Radio observations of the cosmos are gathered by geoscientists using complex earth-orbiting satellites and ground-based equipment, and by radio astronomers using large ground-based radio telescopes. Signals from natural radio emissions are extremely weak, and the equipment used to measure them is becoming ever-more sophisticated and sensitive. The radio spectrum is also being used by radiating, or "active," services, ranging from aircraft radars to rapidly expanding consumer services such as cellular telephones and wireless internet. These valuable active services transmit radio waves and thereby potentially interfere with the receive-only, or "passive," scientific services. Transmitters for the active services create an artificial "electronic fog" which can cause confusion, and, in severe cases, totally blinds the passive receivers. Both the active and the passive services are increasing their use of the spectrum, and so the potential for interference, already strong, is also increasing. This book addresses the tension between the active services' demand for greater spectrum use and the passive users' need for quiet spectrum. The included recommendations provide a pathway for putting in place the regulatory mechanisms and associated supporting research activities necessary to meet the demands of both users.

More intensive use of spectrum would meet existing and potential demand and could be the basis for unprecedented economic growth.

In 2003, the Department of Commerce's Spectrum Policy Initiative was established with the objective of promoting a more efficient and beneficial use of the spectrum. As part of that Initiative, a series of public forums about spectrum management policy was held. The Computer Science and Telecommunications Board was asked to organize one of these forums, a public forum to gather the views of a variety of government and private sector stakeholders about the impact of spectrum policy on their activities. This report presents a summary of those views. Among those included are those representing national defense, homeland security, aviation, science, public safety, amateur radio, cellular voice and data, and terrestrial broadcast uses of the spectrum. Although prepared by the NRC, the report does not present NRC findings or recommendations. A broader study of spectrum policy, including findings and recommendations, will be issued in early 2005.

Radio frequency spectrum enables vital wireless communications services used by the federal gov¿t., businesses, and consumers. Spectrum capacity is necessary for wireless broadband (high-speed Internet access) and broadband deployment will boost the nation's capabilities in many important areas. As the demand for spectrum continues to increase, there is concern about adequate access to meet future needs. This report examines: (1) how the Nat. Telecomm. and Info. Admin. (NTIA) is managing spectrum needs of federal agencies; (2) how federal agencies are using and managing assigned spectrum; and (3) what steps NTIA has taken to meet recent initiatives aimed at making spectrum available for broadband. Illus. This is a print on demand report.

Active remote sensing is the principal tool used to study and to predict short- and long-term changes in the environment of Earth - the atmosphere, the oceans and the land surfaces - as well as the near space environment of Earth. All of these measurements are essential to understanding terrestrial weather, climate change, space weather hazards, and threats from asteroids. Active remote sensing measurements are of inestimable benefit to society, as we pursue the development of a technological civilization that is economically viable, and seek to maintain the quality of our life. A Strategy for Active Remote Sensing Amid Increased Demand for Spectrum describes the threats, both current and future, to the effective use of the electromagnetic spectrum required for active remote sensing. This report offers specific recommendations for protecting and making effective use of the spectrum required for active remote sensing.