Accession Number : ADA135830

Title :   Wireless Communication Systems.

Descriptive Note : Final rept. 5 May 80-22 Dec 82,


Personal Author(s) : Papadopoulos,D. ; Chang,C. L. ; Ko,K. ; Reiman,A. ; Tripathi,V.

Report Date : 01 DEC 1983

Pagination or Media Count : 90

Abstract : The feasibility for producing ELF signals in the earth ionospheric waveguide, by downconverting H.F. pump power in the ionospheric plasma has been investigated. We have found that: (i) Interaction regions of horizontal width approx. 100km, localized inside an ionospheric density gradient, can deplete the pump for pump powers above a threshold value. Minimum threshold is achieved for pumps propagating almost perpendicular to the density gradient (very oblique incidence) at 100 km altitude. The threshold power required is between 3-10 MW of H.F. (ii) The conversion efficiency from H.F. to ELF in the ionosphere could reach values of the order of 0.01. (iii) The scheme can operate either as an ELF generator if we use an H.F. pump with power 3-10 MW and a lower H.F. sideband with power 100 kw, or as an amplifier of ELF signals from weak ground transmitters (such as the Wisconsin test facility), or from weak space or balloon based antennas. A variation of the scheme can operate as a broadband ELF generator for jamming purposes. (Author)

Descriptors :   *Pumping(Electronics), *Radiofrequency power, *Plasmas(Physics), *Ionospheric disturbances, *Radio jamming, *Radiofrequency amplifiers, Antennas, Radio transmitters, Very low frequency, Extremely low frequency, High frequency, Radio signals, Horizontal orientation, Threshold effects, Balloons, Width, Generators, Conversion, Broadband, Interactions, Pumps, Ionosphere, Gradients, Density, Signals, Amplifiers, Wisconsin, Gain

Subject Categories : Atmospheric Physics
      Radio Countermeasures

Distribution Statement : APPROVED FOR PUBLIC RELEASE