Accession Number:

ADA110671

Title:

VLF/LF Long Wave Propagation Study

Descriptive Note:

Final technical rept.

Corporate Author:

MEGAPULSE INC BEDFORD MA

Report Date:

1981-11-01

Pagination or Media Count:

142.0

Abstract:

A program of ARCAS rocket measurements provided field strength data from 0 to 75 km altitude, in both Transverse Magnetic TM and Transverse Electric TE polarizations. Sky wave parameters related to survivable ground wave communications were measured at a frequency of 100 kHz, and a method of communicating with short ground wave pulses was demonstrated on a 230 km propagation path. Measurements were made in New York state, and in Brazil, to further define the nature of pulse reflections from ionospheric heights below the classical D-region. Instrumentation was developed to detect small changes in 100 kHz ground wave propagation velocity which might correlate with tropospheric conditions. Preliminary mechanical considerations indicate that it might be possible to deploy long center-fed dipole antennas from an earth satellite. The program of high-resolution ionosounding with TM pulses in Greenland was augmented by transmitting TE pulses from an unused powerline at Thule Air Base. It was demonstrated that the effects of ionospheric disturbances can now be observed simultaneously with both polarizations. Input resistances and reactances of the powerline antenna were measured as functions of frequency in preparation for a follow-on program of long range propagation tests.

Subject Categories:

  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE