Same song, second verse. Or, as Yogi Berra once declared, “It’s déjà vu all over again.” Alas, soon it will be time to bid “sayonara” to any 600 MHz band wireless systems operating in your church. Not too long ago, we had to scrap all our 700 MHz band wireless systems or, at best, trade them in for a discount on new systems. Many of us assumed at the time that the 600 MHz band was safe territory, so we went there for replacement systems. Oops.Fortunately, at our church, all the nine-year-old Sennheiser G2 systems in our sanctuary are in the still-safe 500 MHz range.
Not long ago, many of us had to scrap all our 700 MHz systems and purchased in the 600 MHz band. Oops.
Opting for the lowest frequency bands available was the sound contractor’s decision before my time, and he later told me that he had suspected the FCC would continue chopping away at frequencies from the top down. Good call!I was similarly pessimistic when purchasing new classroom systems (more on this later), so all we have to replace this time around is one back-up beltpack system. Your church may not be so lucky, but even if you do have to replace several systems— and you may need to do it quickly—you have plentiful options across a range of price points. Which option is best will depend largely on the system’s application and its location on your church campus. We’ll start at the top and work our way down.
Top Tier Systems: Still UHF … Mainly
Top tier systems will be those used in the main worship space of most contemporary churches. Here, the requirement is for a dozen or more simultaneous channels of high-quality wireless microphones, plus additional channels for wireless IEMs. Auditoriums may be large, so extended RF range is important, as is near-bulletproof reliability and freedom from interference. For such demanding requirements, you really have to stick with premium UHF systems, either analog or digital. No other chunk of the frequency spectrum can offer all the advantages, including relatively low background noise, good propagation characteristics for extended range (up to 300 feet), ample spectrum available for high channel counts, and favorable FCC regulations for allowed frequency deviation (more deviation = better frequency response) and transmitter output power.
Although UHF remains first choice for “top tier” systems, it’s going to get crowded in this neighborhood as more TV stations and other wireless users cram into what’s left of the available spectrum. That’s why, when evaluating replacements for departing 600 MHz systems, you should look for as much tuning bandwidth as you can afford. Wider tuning bandwidth gives you greater frequency agility, allowing you to find a space for all the channels you need without running into interference—either from outside or from other systems in your own church. So the next question is, within the universe of UHF systems, should you stick with analog wireless microphone systems or move up to digital?
There’s no easy answer here, as the circumstances in each church will be different. Certainly if your church has a split system, with some units operating in the 600 MHz range and others below it, it might be best simply to stick with what you have for the sake of uniformity, replacing only as needed. But even if you have to start over from scratch, analog UHF remains viable technology for many small- and mid-sized churches. Audio performance is top notch in the better systems, and at a lower price for systems of otherwise comparable quality—though the gap has narrowed of late. Also, analog can be more forgiving when reception is marginal: audio quality may degrade somewhat but a digital system may mute completely. But digital systems certainly have advantages for critical use scenarios, including smart battery technology for longer operating cycles, more efficient packing of available frequencies for higher channel count, signal encryption, and intelligent avoidance of interference.
Finally, a note on the subhead above, which says “UHF … mainly.” That’s because some manufacturers are now offering premium digital systems in the high-band VHF range that previously were made for UHF only. Shure, for example, announced last year that their ULX-D and QLX-D systems would be available in the 174 – 216 MHz range (TV channels 7-13). This was mainly to accommodate intensive users in urban areas with very high RF density where every chunk of available spectrum needs to be utilized. Performance is the same in all respects, although different antenna systems are needed for best results to accommodate the longer wavelengths.
The cost per channel for UHF systems varies widely. If you only need around 10 channels or less, good quality systems are available for as little as $300 per channel. But if you need many more simultaneous channels, you’ll have to pay a premium for the wider tuning bandwidth and more precise channel packing. Figure at least double for systems that can accommodate more than a dozen. For premium digital UHF, per channel costs start near $1000 and go … well, through the roof if you want the same high-end systems used on hit Broadway shows and major network TV shows. Finally, in case you missed all the publicity, major manufacturers (Shure, Sennheiser, Audio-Technica and perhaps others) will ease your pain with generous trade-ins or rebates on 600 MHz wireless gear. Lectrosonics is offering a “re-blocking” service on its systems, swapping out the RF circuit boards at a reduced cost.Now we move down a notch, to the main worship space in smaller churches or to secondary spaces like youth rooms or café-type common spaces. Here, room dimensions are usually more limited so extended range is not as critical. And five to 10 simultaneous channels will do just fine.
