Accession Number:

AD0276157

Title:

AN EXPERIMENTAL INVESTIGATION OF EM WAVE PROPAGATION AT 400 CPS

Descriptive Note:

Corporate Author:

SPACE-GENERAL CORP EL MONTE CALIF

Personal Author(s):

• DUNN,G.R.

Report Date:

1962-04-02

Pagination or Media Count:

1.0

Abstract:

An investigation of extremely low frequency ELF electromagnetic wave propagation was undertaken utilizing a stable source of 400 c power. This method has the ability to define the propagation law, determine attenuation rates, study path variations, and provide knowledge regarding coupling to the medium. During Sept. and Oct. 1961, field strength measurements were made up to 760 mi. from the transmitter. The dependence of magnetic field intensity on range is substantially in accord with the mode theory in which only the zero order mode is considered. The nighttime data points agree best with the sharply bounded ionosphere model with an attenuation rate of 2.3 db1000 km. The daytime data indicates the attenuation rate is 6.0 db1000 km. This higher absorption is explained by assuming an exponential ionosphere model. The amplitude probability distributions of 400 c atmospheric noise are similar to those in the VLF band. The median rms value of the vertical electric noise field during the test period was 100 microvoltmeter in a 40-c band. A description of the equipment and a discussion of the horizontal grounded radiator, are included. Author

Descriptors:

• *ELECTROMAGNETIC RADIATION
• *WAVE PROPAGATION
• ANTENNA RADIATION PATTERNS
• ATMOSPHERE MODELS
• ATMOSPHERICS
• ATTENUATION
• AUDIO FREQUENCY
• DIPOLE ANTENNAS
• ELECTRICAL CONDUCTIVITY
• ELECTRICAL IMPEDANCE
• EXTREMELY LOW FREQUENCY
• FREQUENCY SHIFT
• IONOSPHERE
• LOOP ANTENNAS
• MATHEMATICAL ANALYSIS
• MOBILE
• NOISE(RADIO)
• NOISE ANALYZERS
• PROPAGATION
• RADIO INTERFERENCE
• RADIO RECEIVERS
• RADIO TRANSMITTERS
• SOILS
• TEST EQUIPMENT
• TEST METHODS

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE