How Maidenhead grid squares encode latitude and longitude — fields (AA-RR), squares (00-99), subsquares (aa-xx). Used by every ham operator for QSO exchange and beam-heading calculation.
Maidenhead is the worldwide grid-square system every ham operator uses to identify station location. It's a hierarchical alphanumeric encoding of latitude and longitude — short enough to say on the air, precise enough to point a directional antenna at.
Three nested levels of subdivision:
Six-character grids are the standard — short enough to exchange in a contest, precise enough that beam-heading lands within antenna lobe width. Four-character common in HF QSOs. Eight-character for very precise VHF/UHF / EME / contest work.
Part of the BloomWX learn library — beginner-friendly explainers covering every surface of the BloomWX weather dashboard. Open BloomWX to see live data for any U.S. county.