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The measurement of the phase velocity of ground-wave propagation at low frequencies over a land path

The measurement of the phase velocity of ground-wave propagation at low frequencies over a land path

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The paper describes the measurement of the change of phase with distance of a 127.5-kc/s wave over a particular inhomogeneous land path and the deduction of the mean velocity.The measuring system made use of transmissions from stations of the English chain of the Decca Navigator System, and the path studied was that between the Lewes (Sussex) and Warwick stations (177 km). With the aid of a mobile phase-measuring equipment the difference between the phase of the signal from one transmitter and that of the signal from the other transmitter was measured with an accuracy of 0.25° at 25 points along the path. From these results and a knowledge of the exact position of the points it was possible to plot a curve showing the deviation of the measured phase from that calculated on the assumption of a velocity equal to that in free space.The mean velocity deduced for the path was 299 230 ± 12 km/sec.An examination was made of the measured change of phase along the path in relation to the profile and geological structure. Although there was no definite evidence of the phase of the wave being affected by the ground contours, the influence of the nature of the soil was very marked. A detailed study of the geological structure was undertaken and the electrical characteristics of each section of the path were assessed. A high velocity over ground of good conductivity and a low velocity over ground of poor conductivity was clearly shown.Comparisons between the measurements and the phase changes derived by a method based on theoretical curves of phase lag over homogeneous ground showed good correlation. They also confirmed the theoretical predictions of a characteristic phase disturbance at the boundary between sections of differing conductivity. It is concluded that this method of phase determination over an inhomogeneous path is one which offers a good approximation to the phase changes actually taking place.

References

    1. 1)
      • G. Millington , G.A. Isted . Ground-Wave Propagation over an Inhomogeneous Smooth Earth. Part 2. Experimental Evidence and Practical Implications. Proceedings I.E.E.
    2. 2)
      • H. Bremmer . (1949) , Terrestrial Radio Waves.
    3. 3)
      • R.H. Barfield . Some Measurements of the Electrical Constants of the Ground at Short Wavelengths by the Wave-Tilt Method. Journal I.E.E.
    4. 4)
      • R.L. Smith-Rose . Electrical Measurements on Soil with Alternating Currents. Journal I.E.E.
    5. 5)
      • W. Ross , E.N. Bramley , G.E. Ashwell . A Phase Comparison Method of Measuring the Direction of Arrival of Ionospheric Radio Waves. Proceedings I.E.E.
    6. 6)
      • B.G. Pressey , C.S. Fowler , R.W. Mason . A Precision Phase Comparator for Use at Low Radio Frequencies. Proceedings I.E.E.
    7. 7)
      • K.A. Norton . Propagation of Radio Waves over the Surface of the Earth and in the Upper Atmosphere. Proceedings of the Institute of Radio Engineers
    8. 8)
      • Calculation of Ground-Wave Field Intensity over a Finitely-Conducting Spherical Earth. Proceedings of the Institute of Radio Engineers
    9. 9)
      • L.G. Reynolds . An Examination of Some Site and Transmission-Path Errors of the Decca Navigator System when used over Land. Proceedings I.E.E.
    10. 10)
      • E.B. Mendoza . A Method of Determining the Velocity of Radio Waves over Land on Frequencies near 100 kc/s. Journal I.E.E.
    11. 11)
      • The Decca Navigator System. Engineering
    12. 12)
      • A.B. Schneider . Phase Variations with Range of the Ground-Wave Signal from C.W. Transmitters in the 70–130 kc/s Band. Journal of the British Institution of Radio Engineers
    13. 13)
      • `Electrical Resistivity Map of England and Wales', Ref. M/T 32, E.R.A. Report, .
    14. 14)
      • R.L. Smith-Rose . The Speed of Radio Waves and its Importance in Some Applications. Proceedings of the Institute of Radio Engineers
    15. 15)
      • G. Millington . Ground-Wave Propagation over an Inhomogeneous Smooth Earth. Proceedings I.E.E.
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