When did wireless microphones have to stop using 600 MHz?

No later than July 13, 2020, and earlier in specific markets once the new 600 MHz licensee began operating in that area. The deadline has passed nationwide, so operation anywhere in 617–698 MHz is now prohibited regardless of market.

Can I still use my 600 MHz wireless microphones somewhere?

No. The prohibition applies across the United States and there is no waiver process for production use. Gear that only tunes 617–698 MHz has no legal operating range left in the US, though the same hardware may still be usable in other countries with different band plans.

What is the 600 MHz duplex gap and can wireless mics use it?

The duplex gap is the 652–663 MHz spacing between the 600 MHz downlink and uplink. Wireless microphones may use part of it: 653–657 MHz is licensed-only and 657–663 MHz is unlicensed-only, both at 20 mW EIRP. The first megahertz of the gap, 652–653 MHz, is not available to microphones.

Is it illegal to sell 600 MHz wireless microphones?

Yes. 47 CFR §74.851(j) prohibits manufacturing, importing, selling or offering for sale low power auxiliary station equipment tuned to the 600 MHz service band or the guard bands, with an exception for the 653–657 MHz segment. Documented FCC enforcement in this area has focused on manufacturers and marketers rather than end users.

Rules & licensing

The 600 MHz repack, explained

RF ScoutUpdated July 26, 20264 min read

The 2016–17 FCC Broadcast Incentive Auction repurposed 617–698 MHz — former TV channels 38 through 51 — from television to mobile broadband, and wireless microphone operation in that band had to cease no later than July 13, 2020. What survives near 600 MHz is three narrow slivers at 20 mW EIRP: 614–616 MHz unlicensed, 653–657 MHz licensed only, and 657–663 MHz unlicensed. Everything from 617 to 698 MHz now belongs to carriers including T-Mobile, DISH and US Cellular, and gear tuned there is illegal to operate and, with one narrow exception, illegal to sell.

Between 2016 and 2017 the FCC ran an auction that moved a third of the UHF television band out of broadcasting and into mobile broadband. Wireless microphones were not the target. They were collateral. If you own a transmitter that tunes above 616 MHz, this is the reason it is now a very expensive paperweight.

What the auction actually did

The Broadcast Incentive Auction was two auctions bolted together. On one side the Commission paid television broadcasters to surrender their channel assignments. On the other it sold the freed spectrum to mobile carriers. The band that changed hands was 617–698 MHz — former TV channels 38 through 51. Stations that stayed on the air were then reassigned, or repacked, into what was left below 608 MHz.

For a broadcaster that was a channel move with a cheque attached. For a wireless microphone operator it was an eviction with no replacement housing. Mics have always lived in the TV band on a secondary basis, in the gaps between stations. Shrinking the band shrank those gaps twice over: less total spectrum, and the surviving stations packed more tightly into what remained.

The band plan you are living with now

614–698 MHz after the repack
Segment	Range	Who has it
Guard band	614–616 MHz	Wireless mics, unlicensed, 20 mW EIRP
600 MHz downlink	617–652 MHz	Mobile carriers — towers transmit here
Duplex gap	652–663 MHz	Partly available to mics, see below
600 MHz uplink	663–698 MHz	Mobile carriers — handsets transmit here

Licences across the service band are held by carriers including T-Mobile, DISH and US Cellular. The downlink is towers talking to phones; the uplink is phones talking back. Both are orders of magnitude louder than anything in your bag, both are permanent, and neither is going to move for a boom op.

The deadline

You cannot buy your way around it

47 CFR §74.851(j) bans the manufacture, import, sale and offer for sale of low power auxiliary station gear tuned to the 600 MHz service band or the guard bands. The single carve-out is the 653–657 MHz segment. That is why current-production transmitters mostly stop dead at 608 MHz, with a handful of models reaching up into the duplex-gap slivers and nothing at all above them.

What is actually left near 600 MHz

Range	Status	Power
614–616 MHz	Unlicensed only	20 mW EIRP
653–657 MHz	Licensed only (Part 74)	20 mW EIRP
657–663 MHz	Unlicensed only	20 mW EIRP

Three slivers, none wider than 6 MHz, all capped at 20 mW EIRP. At that power you are looking at short, well-behaved links — a lav on a locked-off interview, a hop across a stage — not a transmitter buried under wardrobe two hundred feet away. And the 653–657 versus 657–663 split catches people constantly: adjacent ranges, identical on a scan, opposite licence requirements. The full picture is in what frequencies wireless mics can use.

What it cost, in practice

Roughly 40 percent of the UHF band, gone. 470–698 MHz became 470–608 MHz — 228 MHz down to 138. Every channel count you remember from a 2014 job is now optimistic.
Gear obsolescence. Lectrosonics blocks 24 through 29, Shure's L54 and K53, and the upper Sennheiser ranges all tune into what is now carrier property. They still power on. They are still illegal to transmit on. See the Lectrosonics and Shure block guides for where the safe edges fall.
Tighter station packing. Repacked broadcasters moved down into 470–608 MHz and sit closer together than they used to, so the vacant channels that remain are narrower and less predictable market to market.
Block choice matters more. With less spectrum to hide in, buying the wrong block for the cities you actually work is a real problem. See choosing blocks when you travel.

None of this is reversible and none of it is coming back. The useful response is not nostalgia but better coordination inside the band that remains — knowing which channels are occupied at a given address before you unpack, rather than discovering it during a take. That is the problem RF Scout exists to solve.

Enter a shoot address and get a channel-by-channel advisory across 470–608 MHz, in the blocks your gear actually tunes.

Check what is clear at your location

Common questions

When did wireless microphones have to stop using 600 MHz?: No later than July 13, 2020, and earlier in specific markets once the new 600 MHz licensee began operating in that area. The deadline has passed nationwide, so operation anywhere in 617–698 MHz is now prohibited regardless of market.
Can I still use my 600 MHz wireless microphones somewhere?: No. The prohibition applies across the United States and there is no waiver process for production use. Gear that only tunes 617–698 MHz has no legal operating range left in the US, though the same hardware may still be usable in other countries with different band plans.
What is the 600 MHz duplex gap and can wireless mics use it?: The duplex gap is the 652–663 MHz spacing between the 600 MHz downlink and uplink. Wireless microphones may use part of it: 653–657 MHz is licensed-only and 657–663 MHz is unlicensed-only, both at 20 mW EIRP. The first megahertz of the gap, 652–653 MHz, is not available to microphones.
Is it illegal to sell 600 MHz wireless microphones?: Yes. 47 CFR §74.851(j) prohibits manufacturing, importing, selling or offering for sale low power auxiliary station equipment tuned to the 600 MHz service band or the guard bands, with an exception for the 653–657 MHz segment. Documented FCC enforcement in this area has focused on manufacturers and marketers rather than end users.

Sources

Related notes

Field Notes are general reference, not legal advice or a substitute for the rule text. Spectrum rules change; verify anything you are relying on against the current source before you transmit. See the methodology and disclaimer.