A wireless system for your guitar, mic, or in-ear monitor can really open up your onstage experience. No longer tied to your amp by cables that can tangle and snag, you find yourself free to move anywhere on the stage and you can focus on putting on your very best performance. But as Spinal Tap's infamous Nigel Tufnel discovered, few things are more frustrating than a wireless system that isn't working as intended. When you set up your wireless just the same as the last time and it isn't working, you might start to feel like invisible little gremlins are out there messing with you. Fortunately, there is no such thing as gremlins and just like everything else on Earth, your wireless operates in accordance with the laws of physics. There is a reason the system isn't working, and the better you understand it the better your chances of avoiding performance issues with your wireless systems. In this series we will be learning the basics of setting up a wireless system and discuss ways to stop problems before they happen.
Stacking the Deck in Your Favor
One of the reasons wireless problems crop up unexpectedly is interference typically beyond your control. There may be other radio signals in the area competing for bandwidth and EMI (Electromagnetic Interference) from electrical appliances and wiring which can generate interference signals of their own. Radio bandwidth is only getting more crowded and the more you are in the big city areas the more you may have issues. Every venue and area has its own physical layout issues to consider as well. In order to stack the deck in your favor, a methodical approach to your setup will help you compensate for the particular factors in each venue.
Physical Layout is Crucial
If the invading alien spaceships in Independence Day weren't able to transmit around corners, your wireless probably can't either. Radio signals work on a principle called 'line of sight.' Your radio signal can 'see' through some things you can't (like a curtain) but solid objects (even a performer's own body in extreme situations) can block the signal. Begin your setup by planning carefully so you have line of sight from transmitter (TX) to receiver (RCV), and they are as close as possible to one another. Avoid metal objects, walls, electrical panels, large groups of people, etc. when locating your antennas. Anything between the TX and the RCV will absorb RF energy and can cause dropouts, so be meticulous when setting up. If you have the option, keep the antennas as high in the air as possible. Singers who cup their hands around the transmitter on a wireless mic can severely affect signal strength, as can coiling the extra antenna cable on your instrument wireless. Every one of these impediments can reduce your signal strength and contribute to dropouts and interference.
Antenna Etiquette: "I'm sorry I just need a little space..."
When locating multiple TX/RCV antennas try to keep one wavelength of space between them (just under 24" for a 500MHz system) to avoid interference. If you don't have another option, 1/4 wavelength (about 6") will usually work, but you'll have a higher risk of interference the closer the antennas are to one another. Consider putting each instrument wireless in the performer's rack, close to where they stand and separate from the other wireless systems. Arrange the TX antennas on your wireless Personal Ear Monitors in a similar fashion to keep one channel from affecting the other. Also note that in an In-ear wireless monitor system the base unit is a transmitter and in a wireless microphone or instrument belt pack system the base unit is a receiver. Don’t place these units right next to each other. This would basically be jamming yourself. The in-ear TX can overpower your mic’s RCV and block out the microphone. With a diversity system arrange the antennas at a 90 degree angle to one another. This helps prevent dropouts when your performer is moving around onstage. In a more complex system with multiple frequencies operating at the same time, you may need to invest in an antenna distribution system which helps reduce interference between multiple channels.
Physical Setup is Only Part of the Game
Getting the optimum physical configuration for your wireless will go a long way towards achieving reliable performance. Stay tuned for Part Two of this series where we'll learn how to adjust your system settings to make the most of your available bandwidth.
Where do you place your wireless systems? Let us know in the comments.