SpectrumTalk

Wireless Mics are a Legitimate Use of Spectrum:
They Deserve More from FCC than
Benign Neglect that Allows Most Users
Only Criminal Spectrum Squatting

My former FCC boss, Dale Hatfield, used to say "if you are looking for interesting new ideas in spectrum policy, look what people are doing illegally and legalize it."

Well most wireless microphone use at present is illegal, a point that many people like to ignore - like the elephant in the room. Why are they illegal? Most wireless microphones in the US are physically Part 74 (broadcast auxiliary) devices operating in UHF TV spectrum in "white space channels" and require licenses. Only those industries specifically enumerated in Part 74 are eligible for such licenses and these are basically only NAB members and Hollywood moguls - all of whom have effective lobbyists in Washington. It is a cozy arrangement born in a different era of both technology and spectrum policy but it is a bad anachronism.

How did we get there?

In ancient history there was only analog television in UHF spectrum. The "UHF taboos" that resulted from both NTSC technology and 1953 estimates of how well future production TV sets could reject signals on nearby channels became self fulfilling prophecies and resulted in only 1 out of 6 channels being used in a given city. There was always tons of white space under this regulatory scheme. The "club" of broadcasters in a given city knew each other well and could work out deals to use this white space in support of their operations without interference. They sought and received FCC blessing for this exclusive use, although at some point Hollywood weighed in and became eligible also. Live theater productions, live concerts, churches, and conference centers are not eligible under Part 74 so their only legal options are low powered unlicensed systems that are secondary (and hence have greater risks of receiving interference) or Part 90 systems with complicated licensing requirements that probably have license transaction costs that exceed hardware costs in many cases.

Some unethical manufacturers and their dealers took advantage of this scenario and started marketing Part 74 wireless mics to noneligibles and "fuzzified" the legal issues. One even has on its website a "Wireless Frequency Finder" to help its customers find frequencies to use illegally. Apparently the FCC has turned a blind eye to this situation for years.

Lord Nelson raising his telescope to his blind eye in the Battle of Copenhagen

That was then, this is now

All of this was tolerable when spectrum was not in great demand, the dominant spectrum policy model was "command and control", there were few technical options for other use of the this spectrum, and there was plenty of white space. But that is all obsolete or becoming obsolete. Even as I write this the 700 MHz auction is winding down and next year TV channels 52-69 will be in the hands of new licensees who will expect to use them after a multibillion dollar auction. The NPRM in Docket 04-186 proposed 3 different options to use white space for broadband distribution in both urban and rural areas. While the broadcasters question the listen-before-talk option and have dragged everyone into obscure testing issues as a delaying tactic, the other 2 options are still on the table without significant objections.

The same wireless mic manufacturers who created the present lawless situation want the FCC to kill off the 04-186 proposals and allowed endless illegal squatting of their customers. The basic problem is that this would result in negligible overall use of a valuable resource: In the best circumstances the spectrum would be used heavily in the Broadway theater district, near megachurches on Sundays, and on the Las Vegas Strip. In terms of space and time, overall spectrum use would be negligible and it would be denied to all other classes of users.

The new technology proposed in 04-186 would result in much greater spectrum user and benefit to both the economy and society, but this should not mean that wireless mic users should be "thrown to the dogs". The users of wireless mics perform valuable are entitled to spectrum access, but access consistent with the current concepts of spectrum policy. They seem to demand continued exclusive access to "free spectrum" - even for clearly commercial operations. Guys, that is not the current era of spectrum policy.

Options for the future

But FCC should find a way to legitimize spectrum access for these users. Keeping them in the UHF-TV band will deny this spectrum to more valuable users but just as FCC relocated hospital-based medical telemetry out of this band into other bands where sharing was feasible, it should enter into a dialog with the wireless mic community (amnesty?) to find new spectrum home(s) where wireless mic use can share with other users on an interference free basis. Maybe there is a need for a coordinator who will charge fees like in the UK. (JFMG is the Ofcom-designated coordinator what what is called "PMSE" in UK-speak.) Unlicensed use and Part 90 use remains an option for users with modest requirements. Audio-Technica, a major supplier, has invested in and developed high reliability ultrawideband-based systems that can

Audio-Technica UWB-based wireless microphone system using MSSI's technology

satisfy the needs of users with needs for less than 14 units in a theater and can live with 12 kHz upper audio range - adequate for many users, but not opera. (This appears not to be a basic technical limit, but rather problems of an initial design of a niche product that uses off the shelf components.) A previous post here described how a AWS (3G) spectrum-based service could serve upper end users with high density and high audio quality requirements. Yes, it would result in increased costs for spectrum access. But that is the past 20 years of spectrum policy in the US and many other countries.

Finally, one problem the US wireless microphone manufacturers face is that they are relatively small firms with niche markets and do not have a good R&D base or volumes that easily justify custom integrated circuits. Thus they tend to stay with the existing technology and not press the margins to get new products. Thus they also are spending money on lawyers to press the FCC rather than innovating - like the medical telemetry people did when they noticed the same problem with the TV band. Ausio-Technica, as mentioned above, stands out as a recent innovator because they contracted with Multispectral Solutions (MSSI) of Germantown, MD for their new UWB product. They didn't spend all their money on lawyers!

Conservative wireless mic companies watch out! The problem isn't just Docket 04-186, Sony is entering your field too with new technology. Surf over to www.sonybiz.net/go-digital and you will see that Sony believes that digital will work for wireless mics and has entered the UK market. Fortunately for the not so nimble US manufacturers the present Sony models only work in 798-862 MHz and can't be used (legally) in the US market except in a small segment that will disappear in 11 months. But it wouldn't take much to move these to another band other than UHF-TV. Marrying the Sony analog-to-digital conversion technology to 3G/AWS cell phone technology should also be straightforward.

But the key issue is that FCC is not now considering any other options for wireless mics at the moment. The status quo is an inefficient anachronistic use of valuable spectrum and will have real problems next year when the 700 MHz auction winners claim their spectrum.

Possible options that should be examined should include the possibility of opening a new band, other than UHF TV. that is more compatible with sharing with the wireless mic industry as it actually exists today along with use of more efficient technology than the current de facto monoculture of FM. The demands of the wireless mic users that the new spectrum access should have no cost should be considered but should not be treated as a "non-negotiable demand". UK wireless mic users pay for access so there is a relevant precedent. The longer FCC ignores this issue, the more difficult it will become.

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Harold Feld has published an interesting follow up to this post entitled "700 MHz Aftermath: Verizon, AT&T & the $16 Billion Termites"