Hello,
Technically, this is doable as a bubble plot--with a few caveats. Maybe someone will chime in with an easier way that I don't know about.
1) You will need to select geodesic scaling on your axes.
2) Because bubble "sizes" reflect areas and not radii, you need to use the squared radius as the size variable.
3) Since bubble plot bubbles do not change size when you drag axes, zoom, etc., you will need to "calibrate" by using the slider.
In the first screenshot below, we're all set up, but uncalibrated. I know that it is a distance of 120 miles from the center of the circle to the pink dot on the border of Pennsylvania, a little northeast of Scranton. This dot represents the data in row 2, which is included only for the purpose of calibration. You can place the calibration point anywhere you want on the circumference of one of your stations' signal footprint. If you use a radius of 0 for the calibration point, its bubble will remain a dot, regardless of scaling.
In the second screenshot, I've increased the bubble size until the bubble just touches the calibration point. At this point, all bubbles for the stations in rows 3+ should accurately reflect the range of their signals, provided station 1's bubble touches the calibration point and you've used the square of the radius as the sizing variable.
If you are willing to live with the inconvenience of re-calibrating when you change the graph axes, this approach lets you avoid scripting.
For more flexibility, go the route Jim recommends. You'll have to do some spherical trig to convert degrees to miles in your specific part of the globe, and learn how to work with graphics objects.