ORIENTATION MEASUREMENTS IN THAILAND WITH HF DIPOLE ANTENNAS FOR TACTICAL COMMUNICATION
Abstract
The magneto-ionic theory is described with a view to optimizing the orientation of a linearly polarized antenna such as half-wave dipole for short- range communication via the ionosphere near the geomagnetic equator. The practical application, together with its limitations, is also considered. Continuous-wave measurements, performed with the goal of determining a suitable wave mode of propagation and hence the desired orientation of horizontal dipoles, demonstrate the superiority of the ordinary wave (north-south dipoles) for overall performance over a major part of the day when communication traffic is normally active. The coupling between the ordinary and the extraordinary modes is studied and the stability within a particular mode of propagation is discussed, together with its susceptibility to atmospheric noise. Pulse measurements confirm the results of the CW measurements and give additional information on the amplitude and phase stability of received waves, and on ionospheric layers supporting these waves. The overall results of the CW and pulse tests suggest that, although the optimum orientation of horizontal dipoles for both transmission and reception is parallel to the earth's magnetic field, communication performance may be further improved by orientation diversity reception. The overall results of this study produce a simplified method of planning antenna configurations for tactical HF communication in Thailand.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1967
- Accession Number
- AD0675460
Entities
People
- Paibul Nacaskul
Organizations
- SRI International