As you zoom out, you will start to loose labels as there will be too many for them all to read so RadarBox prevents overlap by hiding some of the labels.
If you zoom out further still, you will get to a point where RadarBox only displays a dot and the trail if selected. You have to zoom out a long way for this to happen though, see the screenshot below which covers the whole of the UK and some of NW Europe, if you zoom in one level, the labels reappear.
Below, zoomed in one level from the screenshot above.
Below: Here is the same picture posted at the top with the range rings switched on. RadarBox deosn't show the level of zoom, but the 4th range ring here is at 263.6 miles, giving 527 miles from edge to edge.
Below: If you zoom in until the labels appear, you can still can see out to 197 miles and the map shows 394 miles from edge to edge.
