AMRT Amateur Radio RF Toolkit

Antenna lengths, VSWR, coax loss, Smith chart, resistor codes & Maidenhead grid — 26 amateur-radio calculators and references, all fully offline.

Your amateur-radio bench, in your pocket — and it works completely offline.

AMRT brings the calculators and references hams reach for most into one fast, ad-free app. From cutting a dipole in the field to checking SWR in the shack, every answer shows the formula and assumptions behind it.

ANTENNAS • Dipole, inverted-V, end-fed half-wave, vertical, J-pole, Yagi, cubical quad, full-wave loop & small magnetic loop • Lengths in metres, feet or fractional inches, with cut lists and diagrams

RF & FEEDLINE • VSWR, return loss & mismatch loss • Coax cable loss and power at the antenna • Smith chart impedance matching • dB to power/voltage

ELECTRONICS • Ohm's law, reactance, LC resonance, voltage divider • Series / parallel networks • Resistor, capacitor & SMD codes, AWG wire gauge

LOCATION • Maidenhead grid square, distance & bearing • Look up your grid from GPS

REFERENCE • Q-codes, RST, NATO phonetic alphabet, Morse, band plans

MORE • Save calculations into projects and share results instantly • Home-screen widget: your callsign, home grid & UTC clock • Imperial and metric units throughout

100% offline. No account. No ads. Just the tools.

Free to use the Dipole calculator — unlock every tool with a single one-time PRO purchase. No subscription.

73!