What an azimuth map is
An azimuth map, often called an azimuthal or great circle map, is a world map drawn with your own station at the center. Instead of the usual rectangle, the globe is projected so that a straight line from the center to any other point shows the direction you would point an antenna to reach it. The common version used by hams is an azimuthal equidistant projection, in which distance from the center is also drawn to scale.
Azimuth itself just means a compass bearing, measured in degrees clockwise from north: 0 is north, 90 is east, 180 is south and 270 is west.
Why hams use one
On a normal flat map, the shortest path between two far-apart places is often not a straight line. A great circle route, which is the shortest path over the Earth’s surface, looks curved on many maps. An azimuth map centered on you makes those paths straight, so you can see at a glance:
- the beam heading toward a country or prefix you want to work,
- roughly how far away it is, and
- which parts of the world lie in the same direction, so one antenna heading covers several targets.
It is especially handy for HF DX, where you are often pointing a directional antenna at places thousands of kilometers away.
How to read it
- Find your station at the center of the map.
- Locate the place you want to contact.
- Read the bearing from the angle marked around the edge, measured clockwise from north.
- Estimate distance from the rings, if the map includes them.
Short path and long path: a signal can travel either way around the Earth. The long path heading is the opposite direction from the short path, so it differs by 180 degrees. Operators sometimes find stations more readily on the long path under certain conditions, so it is worth knowing both headings.
True north versus magnetic north
Maps like this are built on true north. A magnetic compass points to magnetic north, and the difference between the two, called declination, depends on where you are and changes slowly over time. If you set a beam by compass, you may need to correct for declination. Rotators with a calibrated heading indicator are normally set against true north, but it is worth checking your installation.
How to get a map for your station
You do not need to draw one by hand. Several options exist:
- Online generators: some web forms create an azimuthal map for any location. They typically accept latitude and longitude, a Maidenhead grid square such as IO91um, or a city name, and let you customize the radius and labels.
- Logging and DX software: many programs show a great circle map and bearing to any call sign or prefix you enter.
- Printed maps: some vendors sell wall maps made for a specific station location.
Whichever you use, enter your location as accurately as you can. A grid square is fine for rough work, but exact coordinates give better bearings.
Using it with a beam and rotator
If you have a directional antenna on a rotator, the map gives you the heading to send it to. A practical workflow:
- Identify the prefix of the station you hear. The call sign prefixes list can help.
- Look up the country and its location, see call signs by country.
- Read the heading from your azimuth map and set the rotator.
Many logging programs can do the lookup and drive the rotator automatically.
Limits of the map
A map shows geometry, not radio conditions. Propagation can bend or scatter signals so that the best direction is not always the great circle path. Antenna patterns also have finite width, so a heading that is a few degrees off may still work. Treat the map as a good starting point, and adjust by listening.
Related reading
- Ham radio regions and ITU zones to see how the world is divided for operating.
- US call area map for headings between US call areas.
- Ham radio call sign prefixes list for working out where a station is from.