Wireless DMX

BillConnerFASTC said:

Wish you could tell me why this approach was so unreliable in Iowa public school to the point we removed wireless and replaced with wired. This year.

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Bill, ETC has a great technical service team. Did you call them to discuss the setup and troubleshoot? I'm with City Theatrical and we provide the wireless technology and I would be happy to discuss the project so we can determine the circumstances that caused issues. I expect that the school is functioning ideally with the wired solution, but any discussion about system integration can help with general industry knowledge.

BillConnerFASTC said:

Wish you could tell me why this approach was so unreliable in Iowa public school to the point we removed wireless and replaced with wired. This year.

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What gear list? How many receivers? Antenna distances and geometry? In the path of any broadcast studio to transmitter microwave links? Was a spectrum analysis done? What other wireless gear did the school run- master clocks, security radios or video, WLAN for students, ??

We could all learn from this.

I had a client once which lost T1 connectivity reliably every afternoon. A ton of detective work finally found an industrial shop on the same power feed running a device that generated crazy EMI/RFI when it was on. Calling a witch doctor was next on my list, tho!

I volunteer in a high school auditorium. We just recently (within the past year) replaced about 22kW of overhead incandescent border lights with 19 LED fixtures. Our dealer recommended ETC ColorSource Relays to wirelessly deliver DMX to our 3 electrics. I was skeptical considering it was 2.4GHz and we have over a dozen wifi APs visible from our stage (with literally hundreds of wifi clients connected during the school day). The dealer pointed out the installation costs associated with running 3 cables from stage level up to the grid and back down, so we ended up giving the wireless a chance (the budget was pretty tight on this project). I was pleasantly surprised: out of the box, it appeared to work perfectly, and I've only noticed a few glitches here and there. It's not perfect, but considering the only issues are rare and last no more than a blink of the eye, we're okay with it. The glitches do seem to get more frequent during the school day, but are few enough I haven't been able to actually observe it happening other than seeing a light flicker out of the corner of my eye. I suspect it is caused by interference from the school's wifi, but I have no hard data to back that up. I know the ColorSource transmitter has some options to help tweak the wireless link for better performance, but have not had the chance to experiment yet.

If you choose to go wireless, be careful how far apart the transmitter and receiver will be, consider how much other stuff you have in the same frequency band, and keep in mind demoing a system for an hour or two probably will not reveal anything but the biggest issues. Otherwise, I think the wireless technology is reasonably close in reliability to a wired link in most circumstances. If you have the budget to pay labor costs to install a cable, go that route; if not, give wireless a try.

Personally, I would not consider using wireless for a permanent theater install, but the OP asked for wireless suggestions.

No offense intended to the RC4 stuff, but it simply does not have the appearance of a professional product. It looks like a kit I would have bought at Radio Shack 20 years ago. Also having a wall wart power supply is a non-starter for me. Maybe there are some models with a better build quality, but I could not find them on their website; I actually could not identify what boxes I needed to simply send and receive one universe of DMX. I know they exist because I used to have a pair.

I think the price point of the RC4 products is good, and I could see them being very useful in set pieces and practicals, but being small and light, also makes them easily grow legs. For a robust system from a booth to electrics, I would be looking at Wireless Solutions. They offer units that have a mount for pipes, built-in power supplies, and powercon connections. Thier rack mount units would be a good fit for on stage or in booth transmitters. Also, W-DMX seems to have become the most widely adopted for fixtures with built-in receivers.

In general the Idea that "Wireless is a mature tech, and is now just as good as cables" is hogwash. The spectrum has been getting increasingly crowded, and with the FCC selling off huge chunks of spectrum that were traditionally used by our industry, it is getting more difficult to use any wireless technology reliably. I have seen people posting about only having a few glitches a day, and to me, any glitches are too many, especially where it is practical to go hard wired.

Ben Stiegler said:

What gear list? How many receivers? Antenna distances and geometry? In the path of any broadcast studio to transmitter microwave links? Was a spectrum analysis done? What other wireless gear did the school run- master clocks, security radios or video, WLAN for students, ??

We could all learn from this.

I had a client once which lost T1 connectivity reliably every afternoon. A ton of detective work finally found an industrial shop on the same power feed running a device that generated crazy EMI/RFI when it was on. Calling a witch doctor was next on my list, tho!

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I have not gotten a detailed response from ETC. I presume the dealer did seek help.

Under 500 seats and small stage, no fly, one big room. Less than 100' from upstage to rear wall., with transmitters on centerline about 10' from rear wall and one maybe 15' from upstage wall. I think 6 or 7 recrivers on battens - over stage and over house - maybe 15' off center. Basically everything just under joists around 22'.

Everyone has their opinion, usually based on personal experience. No doubt there have been a few misbehaving wireless dmx systems in the world. It's a real shame.

If I provided the tech and it's suffering "a few glitches per day," I want to know about it and I will fix it. If you didn't tell me about it, I didn't know there was a problem. This is a very important point, it applies to all brands and suppliers: we can't fix a problem we weren't aware of.

The complaint about RC4 build quality arises from time to time, and i understand it. We make everything as light and small as possible, to be used in costumes and small set pieces, as well as anything else. We all like the weight of a heavier object in our hands, but we don't like it in a dress. (On the other hand, nobody is complaining about our RC4Magic Lifetime Warranty, and our service bench is not very busy. Last week we repaired a dimmer that was sold in 2010. No charge to the customer, and it's back in service in a large system. They aren't suffering a few glitches per day, not in 2010 and not now.)

We understand all the bandwidth issues -- it's our business. All we make is wireless dmx and wireless dimming and we offer the only systems you can buy today that operate in the 900MHz band. If what we do didn't work we wouldn't be here. We've been here for 28 years and I sold my first 900MHz system in 1994!

It's mature technology. I'm speaking from experience, too.

Jim
RC4

Jim, I'm with you here, for sure. The unreported cannot be fixed.

I'm not here to throw shade on any particular products or manufacturers of wireless products (and certainly not yours!). In reading the responses to this thread I'm left wondering exactly why *wired* DMX seems to be such a challenge. That's probably best left for another thread.

In many facilities, it requires electricians, contracts, permits, and inspections. Where battens fly, there are issues of cable management, and the need for it to be damn fool proof.

I rarely use wireless for permanent install but sometimes some use is warranted.