DTIC ADA269684: Evaporation Duct Communication. Measurement Results pdf

DTIC ADA269684: Evaporation Duct Communication. Measurement Results

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Results from an experiment to evaluate the performance of an overwater, over-the-horizon, SHF digital communication system are presented. Two simplex microwave digital communication circuits (similar to commercial line-of- sight microwave links) are used on an 83-km transmission path that is twice the line-of-sight distance. One circuit is operating at 7.5 GHz. The other circuit operates at 14.5 GHz. Both transmitters output a quasi-random bit stream at 1. 544-megabits-per-second (DS-1) that is analyzed at the receiver site. In a standard atmosphere, the expected received signal level (RSL) is approximately 60 dB below the receiver threshold. However, at these frequencies, propagation modeling shows that, more than half of the time, trapping by the evaporation duct can increase RSL by at least 60 dB. The propagation path is instrumented at both ends to record surface meteorological conditions and RF characteristics. RSL measurements are compared to predicted levels which are derived from the measured surface meteorology.

Industry standard digital performance measurements are used to assess the effect of RSL variation on link performance. Additionally, results from high-speed sampling of RSL are made to assist in channel characterization. Super High Frequency Radio, Communications, SHF

• Creator/s: Defense Technical Information Center
• Date: 1/1/1993
• Year: 1993
• Book Topics/Themes: DTIC Archive, Rogers, L T, NAVAL COMMAND CONTROL AND OCEAN SURVEILLANCE CENTER RDT AND E DIV SAN DIEGO CA, *DIGITAL COMMUNICATIONS, *MICROWAVE COMMUNICATIONS, *SUPERHIGH FREQUENCY, *SHIP TO SHIP, VELOCITY, LINE OF SIGHT, OUTPUT, PROPAGATION, MEASUREMENT, SITES, PATHS, TIME SERIES ANALYSIS, MICROWAVES, TIME, SURFACES, SIGNALS, RECEIVERS, DUCTS, SAMPLING, METEOROLOGY, STANDARDS, ATMOSPHERES, CHANNELS, TRANSMITTERS, RADIO EQUIPMENT, RADIO LINKS, VISION, CIRCUITS, RECORDS, EVAPORATION

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