FCC chair Kevin Martin's support for free public wireless access will create a "trifecta" for public safety wireless communications.
In a surprisingly under-reported declaration, Federal Communications Commission (FCC) Chairman Kevin Martin has come out in support of free wireless broadband nationwide. The Bush administration has not been uniformly against subsidized broadband service. It has provided limited funds via the FCC and the U.S. Department of Agriculture for rural broadband service--mostly of the wireline variety and targeted toward health care services. However, this wireless broadband would be provided via a set-aside from the spectrum operated by private providers of wireless service. This is well within the purview of the FCC's authority since the finite electromagnetic spectrum is regulated by the FCC as a public resource not unlike forests or waterways.
At any rate, the implications of this high-profile declaration are significant for public sector information and communications technology in the area of public safety. The FCC has already set aside spectrum for public safety wireless interoperability. While the FCC has struggled to gain interest in developing this thin slice of spectrum, it will continue to reformulate its approach until it finds the right incentives. Furthermore, the digital TV transition will ensure that virtually all American households will eventually have TVs capable of receiving detailed public safety messages. Free wireless spectrum could be harnessed during emergencies to ensure two-way communications with populations on the move without reliable access to TVs or wireline broadband. Low-income households have shown much more interest in spending their limited dollars on mobile communications than home broadband. During a crisis, it's to everyone's advantage (regardless of income level) that the maximal amount of coordination be achieved.
Industry resistance to this new set aside is sure to be strong in the short term, but--merely by putting the option on the table in a high profile way--Chairman Martin has instigated a discussion that will have long-term impact.
A high-altitude nuclear detonation produces an immediate flux of gamma rays from the nuclear reactions within the device. These photons in turn produce high energy free electrons by Compton scattering at altitudes between (roughly) 20 and 40 km. These electrons are then trapped in the Earth's magnetic field, giving rise to an oscillating electric current. This current is asymmetric in general and gives rise to a rapidly rising radiated electromagnetic field called an electromagnetic pulse (EMP). Because the electrons are trapped essentially simultaneously, a very large electromagnetic source radiates coherently.
The pulse can easily span continent-sized areas, and this radiation can affect systems on land, sea, and air. The first recorded EMP incident accompanied a high-altitude nuclear test over the South Pacific and resulted in power system failures as far away as Hawaii. A large device detonated at 400–500 km (250 to 312 miles) over Kansas would affect all of the continental U.S. The signal from such an event extends to the visual horizon as seen from the burst point.
Thus, for equipment to be affected, the weapon needs to be above the visual horizon. Because of the nature of the pulse as a large, long, high powered, noisy spike, it is doubtful that there would be much protection if the explosion were seen in the sky just below the tops of hills or mountains.
The altitude indicated above is greater than that of the International Space Station and many low Earth orbit satellites. Large weapons could have a dramatic impact on satellite operations and communications; smaller weapons have less such potential.