So you’re thinking about either adding or switching to wireless DMX? Great. For those who don’t know, wireless DMX simply replaces DMX 512 cables in a lighting system. The data from the controller goes into a DMX connector on a wireless transmitter, and the data moves wirelessly through the air. For the user, it works just like a cable, but without the cable.
When I heard about wireless DMX 512, I was excited and nervous. The idea of going wireless was thrilling – we wouldn’t need to purchase DMX cables to run to the lighting fixtures all over the venue anymore. We purchased a few different brands in different price points, all worked 100% out of the box, a few had more options than others, but I was still nervous about them not working or losing signal. So, as we added to our system we slowly integrated into using the wireless system until we reached the point of trusting the wireless system. I don’t put a receiver at each unit unless they are separated from the other lighting fixtures. I usually will put a wireless receiver at each electric batten, truss or pipe, then use DMX cable for the short runs to daisy chain between the units, make sure to use a DMX terminator at the end of the chain. Other designers or operators may use wireless on every unit, that’s up to your design. I can usually run 9-12 units per wireless receiver, which means I only need a few short jumpers to operate that line of fixtures.
What to expect
Good quality wireless DMX is carefully engineered to avoid delays in the process of transmitting and receiving, and not suffer dropouts that might be caused by other wireless technology in the vicinity. The wireless DMX systems do this so well that the reliability of the wireless connections surpasses the reliability of the wired connections for some metrics; the likelihood of channel jumping or ghosting is much lower for wireless than for wired, because the original DMX protocol from 1986 does not provide error detection or correction. All reputable wireless DMX systems use sophisticated methods to avoid and eliminate data errors.
Wireless DMX is ideal for individuals using wired DMX equipment who would like to get rid of cables, or avoid having to install them. In theatre, it is used, along with wireless dimming, to get DMX data to mobile set pieces and small props. It can also be used to move data from the main DMX controller to fixtures up on a pipe, or in a dimmer rack, or anywhere else. In motion picture production, wireless DMX is used to control lighting inside vehicles, on building rooftops, and much more.
Churches can use wireless DMX to easily add new lighting to existing facilities, without needing to break walls to run cables. You can eliminate unsightly cables running along the floor and around doorways by using wireless DMX to control lighting trees, fog machines, and special effects.
In large productions, wireless DMX is used to reduce setup times by eliminating the need to feed cables and then reel them back in. Wireless DMX can also be used in costumes and in specialty items like LED-infused microphones and guitars.
Concerns
Wireless DMX users need to be aware of other wireless systems in use, and if their system is interfering with other systems. They also need to think about DMX security, and take steps to make sure their system can’t be hacked. RC4’s System IDs eliminate that concern.
The venue itself is another concern. The technology needed in a stadium or arena is different that the ideal technology for a black-box theatre. Some wireless DMX systems, regardless of the target market and the application, are plug-and-play and require one or two simple button presses to pair receivers with transmitters. Others work right out of the box with no need to touch anything at all.
Almost all commercial wireless DMX systems operate in the 2.4GHz Band, which is harmonized worldwide. Although the generic range of this band is from 2.400GHz to 2.5GHz, the more constrained truly international range is 2.412 to 2.472GHz.
It is still improving with breakthroughs of multiverse wireless DMX, which is great for larger systems. Let’s talk about 2.4GHz & 900MHz Bands. The 2.4GHz Band is available nearly everywhere around the world, it passes through objects well, it has a great broadcast distance, and the multiverse can carry five universes of data. Its weakness is that it already operates in a crowded band. A general rule of thumb in home networking says that Wi-Fi routers operating on the traditional 2.4 GHz band reach up to 150 feet (46 m) indoors and 300 feet (92 m) outdoors.
The 900MHz Band operates in a less crowded band, passes through objects better than 2.4GHz, it even broadcasts further than 2.4MHz, its Multiverse can only carry up to four universes of data, weakness at this time is its only available in North America, Brazil, Australia & New Zealand. In addition, make sure your wireless signal is not interfering with other systems. Higher frequencies can use less power, but will reflect off of dense surfaces. The 900MHz radio system is at a lower frequency and will penetrate surfaces more easily. Tempest 2.4GHz systems are more reflective and tend to be affected more by bodies, foliage, or moisture that can attenuate the signal.
Here are a few tips for the best performance: try to keep the transmitter and receiver within line of sight. Yes it will probably still work fine, but the fact remains true. Try placing or flying the antennas as high as possible to avoid broadcasting through people – use the specialized antennas. Things to avoid are simple: stay out of a radio congested area and broadcasting through scenery and walls. Also consider that most transmitters and receivers will require power, they don’t draw a lot but plan ahead and make sure you have a power connector nearby.
So, if you’re about to switch over for the first time or just have recently, I would like to hear your opinion. Its time to go wireless!
Bill Di Paolo has worked in live production for over 30 years, He is the owner and technical director of Entertainment Services, a production company based in upstate New York that handles lighting, audio and video for events of all sizes in the Northeast. If you have any questions, feel free to contact him at bdipaolo@worshipfacility.com.
