Diversity Versus Non-diversity
Diversity wireless systems always out-perform otherwise similar non-diversity systems. However, despite the inherent advantages of diversity operation, many other aspects of equipment design are also very important. For this reason, it is not unusual to obtain more satisfactory results with a high-quality non-diversity system than with a poorly-designed or cheaply-made diversity system. This is especially likely in areas where interference is a serious problem.
A diversity system is highly desirable because it effectively combats the most common problem with wireless microphone equipment: signal dropouts due to multipath. Multipath occurs when RF signals arrive at a location via different transmission paths (usually referring to a combination of direct and reflected signals). Under these conditions, the audio output of the wireless receiver may become noisy, or the audio may be lost entirely for a short time. Multipath is most likely to occur in closed areas where many metal objects are present, but can occasionally be troublesome in most situations.
Diversity receivers are able to avoid dropouts due to multipath because they have two antennas and two receiver channels. Special circuits in the receiver select the audio from the antenna and receiver channel with the best signal. Because the chances that there will be simultaneous dropouts at both antennas are extremely low, diversity receivers provide almost complete immunity from dropouts due to multipath.
Diversity operation can also improve the useful operating range for wireless systems. This is because even when there are no actual total dropouts, multipath effects can reduce the amount of signal available at long ranges. This can cause the receiver to briefly lose audio well before the transmitter is truly out of range. With diversity, complete signal loss is much less likely and the useful operating range of the wireless system will be extended.
It is recommended that diversity equipment be purchased unless the budget simply will not accommodate the extra cost. However, the use of non-diversity equipment should not be rejected entirely. Despite its limitations, non-diversity equipment can provide satisfactory operation in many less-demanding applications, perhaps at the expense of some additional setup and checkout time.
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