How much distance can there be, in miles, between the antennas at each end of a link?
A. Unfortunately, this common question does not have a quick or simple answer. Here are the factors that govern the maximum link distance: • Maximum available transmit power. • Receiver sensitivity. • Availability of an unobstructed path for the radio signal. • Maximum available gain for the antenna(s). • System losses (such as loss through coax cable runs, connectors, and so forth). • Desired reliability level (availability) of link. Some product literature or application tables quote figures, such as “20 miles.” In general, these quoted single values are optimum, with all of the above variables optimized. Also, remember that the availability requirement has a drastic affect on the maximum range. That is, the link distance can perhaps be double, or more, than the quoted value if you are willing to accept consistently higher error rates, which can be appropriate in an example where you use the link only for digitized voice applications. The best way to get a useful answer is to do a ph
