AN/FPS-95 Research and Development Program (Final Technical Report, Naval Research Laboratory, Long-Path One-Way Propagation Effects)
NAVAL RESEARCH LAB WASHINGTON DC
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Reciprocal tests were run between the U.K. and a station on Cyprus to measure 1 the dynamic range constraints imposed by a one-way ionospheric path between two points in over-the-horizon HF propagation, and 2 possible ANFPS- 95 antenna andor ground screen noise sources in transmission or reception which are not excitable by line-of-sight measurements. Results indicate that the ionosphere presents no source of noise as a transmission medium for low elevation angles 3 to 5 elevation, within the capabilities of the transmitting and receiving equipment used. The noise limitations measured in the ANFPS-95 receive tests were -77 dB and -85 dB, mean noise levels in a two-Hertz bandwidth centered at 5 and 18 Hertz, respectively, from the spectrum peak. These levels are thought to be skirts of the transmitted spectrum, although line-of-sight monitoring by the test van could not conclusively verify this because of local aircraft contamination of signal. On the reciprocal path test, in which a receiverprocessor test van measured the ANFPS-95 transmission, the received signal was clean 80 to 83 dB from spectrum peak across 4 to 12 Hertz from the spectrum peak.
- Antimissile Defense Systems
- Active and Passive Radar Detection and Equipment