4. 4. Wireless Systems in the Post-DTV Transition Era

In the United States, the Federal Communications Commission (FCC) has been supervising the transition of broadcast television from its traditional analog format to an all-digital format (DTV). In the process, the commission has also been mandated to increase efficient use of TV spectrum and to increase the amount of spectrum available for public safety and other wireless services.

Therefore, the transition has provided both consolidation of the broadcast spectrum and the reallocation of the resulting open spectrum for other uses. The FCC has consigned all broadcast television into a "core" band, TV Channels 2-51. All existing TV stations above Channel 51 have migrated into the core band. The upper frequency limit of the broadcast band is now 698 MHz and (nearly) all full-power TV stations are now digital. All former television spectrum above Channel 51 (698-806 MHz) has now been reallocated for new services.

This spectrum is generally referred to as the “700 MHz” band. Within the 700 MHz band, most of this spectrum has been auctioned by competitive bidding to telecommunications companies while the rest has been set aside for public safety services. The telecommunications spectrum, 698-763 MHz (roughly TV 52-62) and 775-793 MHz (roughly TV 65-67), is being developed for various services such as broadband internet access, streaming video, and other digital data transmission. The public safety bands total 24 MHz in two "paired" bands: 763-775 MHz (roughly TV 63-64) for fixed transmitters and 793-805 MHz (roughly TV 68-69) for mobile transmitters.

For both statutory and practical reasons, the 700 MHz band is no longer available for use by wireless microphones or other wireless systems. Not only will they no longer be authorized in this spectrum, but also the interference from new services in this band will make operation of such systems unreliable at best. For this reason, manufacturers and distributors of wireless systems in the US market are no longer supplying wireless systems in the 700 MHz band. New wireless systems continue to be available mainly in the core television band (TV 2-51) and in a few other narrow frequency bands.