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Wireless Microphone Channel Calculator

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Quick answer

How many wireless channels you can run is decided by how many 6 MHz TV channels are empty at your address, not by your seat count. A digital system fits about 8 compatible channels per empty TV channel and an analog one about 4, so four open TV channels carries roughly 32 digital channels or 16 analog.

Almost every church asks this question the wrong way round. The number of wireless microphones you can run has nothing to do with how many people you seat and everything to do with how much empty television spectrum exists at your street address. A church in rural Montana can run twenty channels where a church in Chicago struggles with eight.

Two things set the answer: how many 6 MHz TV channels are locally unused, and whether your systems are analog or digital. Enter both below. The grid underneath filters to systems that suit the density you need.

Wireless microphone channel calculator

Count only positions that genuinely cannot be wired.

From a receiver scan in the room. Four is typical of a suburban location.

In-ear transmitters compete for the same TV channels.

Capacity in your spectrum

32 channels

Wireless systems that suit your channel count

Top matches update when you change your numbers.

Shure BLX24R/B58 Rack-Mount Wireless Audio System J11 Band (596–620 MHz) – BLX4R Receiver, BLX2 Transmitter with Beta 58A Mic, Up to 14 Hr Battery, 300 ft Range
Shure

Shure BLX24R/B58 Rack-Mount Wireless Audio System J11 Band (596–620 MHz) – BLX4R Receiver, BLX2 Transmitter with Beta 58A Mic, Up to 14 Hr Battery, 300 ft Range

$539.00 Specs and sizing

A rack-mounting BLX receiver with the Beta 58A capsule, whose tighter supercardioid pattern buys real gain before feedback on a loud platform.

Check before buying: This J11 unit tunes 596 to 620 MHz, and only the part below 608 MHz is legal to operate in the United States: 608 to 614 MHz is TV channel 37 and 617 MHz upward was sold off in the repack. The system is legal to own and use, but set every frequency below 608 MHz and ignore the top of its range.

Best for: A permanent rack install where the lead vocal fights the wedges

Check price on Amazon
On this page
  1. Why does the TV band decide how many microphones I can use?
  2. How many wireless channels fit per open TV channel?
  3. Which frequencies are legal for church wireless microphones?
  4. How do I find out how many TV channels are open at my building?
  5. What if UHF is crowded where we are?
  6. How many channels does a church actually need?

Why does the TV band decide how many microphones I can use?

Wireless microphones in the United States operate as secondary users in the UHF television band, 470 to 608 MHz. That means they may use spectrum a television station is not using in your area, and they must not interfere with one that is. Each television channel is 6 MHz wide, and a handful of microphone frequencies fit inside one of those unused channels.

The limit inside a TV channel is not bandwidth, it is intermodulation. When two transmitters operate close together, their signals mix in the receiver front end and produce spurious products at predictable frequencies, notably 2f1 minus f2 and 2f2 minus f1. Put a third microphone on one of those products and it will not work, no matter how clean the band looks on a scanner. Coordination software exists to find sets of frequencies where no product lands on another channel.

Analog systems need wide guard bands to stay clear of those products, which is why they fit only about four channels per TV channel. Digital systems transmit in a way that produces far fewer usable products and need much tighter spacing, which is the single best reason to pay for digital once you pass about six channels.

How many wireless channels fit per open TV channel?

Realistic compatible channel counts. These are working figures rather than theoretical maxima, and a coordination tool will sometimes beat them and sometimes not reach them depending on what else is transmitting nearby.

A digital UHF system fits about 8 compatible channels per empty 6 MHz TV channel, so four open TV channels carries roughly 32 microphones where an analog system would carry 16.

Compatible wireless channels by system type and available TV spectrum
System typePer TV channelMinimum spacing2 TV channels4 TV channels6 TV channels
Analog UHF4 per TV channel400 kHz81624
Digital UHF8 per TV channel250 kHz163248
High-density digital mode15 per TV channel125 kHz306090

High density mode trades range and audio bandwidth for channel count and is intended for large productions rather than a Sunday service. Do not plan a church system at its limit.

