Observation of ionospheric modification using high power oblique HF transmissions. Scientific report No. 1

Technical Report · Mon Jun 01 04:00:00 EDT 1992

OSTI ID:7065115

Sales, G S; Huang, Y

A series of experiments were carried out during late May 1991 to investigate changes produced in the ionosphere by a high power HF transmitter operating at a frequency approximately two times the F-layer critical frequency. These high power oblique transmissions heated a region of the ionosphere some 1200km east of the Delano, CA Voice of America relay station, operating with an effective radiated power of 90 dBW. An HF probe signal was used to detect changes in the ionosphere as it passed through the modified region. The probe system, operating at a frequency very close to the heater frequency, frequently showed amplitude changes that correlate well with the ten minute on/off cycling of the high power transmitter. This preliminary study used several signal processing methods to detect these changes in the presence of strong polarization fading. The results indicate that the amplitude of the probe signal decreased by 2 to 3 dB, often within 15 to 30s after the high power transmitter was turned on.

• Research Organization: Massachusetts Univ., Lowell, MA (United States). Center for Atmospheric Research
• OSTI ID: 7065115
• Report Number(s): AD-A-258706/1/XAB; CNN: F19628-90-K-0039
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
661320 -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMPLIFIERS
COMMUNICATIONS
CRITICAL FREQUENCY
DETECTION
DEVELOPED COUNTRIES
EARTH ATMOSPHERE
ELECTRONIC EQUIPMENT
EQUIPMENT
F REGION
HIGH FREQUENCY AMPLIFIERS
IONOSPHERE
IONOSPHERIC EFFECTS
NORTH AMERICA
PLANETARY IONOSPHERES
POLARIZATION
POWER GENERATION
USA
WAVE PROPAGATION