RF Wireless Microphone "Rules of Thumb": System Planning and Operation

• Always use fresh, fully charged batteries.

• Never operate two transmitters on the same frequency at the same time in the same location.

• Especially for initial planning, use software tools for frequency selection and frequency coordination, such as Sennheiser's Frequency Finder and SIFM respectively.

• Do not use equal frequency (equidistant) spacings for >2 channel. For example, if one mic system is set to 500 MHz and a second is set to 501 MHz (1 MHz apart from each other), a third mic should not be 499 MHz or 502 MHz. 502.200 would be OK because it is 1.2 MHz away.

• Use the scan function to find pre-coordinated frequencies that are clear at the location where the system will be used.

• After initial system set up, conduct a walk test throughout the performance area. Detune the antenna by putting your hand over it, touching it to your skin, or bending it to touch the body of a metal transmitter. This simulates a worst case scenario. For safest operation, the RF field strength at the antenna should be above 100µV throughout the test. For Evolution Wireless this corresponds to all 8 segments lit on the RF indicator.

• Experiment with different system set-ups and receiving antenna locations.

• Keep a .4-inch distance between the talent's body and the transmitter antenna and/or monitoring receiver antenna. A piece of aquarium tubing slipped over the antenna may help.

• During a performance if a receiver is on, keep its corresponding transmitter on. All transmitters in a system turned on will often mask minor incompatibilities. Otherwise, the receiver may grab an unwanted signal on or close to its operating frequency. Alternately, if the transmitter is off, make sure that the receiver is muted at the mixing console.

There's a lot more at:
www.sennheiserusa.com/spectrumreallocation