Location of Repository

The propagation of VHF and UHF radio waves over sea paths

By Chow Yen Desmond Sim

Abstract

This thesis is concerned with the statistical studies of VHF/UHF radio wave propagation over the sea path at the limits of line-of-sight range. The objective is to provide a set of data that leads to the understanding of the characteristic of VHF/UHF radio wave over the sea path. A series of experiments were conducted using two paths of around 33 and 48 km across the English Channel. These two paths are between fixed land-based locations that provide an unobstructed condition. This allows a prolonged period of data collection under several sea states and atmospheric conditions without the heavy expenses of ship borne trial.\ud The statistic studies showed that the high signal strength variation observed at both receiving sites are the results due to ducting and super-refraction. It occurred around 43 to 76% and 31 to 48% of the total time (percentage of days) during summer 2001 and 2002 respectively. In comparison, the total time was below 10% during winter period. Across the Jersey-Alderney path (48 km), high fading phenomenon was observed which is a result due to interference fading between the diffracted and troposcattered signal.\ud The statistics showed that it occurred at around 35 to 55% of the total times during summer with an average fading range of around 10 and 7 dB during autumn and summer respectively, with an average fading period of around 7 seconds.\ud The results from simulation showed that when the VHF/UHF signal reaches the radio horizon, the dominant propagating mechanism is smooth earth diffraction. Beyond the radio horizon, the attenuation rate increases dramatically and at a certain distance (depending on the frequency, antenna height and seasonal condition), the diffracted signals will be weaken and the troposcatter effect will become the dominant propagating mechanism

Publisher: University of Leicester
Year: 2002
OAI identifier: oai:lra.le.ac.uk:2381/7444

Suggested articles

Preview

Citations

  1. (1966). A survey of UHF Propagation Measurements carried out by the BBC”.
  2. (1997). C.P.: “Mearsurements of non line-ofsight VHF propagation over the sea surface”.
  3. (1985). Comparison of Evaporation duct and Path Loss model”, doi
  4. (1972). Earth and Radio. An introduction to the ionosphere and magnetosphere”. doi
  5. (1979). Effects of the troposphere on radio communication”.
  6. (1962). Electromagnetic Waves in Stratified Media”. doi
  7. (1978). Evaporation Duct Measurements in the mid-Atlantic”,
  8. (1990). Evapotranspiration and Irrigation Water Requirements”. doi
  9. (1985). G.B.: “Tropospheric Radio Wave Propagation”. doi
  10. (1969). Introduction to Ionospheric Physics”. doi
  11. (1969). Ionospheric Radio”. Peter Peregrinus Ltd,
  12. (2001). ITU-R Recommendation P.453-8: “The radio refractive index: its formula and refractivity data”.
  13. (2001). ITU-R Recommendation P.526-7: “propagation by diffraction”,
  14. (1996). Kallisto Users Guide, Greening technology
  15. (1974). Microwave Mobile Communication”. doi
  16. (2000). N.C.: “Measurement of Doppler Spread on
  17. (2000). Parabolic equation methods for electromagnetic wave propagation”. The institution of Electrical Engineerings, doi
  18. (1985). Practical Application of an Evaporation Duct Model.” Radio Science, doi
  19. (1982). Propagation effects on radio range and noise in earth-space telecommunications”. doi
  20. (1996). Propagation of Radiowave”. doi
  21. (1977). Radio Propagation for Vehicular Communications”. doi
  22. (1961). Radio Wave in the Ionosphere”. doi
  23. (2000). Radio wave propagation - principle and techniques”.
  24. Radio Wave Propagation and Antennas, An Introduction”.
  25. (1963). Radio Wave Propagation and the Ionosphere”. Consultants Bureau, doi
  26. (1965). Radio Wave Propagation V.H.F And Above”. Chapman and Hall Ltd.,
  27. (1974). Radio Wave Propagation”, doi
  28. (1972). Radio-Wave propagation measurements over sea water”. Harry Diamond Laboratories,
  29. (1974). RadioWave Propagation in the Evaporation Duct”, The Marconi Rev.,
  30. (1976). Refraction effects in the neutral atmosphere”. Methods of Experimental Physics, Vol.12, Astrohysics, Part B: Radio Telescopes (M.L.Meeks, cd.), doi
  31. (1959). Simple methods for computing tropospheric and ionospheric refractive effects on radio waves”. doi
  32. (1965). Simultaneous long distance tropospheric propagation measurements at 560 and 774 MHz over the North Sea”. doi
  33. (1989). The Earth’s Ionosphere, Plasma Physics and Electrodynamics.” doi
  34. (2000). The mobile Radio Propagation Channel”, 2nd edition, doi
  35. (1973). The Occurrence of Very High Field at beyond the Horizon Propagation Over Sea doi
  36. (1992). The VHF/UHF Book”. doi
  37. (1988). Troposcatter Radio Links”,
  38. (1966). Tropospheric Radio wave Propagation beyond the Horizon”. doi
  39. (1979). UHF Signal Strength Measurement as a guide to Atmospheric Structures”,
  40. (1966). Ultra High Frequency Propagation”, Chapman and Hall Ltd., pg. 1-12, chapter 3–5,

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.