Locator · Distance · Beam heading
Grid square & beam heading
Enter a grid square, coordinates or a US callsign, or use your phone's GPS. Add a second station to get distance and the heading to point your beam, both short path and long path.
From
Path
Map
How it works
Grid squares use the Maidenhead Locator System adopted by the IARU: an 18×18 grid of fields (20°×10°), each split into 10×10 squares (2°×1°), then 24×24 subsquares (5′×2.5′), then 10×10 extended squares.
Distance and short-path heading are computed on the WGS-84 ellipsoid with Vincenty's inverse formula, accurate to well under a metre. Long path is the reciprocal heading, with the distance computed on a spherical Earth (mean radius 6,371.0088 km). Headings are degrees from true north, so correct for your local magnetic declination if you're aiming with a compass (magnetic heading = true heading − east declination).
Callsign lookups use FCC license data from callook.info. The location is geocoded from the license's mailing address, so it may not be where the station actually is.
- T. Vincenty, “Direct and inverse solutions of geodesics on the ellipsoid…”, Survey Review 23(176), 1975.
- WGS-84: a = 6,378,137 m, f = 1/298.257223563 (NGA TR8350.2).