Frequency Diversity for UHF Telemetry

Abstract

The use of frequency diversity to allow substantial airborne antenna simplification for L and S band telemetry is described. The system is particularly useful on large, spin stabilized vehicles where omni-directional antenna coverage is required. Typical antenna patterns with and without diversity are presented. A systems block diagram showing dual receivers and diversity combiner is also described. A weight tradeoff is presented for diversity versus non-diversity, with vehicle diameter (at the antenna location) as the variable. It is shown that, at S band, for diameters in excess of about 5 in., frequency diversity represents a favorable approach.