Maidenhead locator, distance and direction

An area rather than an address

The MaidenheadMaidenhead locator×The Maidenhead system divides Earth into labelled geographic cells. Additional characters refine the cell; a locator identifies an area rather than an exact address.Example & full explanation → system divides Earth into grid areas. The first two letters identify a large field and two digits subdivide it. A four-character locator spans two degrees longitude and one degree latitude. Two additional letters subdivide that area into 24 steps in each direction. JN47db therefore describes an area, not an exact antenna location.

The first letters run from A to R; the final letters of a six-character locator run from A to X. Letter case does not change the meaning. The tool accepts four or six characters and uses the corresponding grid centre. The actual position within that area can differ.

The shorter path on a sphere

Distance is calculated as a great circle using a mean Earth radius of 6371.0088 km. This is a useful approximation between grid centres. It is neither road distance nor a survey-grade ellipsoidal distance. With large grid areas, the choice of centre already introduces noticeable uncertainty.

The displayed bearing is initial, measured clockwise from geographic north. Direction generally changes along a great circle. Magnetic declination is not included. Identical or exactly antipodal points do not have a unique initial direction in this model.

A map is not a radio path

The map shows the two calculated grid centres. That does not imply clear line of sight or a working radio link. Mountains, antennas, mode and propagation conditions are absent from the distance calculation. Use locators for orientation and documentation, then add an appropriate path model for a particular link.