Modeling Multiple HF Antennas on the C-130/Hercules Aircraft - Part I
Abstract
Transport aircraft such as the C-130/Hercules need a long range HF communications system. There is also an interest in dual HF systems using two separate antennas, in a SIMOP mode: one transmitting and the other receiving at arbitrary frequencies over the 2-30 MHz HF frequency range. Candidates for these HF antennas are probes on the vertical stabilizer or the wingtips and dorsal or wing-root notch antennas. This paper reports on the computer modeling of these candidate antennas with NEC4 and the Galerkin MBC computer code. In this initial paper, the comparative results are presented for the impedance of each antenna and for the classic 'HF Performance Parameters', from spectral sweeps carried out in 0.1 MHz steps over the entire HF band. At selected frequencies, current distributions and volumetric radiation patterns are presented in order to understand the peaks and variations in the plots of impedance and in the performance parameters. Appreciation of performance of the candidate antennas is an essential first step. The current distributions on the model for each antenna begin to indicate the degree of antenna coupling that might be expected between the antennas for SIMOP operation. Explicit coupling analysis to determine voltages at passive antennas due to transmission on any one of the others will be presented in a subsequent paper. Thus the CEM analysis provides a special powerful "virtual antenna range" wherein individual performance and SIMOP antenna features can be determined. Validation of the results is based on previous CEM modeling and corresponding measurements, inter-code comparisons and the self-consistency of the results.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2004
- Accession Number
- ADA438044
Entities
People
- Anita K. Lau
- Christopher W. Trueman
- David Gaudine
- Stanley J. Kubina
Organizations
- Concordia University