Wireless Microphones - The Basics


  • Every wireless microphone system must operate on a specific frequency.

  • The government dictates which frequency ranges can be used by wireless.

  • Wireless frequencies are shared with TV stations, communications equipment and a large number of wireless microphone systems.

  • Because of frequency sharing, there is always at least a small chance that someone else in the area might be using the same frequency as your wireless system.

  • Government regulations also set strict technical requirements for wireless, including limits on maximum transmitter power.

  • There must be one transmitter and one receiver to make a complete wireless system, and they both must be on the same frequency.

  • If any two transmitters are operating on the same frequency, severe interference will result and the wireless system will be unusable. Two transmitters cannot be used with one receiver at the same time.

  • If the frequencies of any two wireless systems are too close together, interference is likely, and one or both systems will probably be unusable.

  • The practical maximum operating range of a wireless system will vary from as little as 100 feet (30 m) in heavily crowded indoor situations to approximately 1,000 feet (300 m) under open outdoor conditions.

  • Diversity wireless systems will almost always have better operating range than similar non-diversity systems.

  • Wireless receivers must have either one or two external antennas, and there should be a clear open-air path between these antennas and the transmitter.

  • Weak or worn-out transmitter batteries are a common cause of wireless problems, including complete failure, poor range, distorted audio and interference.

  • Use only high-quality alkaline batteries. Most other types of batteries will have much shorter life, and some may cause other problems.

  • Because it is easier to accidentally walk near speakers, feedback problems are slightly more common with wireless microphones than with wired microphones.

  • The power output of wireless microphone transmitters is very low, and they are completely safe to use. However, any source of RF energy may interfere with the normal functioning of implanted cardiac pacemakers or AICD devices. A body-pack transmitter should not be worn where it is immediately adjacent to such a medical device. Note also that any medical-device disruption will cease when the RF transmitting source is turned off.

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