Applications like this are tailor-made for the new generation of wireless microphone systems that use the open-to-all ISM bands. ISM stands for “industrial, scientific and medical,” though use has expanded to all sorts of low-power applications—most notably Wi-Fi computer networks. Devices in this frequency band require no licensing, work anywhere in the world, and are generally easy to set up and operate.
Third Tier: VHF Again?
All wireless systems using these bands are inherently digital, and performance specifications are right up there with equivalent UHF systems. But there are some limitations. Range can be much more limited than either VHF or UHF systems. Yes, up to 200 feet line of sight is possible, but it can be reduced considerably by the total amount of other activity in the same spectrum. (Standard remote antennas don’t work with these high frequencies, though Audio-Technica’s System 10 Pro has a clever work-around with remote receivers connected via Cat-5a cable.) With ISM spread-spectrum systems interference is not so much a matter of one specific conflicting frequency as it the total thickness of the “WiFi soup” in and around the building. The same applies to channel count: the thicker the “soup,” the fewer channels available.
Nevertheless, in scenarios where receivers can be placed near the stage, these systems can be highly reliable and offer a lot of bang for the buck if you just need a few channels. And if this room happens to be near your main worship space, the main side benefit is that you are freeing up precious bandwidth for your primary UHF system. There is no interference between the two systems.Most systems of this type fall in a relatively narrow price range of $250 to $800, with more expensive systems allowing more simultaneous channels and added features like automatic frequency management, integrated DSP and remote control via smartphones.I define “third tier” as applications where program is primarily speech only, no more than three simultaneous channels are required, and a slightly higher noise level can be tolerated. Typical church examples might be a classroom, a fellowship hall or a kids’ room where even toddlers get mike time.For these situations, low-cost VHF systems are worth considering, in particular those that occupy the “traveling band” between 169-172 MHz.
No TV stations are allowed here, though the band is open to low-power government and business use. But unless you have a Coast Guard base or power plant in the neighborhood, you’re probably okay. We’ve had systems of this type in our large classroom for five years with no problems. You’ll find a lot of VHF systems out there at extremely low prices, many from companies you’ve probably never heard of. Be skeptical below $100. But Audio-Technica’s good quality System 9—a recent upgrade from our church’s discontinued System 8—offers four selectable channels and costs a mere $169. It does the job, is likely safe from future spectrum auctions, and keeps one more UHF frequency open for “top tier” use.
Final Option: Go Retro
Take the male XLR plug on one end of the mic cable, plug it into the microphone, plug the connector on the other end into an input on the stage box. The FCC and T-Mobile can’t touch this one.
The 600MHz CRUNCH: Situation Update
In an FCC auction earlier this year, large swaths of radio frequency spectrum between 616 and 698 MHz (TV channels 38 – 51) were sold to large telecom companies, with T-Mobile purchasing the lion’s share of bandwidth. The remaining TV stations in this band will vacate their assigned frequencies over the next three years. The good news is that wireless microphone and in-ear monitor (IEM) users may continue using open portions of this spectrum until the new owners light up their cell towers in the vicinity. The bad news is that T-Mobile has an aggressive schedule for utilizing its multi-billion-dollar investment. Cell towers using these frequencies are in active testing as of now, starting in more rural areas where no TV stations are currently using the purchased bandwidth. As soon as the new owners occupy the frequency locally, use by your church’s wireless systems becomes problematic – and illegal.Further complicating matters is the fact that all TV stations currently occupying the purchased spectrum must either cease operation or move to a new channel in the remaining UHF or VHF spectrum. (This is called “repacking.”) The end result is that even less space will be open for use by wireless systems as there will be more active TV channels in the remaining available spectrum. The situation is far from hopeless, however. There’s still plenty of “open air” available for wireless systems, but you need to understand all your options and weigh all the tradeoffs involved before making your post-600 MHz investments.
Bruce Borgerson operates Strategic & Technical Communications and heads the tech team at the First United Methodist Church, both in Ashland, Ore.