The United States position after the 600 MHz repack. This matters more than the channel count: operating in a prohibited band is illegal, and a great deal of secondhand gear tuned to those bands is still being resold.

In the United States, 470 to 608 MHz is the working band for church wireless microphones, and 617 to 652 MHz, 663 to 698 MHz, 698 to 806 MHz and TV channel 37 are all prohibited.

US wireless microphone bands and their legal status
BandStatusLicenceWhat it means for a church
VHF 169 to 216 MHzLegalUnlicensed, Part 15Legal but crowded and antenna-hungry. Cheap systems live here; ranges suffer indoors.
UHF 470 to 608 MHz (TV 14 to 36)LegalPart 74 licence or unlicensed under Part 15The main working band. You must operate in locally unused TV channels, which is what coordination means.
608 to 614 MHz (TV channel 37)PROHIBITEDProhibitedReserved for radio astronomy and wireless medical telemetry. Never legal for microphones.
614 to 616 MHz guard bandLegalPart 15, 20 mW limitA narrow sliver of the guard band, not the duplex gap. Usable but tiny: perhaps two or three channels at low power. A further narrow allocation exists in the 652 to 663 MHz duplex gap that this site does not model, so check the current FCC rules before planning around it.
617 to 652 and 663 to 698 MHzPROHIBITEDProhibited since the repackSold to mobile carriers. Operating a microphone here is illegal, and secondhand gear tuned to it is worthless.
698 to 806 MHzPROHIBITEDProhibited since 2010Public safety and mobile broadband. Gear from before 2010 often sits here.
902 to 928 MHz ISMLegalUnlicensed, Part 15Shares space with cordless phones and telemetry. Fine for a handful of channels.
1920 to 1930 MHz DECTLegalUnlicensedSelf-coordinating digital systems. Very easy to deploy, limited range and channel count.
2.4 GHz ISMLegalUnlicensed, Part 15Shares the band with every Wi-Fi access point in the building. Workable if you control the Wi-Fi plan.
5.8 GHz ISMLegalUnlicensed, Part 15Cleaner than 2.4 GHz in most buildings, shorter range, needs line of sight.

Rules change. Confirm the current FCC position before buying, and be especially careful with used equipment, which frequently sits in the bands sold off during the repack.

How do I find out how many TV channels are open at my building?

  1. Look it up before you scan. The FCC publishes which television stations broadcast in each area. That gives you the list of channels you must avoid, which is the starting point rather than the answer.
  2. Scan in the actual room, with everything on. Most receivers have a scan function. Run it in the room where the microphones will be used, with the building lighting, LED walls, dimmers and Wi-Fi running, because all of those raise the noise floor and some of them radiate directly in band.
  3. Scan at the time of day the service happens. Spectrum is not constant. A Tuesday afternoon scan can miss a nearby production, a school event or a weekend broadcast that will be there on Sunday.
  4. Use the manufacturer coordination tool for more than six channels. Every major manufacturer publishes free software that finds intermodulation-free frequency sets. Below about six channels the receiver scan is usually enough; above it, guessing will cost you a service.
  5. Write the frequency plan down and tape it inside the rack. A plan that lives in one volunteer’s memory is a plan that fails the week they are away. Record the frequency, the band and the transmitter for every channel.
  6. Rescan after any change nearby. A new broadcast tower, a neighbouring venue installing systems, or a repack of the band itself all change the picture. Rescan at least annually.

What if UHF is crowded where we are?

If the scan comes back with very little open spectrum, the honest options are to move out of the TV band entirely rather than to fight for it. The 900 MHz ISM band, 1.9 GHz DECT, 2.4 GHz and 5.8 GHz are all unlicensed and none of them care what the local television stations are doing.

The trade is real and worth stating. A 2.4 GHz system such as the Audio-Technica ATW-1102 Wireless Handheld Microphone System or the Shure GLXD24+/SM58 Digital Wireless Vocal System - Z3 Band shares its band with every Wi-Fi access point in the building, so it works well where you control the wireless network and badly where you do not. DECT and 5.8 GHz are cleaner in most buildings but have shorter range and lower channel counts. None of these will carry twelve channels.

