I don’t know why, but things seem to come in waves. Lately, the wave has been wireless microphones. I’ve heard from several people recently who are having trouble with their systems, and most of the problems revolve around two main issues: improper design and installation, and frequency coordination.
Today I’ll tackle the first issue, and next time will hit the second one.
Wireless is harder than you think. Once you move beyond one or two channels of wireless in a building, you need to make sure things are designed to work together and are installed properly. While it’s true you can stack a bunch of receivers with their 1/4- or 1/2-wave antennas at FOH and they will work—some of the time—it’s not the right or best way to go.
And as an aside, the plural of antenna is antennas. Bugs have antennae, wireless mics don’t. Antenna, antennas. Got it? OK. Moving on…
The problem is, once you start putting all those antennas next to each other, they start causing interference with each other. Fire up enough channels and there are sure to have issues.
The answer is proper antenna distribution and combining. A lot of people get confused on these two terms, so let me start by defining them. Antenna distribution is used for wireless mics. Basically, you take a couple of specialized antennas—usually using long periodic dipole arrays (LPDA), AKA paddles—spread them out so they cover the intended area and run them into an antenna distribution system. Most antenna distributors will output the signal to 4-8 wireless receivers. They typically have a cascade out to connect to a second distro in case it’s needed.
An antenna distro will cost anywhere between $1,000 to $3,000-plus, depending on the system. Some might say, “But Mike, that’s so expensive!” Yes. They are. Wireless is hard. And expensive. That’s why we wire everything we can. And there is no sense spending $10,000 on wireless mics but trying to save $2,000 on antenna distribution. The systems simply won’t work well. Do it once, do it right.
When it comes to wireless in-ear monitoring systems (IEMs), we’re dealing with transmission antennas. This means an antenna combiner is needed. The combiner is similar to a distro, only in reverse. It takes the outputs of four to eight IEM transmitters and combines them into a single antenna signal that goes out to the antenna itself.