DV/IP™ repeaters utilize dual receivers which can provide both diversity reception on a single receive frequency, combination simplex/duplex reception, or reception on two separate receive frequencies. In systems that utilize "shared" channels, the second receiver may be used to monitor the transmit frequency for co-channel repeaters to comply with regulatory "monitoring" requirements.

The techniques of diversity reception are well known and have been in practical use for over fifty years. Diversity reception provides diverse signal paths to overcome deep signal fades that occur when a distant transmitter moves. Diversity reception also helps eliminate fade problems that can occur even with fixed systems, such as point to point microwave, when the characteristics of the path change due to weather conditions, even over short path separations. An extreme example of diversity reception are radio astronomy "large array" antenna "farms" where the antennae are separated by hundreds of meters or sometimes even thousands of kilometers.

DWC operates a communications test center at what was originally a Western Union microwave facility. That facility is instructive as it was once equipped with multiple microwave antennas on the same "path" and frequency separated by as more than 100 meters, to provide two separate diverse paths to the same distant fixed site. Fixed microwave engineers know that propagation between two separate but identical microwave systems between the two same sites can vary dramatically from moment to moment.

It is well known that in order to be effective, at minimum ten wavelength separation between diversity antennae must be maintained. In the early 1980's cellular and mobile radio manufacturers experimented with diversity reception in mobile radios that operated at 800 MHz. However, the difficulty in obtaining suitable separation, even at the short wavelength of 800 MHz, led to the eventual abandonment of the technique in mobile radios. In the bands below 800 MHz, with far greater wavelengths, the necessary diversity antenna separation would require far longer antenna separations than the length of vehicles permits, and therefore diversity reception in vehicles is not practical. If offered, it is mere showmanship. Moreover, since in the 21st Century almost every practical mobile radio system should be designed to support portable radios (where diversity reception is obviously impossible) diversity reception is only useful at fixed base station repeaters.

In analog and digital radio systems, almost universally the "talk out" (base station repeater to portable or mobile radio) capability vastly exceeds the "talk in" (portable or mobile radio to base station repeater), even with similar transmitter ERP [effective radiated power] levels at each end. More often, base station transmitter ERPs exceed portable or mobile ERPs, often by 10 dB or more. Consequently the coverage area of a mobile radio system is generally limited by the "talk in" range and most easily increased by improvements to the base station repeater receive system. In order to maximize "talk in" DWC's experience has led to low noise repeater receiver "front ends" using ultra low noise PHEMT amplifiers and well designed "high end" filtering and antenna systems. The use of diversity reception, while not mandatory, adds between 2 and 5 dB improvement to the "talk in".

A practical base station repeater diversity antenna system is described at the previous link for the DB-1000 base station repeater.