For a church that genuinely needs many channels in a crowded market, the answer is digital UHF with a proper coordination pass: the Shure SLXD24D/SM58 Dual Wireless Vocal System - H55 Band puts two coordinated channels in one rack unit, and the Sennheiser Pro Audio EW-D 835-S Wireless Handheld Microphone System, R1-R6 offers a 56 MHz tuning range to work around whatever is occupied.

How many channels does a church actually need?

Fewer than most churches buy. Count the positions that genuinely cannot be wired: the preacher, the worship leader, a roaming handheld for testimony or announcements, and a spare. That is four for most churches, and a church running more than eight should be able to name each one.

Every additional wireless channel is a battery to charge, a frequency to coordinate, a capsule that can fail and a receiver in the rack. A wired Shure SM58 Pro XLR Dynamic Vocal Microphone at $109.00 does not do any of those things. The convention that keeps a service running is one spare transmitter per four channels in service, and a spare capsule such as the Shure Centraverse CVL Lavalier Condenser Microphone in the drawer, because a dead capsule is the most common wireless failure by a wide margin.

Plan the battery side too, with the wireless battery calculator: switching to rechargeable packs is the change that pays back fastest and removes the most Sunday morning stress.

Sources

Frequently asked questions

How many wireless microphones can a church run at once?

It depends on how many 6 MHz TV channels are empty at your address, not on the size of your church. A digital system fits roughly eight compatible channels per empty TV channel and an analog one about four, so four open TV channels supports about 32 digital or 16 analog. Four to six channels is achievable almost anywhere in the United States; twelve needs a scan and a real coordination pass.

What wireless microphone frequencies are legal in the US?

The main working band is UHF 470 to 608 MHz, used in television channels that are locally unoccupied. Also legal are 614 to 616 MHz at 20 mW, 902 to 928 MHz, 1920 to 1930 MHz DECT, 2.4 GHz and 5.8 GHz. Prohibited are TV channel 37 at 608 to 614 MHz, the 617 to 652 and 663 to 698 MHz service bands sold in the repack, and the 700 MHz band since 2010.

Why do my wireless microphones interfere with each other?

Almost always intermodulation rather than the frequencies being too close in a simple sense. When two transmitters operate near each other their signals mix and produce spurious products at predictable frequencies, particularly twice the first frequency minus the second. A third microphone sitting on one of those products will drop out even though its own frequency looks clear on a scan. Coordination software finds sets where no product lands on a used channel.

Is digital wireless worth the extra money for a church?

Below about six channels, usually not: a good analog system sounds fine and costs less. Above six channels it becomes the deciding factor, because digital fits roughly twice as many compatible channels into the same shrinking spectrum. Digital systems also tend to have no gain control to set wrongly, which matters more than it sounds on a volunteer team.

Do we need an FCC licence for church wireless microphones?

Most churches operate unlicensed under Part 15 and accept that they must not cause interference and must tolerate receiving it. A Part 74 licence gives interference protection and access to higher power, but eligibility is limited and most churches do not qualify. Do not let anyone sell you equipment on the basis that a licence is required when it is not.

Can we use 2.4 GHz wireless microphones instead?

Yes, and it removes the TV band question entirely, which is genuinely attractive in a crowded market. The trade is that 2.4 GHz shares its band with every Wi-Fi access point in the building, so it works well where you control the wireless network and poorly where you do not. Range is shorter and channel counts are lower, so it suits a small room with a few channels rather than a large system.

Researched, not professional advice. This page is compiled from published manufacturer specifications, operator manuals, FCC rules, published standards and owner-review consensus, not hands-on testing. Sound system design, rigging loudspeakers overhead, and any electrical work are jobs for a qualified professional: have flown loudspeakers and their attachment points signed off by a structural engineer or a certified rigger, and have all wiring done by a licensed electrician to your local code. Wireless microphone rules change, so confirm the current FCC position before buying. As an Amazon Associate we earn from qualifying purchases.