Radius Mapping

As I was working with Charlie Mike-01 on the air, we were discussing the properties of NVIS (Near Vertical Incidence Skywave), and that theoretical 300 mile radius one can expect to reach. This led to my curiosity, and a bit of research, to seek out a program that would allow for radius mapping. That is, how can I get a visual map showing a radius around any given point – Something quick and simple to use, without having to download programs, plug-ins, apps, etc. Google doesn’t have such a feature, but someone in England developed a program and a web page which integrates with Google maps.

The following website will do exactly what we need for quickly determining and displaying radiant distances on a map. Go to the following website and bookmark it:


The developer apparently lives in England, so the map automatically defaults to London each time you open the web page.

Step 1 – Type in the city and state you wish to display at the center of your radius. For this example we’ll use Bozeman, Montana.

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Step 2 – Enter the distance of the radius. In this example, we’ll use the theoretically ideal maximum NVIS range of 300 miles.

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Step 3 – LEFT click your mouse at the exact point you wish to place the center of your radius. The radius (circle) will turn blue. In this example, the entire map turns blue due to our 300 mile radius, and the close zoom of our example city of Bozeman. Zoom out.

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There is your 300 mile radius. If you RIGHT click your mouse, the radius will disappear. The program will place a radius wherever you place your pointer and LEFT click.

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It will also overlay subsequent radiuses. For example, if you wish to see what a 100 mile radius would look like, in contrast to your 300 mile radius, simply type a new distance in the lower left-hand corner box and LEFT click your mouse where you would like the new radius to appear.

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A fun and simple tool. Hope you find it useful.