FULL-SCALE HF ANTENNA PATTERN MEASUREMENTS MADE WITH TRANSMITTER TOWED BY AIRCRAFT
STANFORD RESEARCH INST MENLO PARK CA
Pagination or Media Count:
The radiation pattern of a large antenna over an irregular ground plane of uncertain conductivity is generally difficult or impossible to calculate the unknown ground losses also complicate the use of modeling techniques. It therefore becomes necessary to make full -scale measurements in the field. If it is necessary to know the radiation pattern for angles above the horizon, the use of an airplane or helicopter is indicated. Of the various flight paths that can be visualized, those convenient to use in practice are vertical descents, straight overhead runs, straight fly-by runs that do not go overhead, and circular paths around a fixed ground point. This memorandum deals with a method of making flight tests using the latter plan, an airplane flying around the unknown ground antenna on a circular path while transmitting a constant signal. Receiving equipment on the ground records the voltage induced at the antenna terminals as a function of azimuth angle from this information the antenna pattern which is the same for either transmitting or receiving can be plotted.
- Electrical and Electronic Equipment
- Test Facilities, Equipment and Methods