After 10,000 wireless projects we’ve seen and heard it all. Here are the key concepts and techniques to make your wireless microphone system dropout and interference free.
Why do wireless mics drop out anyway?
"The Diversity Fin Antenna is simply the best all-around solution for multiple wireless mic setups." -Ball Electronics.
Loss of wireless mic range is typically caused by competition from localized interference. This interference can be caused by TV stations, motors, LED lighting, anything with a computer chip, and even cell phone service in the 600 MHz band. When all of these sources are added together, they form your noise floor. To help mitigate this problem, directional antennas, and bandpass filters can be used with high-quality coax cables.
Multipath interference is caused by something reflecting your transmitter's signal. The most common things to reflect your signal are metal objects in the venue and other boundaries. These reflections flip the polarity of the signal and arrive out of phase, causing cancellations in your receiver's antennas.
Cross-polarization fades, also known as signal cancellation, can happen when the direct signal of your wireless mic and reflected multipath signals mix in your antennas. Proper antenna position can help mitigate this issue. However, since antennas have to be separated by a certain distance to keep them from interfering with each other, the signal in each antenna will not be in the same wave period or phase. For maximum efficiency, the receiving antennas for your wireless microphone systems need to match the polarization of the microphone transmitters.
"FOH Productions proudly uses a multitude of RF Venue products. They are reliable every single time, easy to use and operate, and eliminate any wireless dropout issues one might possibly have while on show site.
The audio crew is always excited when they pop open one of our kits and see that it contains RF Venue products." -FOH Production
How to Set Up Your Wireless Mic System for Success
As more wireless devices compete for less available RF spectrum, understanding the operating conditions of your wireless mic system has never been more critical. We used to be able to use the auto scan button on the wireless microphone receiver which was suitable to scan and sync up the frequency of your microphones. However, there are too many things that can interfere with the signal, so establishing what the baseline conditions look like in your venue is a critical first step.
An RF link budget is a basic calculation that anyone can do to give them a sense of how well their wireless mic system will perform. Creating a link budget will start with the power output from the wireless mic system.
More is better, right? Well, yes and no. More power increases intermod problems when using more than one transmitter, and it is a big problem when you use a dozen or more transmitters. The more RF that is flying around the room, the more likely something will eventually end up in your system as noise.
Make sure you take the time to set your antennas up correctly; it is crucial to improving your system. Omni antennas, such as the whips that are provided with a new wireless microphone, pick up in a 360° horizontal circle, so they cannot be aimed. They offer low gain and no rejection of local interference. Directional antennas, with paddles and helicals, provide additional range and, when aimed correctly, can reject 50 percent or more of local interference.
Have you ever heard of antenna distribution for wireless audio? Or have you heard about it but do not really know what it is?
Through countless conversations with our customers, RF Venue has discovered that many interference and dropout issues boil down to users with multiple wireless mics and either no antenna distribution or improperly deployed distribution. Adding proper antenna distribution can eliminate a lot of dropouts and interference.
"We upgraded a 16 channel wireless mic system located next to a College radio station. The system had a lot of problems before we put in the RF Venue DISTRO4 system and now it’s like a whole new system with no problems." - Audio Visual One
One of the primary places systems fail or degrade over time is in the coaxial cables that connect the antennas to the distribution and the cables that connect the distribution system to the wireless microphone receivers. Always use high-quality, low-loss, double-shielded 50-ohm coaxial cable for your wireless system. Unless your system is permanently installed, you will want to check and change your cables over time, especially if they are frequently handled.
RF Spectrum conditions are dynamic and operating a wireless mic system during a live event vs. an hour before the event can be two wildly different things. The best way to avoid dropouts and interference is by monitoring and upgrading your system over time. Simple plug-and-play tools such as RF bandpass filters help eliminate interference from your microphone system. By fine tuning the system with more specialized antennas, placement, and other simple techniques, your wireless mics can work in unpredictable environments.
Check out this 90-second live RF demonstration from a busy convention floor!
why wireless mics drop out webinar
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We recommend RF Venue to our customers because their products are built with quality and they deliver clean RF frequencies to the microphones and IEM's we install and provide. I am confident in using wireless products since we have started using RF Venue products. Dropouts are near zero for our large corporate events using 30 or more wireless units.
Gary McAnelly, Creative AVL Solutions
We recommend RF Venue products because they are not only well engineered, but thoughtfully engineered to solve RF problems across all manufacturers and product platforms. That's a rare and valuable approach to a product line.
Edward Vigueira CTS, PSX Technologies