browser — no data is sent to a server, no account is required, and results appear instantly. The formulas follow ARRL Handbook conventions, ITU-R recommendations where applicable, and the FCC Part 97 band plan for US amateur allocations.