ALTAIR: An incoherent scatter radar for equatorial spread-F studies

In this report, we present preliminary results obtained from data collected with ALTAIR, a high-power VHF/UHF radar, during the Wideband Equatorial Program. The Wideband Equatorial Program is a coordinated field program sponsored by the Defense Nuclear Agency (DNA) to study the physical processes underlying the production of intense field-aligned irregularities and the effects of those irregularities on satellite communication channels that operate in the gigahertz frequency range. This radar is sensitive enough for incoherent-scatter measurements as well as being capable of spatially mapping E and F region irregularities as a function of time. With data collected from the operation of ALTAIR in a sector scan mode it is possible to determine the spatial distribution of 1-m spread-F irregularities and their dynamics, and to relate them to the parameters of the background equatorial ionosphere. These relationships provide a means of critically evaluating proposed source mechanisms of equatorial spread-F.