A microwave network can be established from one end of the country to the other. MCI and AT&T established such networks, but that of course involved a multitude of repeaters. So then we'll talk about the practical distance limitation for a single point-to-point microwave connection.

We've heard of a seventy mile microwave shot to an observatory in Arizona, but unless you're in an arid climate and shooting to a mountain that's visible at such a distance, the practical limitation is about forty miles. Believe it or not, the problem becomes earth curvature and so at longer distances you need to have massive towers, six hundred feet high or more.

Other limitations are sometimes confused with microwave, but in fact they have to do with the application rather than with microwave technology. For instance, a native half-duplex 10 megabit Ethernet connection is limited to about four and a half miles, but that has to do with allowable propagation delay in the 802.3 Ethernet spec. By converting to full duplex Ethernet however, you can go as far as the radio signal will take you.