Microphones: Selecting The Right Wireless System

by Audio-Technica

Both VHF and UFH wireless systems work very well today. Selecting the right wireless for your needs is not complicated. Simply apply the following information to your application.

Overview - The mistaken idea that UHF wireless systems somehow have overwhelming inherent advantages over VHF systems is widespread. However, the facts simply do not support this notion. As is the case with many technical issues, there are both advantages and disadvantages to UHF, as there are for VHF.

There are a number of important factors to consider. These include where the systems will be used, how they will be used, and for what purpose or application. Cost is always a concern and invariably plays at least some part in the final decision. Other factors, such as whether the equipment will be used in many different cities, may also be important.

The primary advantage of UHF (like Audio-Technica'a 7000 Series) operation is that there is less chance of interference. One of the more common problems with wireless operation is interference between wireless systems. Since there are considerably fewer UHF wireless systems in use at present, the chances of this type of interference are reduced. However, this problem can easily be avoided in VHF (like Audio-Technica's 1100 Series) systems simply by properly selecting operating frequencies.

UHF wireless systems always cost more than similar VHF wireless systems. The extra cost of UHF equipment is due to the necessity of using more expensive ultra-high-frequency parts, the greater total number of parts required and the need for more expensive construction techniques. Other manufacturing costs are also higher, especially the amount of time required to adjust the equipment and verify its performance.

There are many more equipment choices at VHF than at UHF, helping hold down prices and making it more likely that a system with just the right combination of features, performance and price will be available. Battery life for VHF wireless transmitters is almost always better than for similar UHF units; over the life of a system the savings in battery costs can be very significant. For larger wireless installations, the cost of antennas, cables, antenna splitters and preamplifiers is usually much less for VHF systems and performance is generally better.

As can be seen, cost considerations tend favor the use of VHF systems, while UHF systems are less likely to suffer interference. However, there are several other applications issues that can affect the choice:

Whether the choice is UHF or VHF, diversity systems are highly recommended. Diversity is especially valuable for UHF systems because dropouts due to multipath are more troublesome at UHF frequencies.

If the wireless equipment will not be used in a large city, interference is relatively unlikely, and VHF systems can be expected to perform very well.

If the wireless equipment will be operated in a major city, or in a heavy industrial area, UHF might be a better choice due to possible interference at VHF. However, entirely satisfactory VHF operation can still be achieved if frequencies are carefully selected.

If the wireless equipment will be used in different cities, VHF systems operating on the special frequencies in the 169-172 MHz range will be a good economical choice. However, these frequencies, which are sometimes referred to as "traveling frequencies," are very popular, and are not a good choice for situations where large numbers of wireless systems are likely to be present, such as at trade shows and expositions.

If the wireless equipment will be used in situations where several other wireless systems are likely to be present, UHF systems are recommended. This is because more frequencies are available and fewer UHF systems are in use, reducing the chances of interference.

In summary, there are a great many situations where VHF systems will provide excellent performance at substantially lower prices than for comparable UHF systems. However, there are certain situations, such as when interference is likely to be a significant problem, where UHF systems are the logical choice. Obviously, not all situations have been covered and there may be complications of one sort or another, or other factors that must be considered. If you are still unsure regarding the best choice for your particular application, please contact the audio specialists at Lentine's Music for further assistance.