VLF/LF Long Wave Propagation Study
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1981
- Accession Number
- ADA110671
Entities
People
- James B. Donohoe
- Peter Ver Planck
- Royce C. Kahler