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Proceedings Paper

Near earth propagation study
Author(s): R. Wert; A. Goroch; D. Tremper; L. Schuette; D. Wendland
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Paper Abstract

Networks of small ground sensors and other near earth devices deployed in the battlefield are postulated to be of considerable value to the future warfighter. The radio frequency (RF) link between devices will dictate the resilience of the network in communicating critical information in the battlespace. A prior knowledge of the RF environment inches above the ground is required to properly design the sensor network. Signal strength was measured with antennas at 4, 7, and 120 inches above the ground over a range of 10 to 400 feet. The source consisted of a 1780 MHz, 1/4 watt transmitter feeding a quarter wave vertical monopole. The receive equipment consisted of a corner reflector monopole, spectrum analyzer and data logger program. Data points were taken at 10-foot increments over the 400-foot range. The received signal, at heights of 4 and 7 inches, were compared to the measurements taken at a height of 120 inches (close to “free space”). It was found that there is a significant increase in path loss as the antenna approached the ground. There was a 15 dB increase in path loss from when the antennas were at 120 inches to 7 inches off the ground and 18 dB increase in path loss with the antenna 4 inches off the ground. Variations in path loss (10 dB) over time (seconds) were also noted.

Paper Details

Date Published: 26 May 2005
PDF: 9 pages
Proc. SPIE 5820, Defense Transformation and Network-Centric Systems, (26 May 2005); doi: 10.1117/12.602846
Show Author Affiliations
R. Wert, Naval Research Lab. (United States)
A. Goroch, Naval Research Lab. (United States)
D. Tremper, Naval Research Lab. (United States)
L. Schuette, Naval Research Lab. (United States)
D. Wendland, ITT Industries/Naval Research Lab. (United States)


Published in SPIE Proceedings Vol. 5820:
Defense Transformation and Network-Centric Systems
Raja Suresh, Editor(s)

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