Recently, the FCC auctioned portions of the RF spectrum which may in turn have a potential effect on the operation of wireless microphones in certain frequency bands. There are actually two issues at stake with the existing and proposed legislation regarding the RF spectrum.
They are:

1. Auctioning of the “700MHz band” (698-806MHz). As of February 17 2009, this portion of RF spectrum will be available to be used by the companies that won the auctions, and will no longer be available to Part 74 users.
• At the same time, analog TV stations will shut down and only DTV stations will be in operation. Because the 700MHz band will no longer be available to TV broadcasters, the few that are left will have to move to a lower range.
• Thus, our blocks 27, 28 & 29 will have new (as of yet unknown) transmissions operating, while our blocks 21-26 may have a few new DTV channels when compared to today, depending on the local market.
2. There is effort on the part of consumer products manufacturers and content service providers to allow the “white spaces” (remaining unused spectrum between existing TV transmissions) to be used by unlicensed, low power fixed and mobile devices. A decision has not been made on this issue by the FCC; however, it does appear that some additional spectrum may be lost.
• These new devices will be required by the FCC to employ “Spectrum Sensing” technology that will determine what, if any, other users may be present in the RF spectrum, including TV transmissions and wireless microphone systems, among others.
• As of the most recent testing, the prototype “white space” devices have failed the laboratory and field testing in terms of sensing existing RF carriers.

What This Means

1. At least initially, there will be fewer TV stations in operation overall. This is because today, many stations are running redundant NTSC (analog) and DTV broadcasts. After February, 2009, they will only run their DTV broadcasts. Not only this, but DTV allows for multiple program channels to be embedded within a single DTV broadcast carrier. There is little financial incentive to add transmission channels at this time.
• Please note the tables in the sidebar at right showing some examples of major metro markets and the available white space spectrum now and after February, 2009.
2. Lectrosonics makes high-powered systems, from 50mW to 250mW, with the standard units at 100mW. Thus, we already have a major advantage over systems with low-powered transmitters. Also, most of our transmitters have isolated outputs, thus using higher power, as we do, is not the problem (intermodulation products) as it is with competitor’s units that are not isolated. Bottom line: our systems will operate very well even with a fair amount of broad-band noise.

However, it will not be legal for us (or any manufacturer) to make and sell transmitters above 698MHz following February 17, 2009. In November of 2007, we announced to our dealers that we would cease stocking any transmitters in blocks 27, 28 and 29. However, these blocks will be available only on a special-order, non-returnable basis through the end of 2008. In addition, we have added three blocks at the low end of the spectrum (blocks 470, 19 and 20) so that spectrum lost at the high range can be compensated for on the low end. In addition, we will be adding products in the 944-952MHz range, including Venue, IFB, SM Series, UCR401 and SR.

Conclusions

1. The sky is not falling (remember Y2K?). Wireless mics in the UHF band will not be rendered useless within the next few years. Existing and foreseeable-future wireless mics, particularly those made by Lectrosonics, will be fully operational for years to come. Yes – there may be some challenges but mostly it will be about learning and adapting to the new RF spectrum.
2. Although the FCC requires the 700MHz band to be "vacated' as of February 2009, it is unrealistic to expect that all users of low-powered devices (wireless mics) will stop using their current systems. It is very likely that most wireless mic users in this range will continue to operate illegaly for some time. Licensed, legal, part 74 users such as broadcast stations will have to cease operation in the 700 MHz band. Manufacturers of part 74 devices will have to cease manufacturing, importing, or even shipping units that operate in the 700 MHz band. Commercial development of this band will begin in the large metro areras first, then work its way out to the further reaches of the country, the same way that cellular coverage did in the 1990s.
3. Lectrosonics, will, as required by the FCC, cease manufacturing and selling blocks 27, 28 and 29 for the US market at the end of 2008.
4. No one currently knows what will happen in the 470 to 700 MHz range. If and when the consumer "white space devices" hit the market, the UHF band will be similar in terms of congestion to the way the 2.4 GHz band already is today. In other words, it will be workable with proper planning, good system components and good system design.

Lectrosonics is very concerned about these issues, and we hope to do everything possible to make you aware of what is happening and help you with the transition. If you have any questions, please don’t hesitate to contact us.