Accession Number : ADP006311

Title :   Probing the Ionosphere with the University of Illinois Sounder,

Corporate Author : ILLINOIS UNIV AT URBANA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING

Personal Author(s) : Lin, K. H. ; Schlegl, W. S. ; Yang, K. S. ; Yeh, K.C.

Report Date : 03 MAY 1990

Pagination or Media Count : 20

Abstract : The University of Illinois has recently deployed an HF oblique sounder, the purpose of which is to probe the ionosphere for wideband response. The sounder is capable of operations in two modes: ranging mode and probing mode. Under the ranging mode, group delay measurements are made using phase modulated PN codes. Such measurements can assist the determination of propagation mode and help the data interpretation. Under the probing mode, a comb of CW signals across the band of interest are sent to probe the ionospheric response. The transmitter is located at Platteville, Colorado and toward the east at approximately one-hop distance is the receiver located at Urbana, Illinois. Within the frequency range of 5 to 15 MHz, the transmitter is designed to synthesize up to six discrete frequencies selectable among a possible eight hundred each separated from its neighbor by 12.5 kHz for probing measurements. Up to a total power of 200 W can be fed to a transmitting antenna which is a log-periodic array consisting of 18 elements above a ground screen.

Descriptors :   *IONOSPHERIC MODELS, *ATMOSPHERIC SOUNDING, PSEUDO NOISE SYSTEMS, HIGH FREQUENCY, RADIO SIGNALS, IONOSPHERIC PROPAGATION.

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE