QTH locator calculator
Online Maidenhead QTH locator converter: coordinates ↔ locator up to 10 characters, the centre and bounds of the cell, and the eight neighbouring squares.
Great-circle bearing and distance calculator
Online calculator of bearing and distance between two locators or coordinates: short and long path, forward and reverse bearing.
Radio link budget calculator
Online link budget calculator: EIRP, free-space loss, the level at the receiver input and the margin above sensitivity.
Urban path loss calculator: Hata and COST-231
Online path loss calculator using the Okumura–Hata and COST-231 models: urban, suburban and open terrain, with a check on the range of validity.
Two-ray model and breakpoint calculator
Online two-ray propagation calculator: the breakpoint, the loss beyond it, the path difference between the rays, and a table of loss against distance.
MUF and hop length calculator
Online calculator of the maximum usable frequency from foF2: the secant factor, the working frequency, the number of hops and the longest single hop.
Satellite link parameters calculator
Online satellite calculator: orbital velocity, period, slant range, footprint radius and Doppler shift across the amateur bands.
Sunrise, sunset and grey line calculator
Online sunrise and sunset calculator from a locator or coordinates: times in UTC and local, the grey-line windows, solar declination and the equation of time.
Fresnel zone calculator
Online Fresnel zone calculator for the radius of the first Fresnel zone, for planning radio links and wireless networks.
Line-of-sight range calculator
Online radio horizon calculator — line-of-sight range between antennas with refraction taken into account.
Point-to-point radio link calculator
Online link budget calculator — the maximum range of a Wi-Fi link from power, antenna gain and receiver sensitivity.