A direct method for measuring acoustic ground impedance in long-range propagation experiments

Area of Science:

• Electromagnetics and Wave Propagation
• Geophysics
• Radio Science

Background:

• Accurate ground impedance is crucial for modeling radio wave propagation.
• Conventional methods for measuring ground impedance can be complex and indirect.

Purpose of the Study:

• To introduce and validate a direct method for determining ground impedance.
• To assess the method's performance in both short-range and long-range propagation experiments.

Main Methods:

• The proposed method directly applies the definition of impedance.
• Measurements are taken using signals broadcast during propagation experiments.
• The technique allows for impedance determination at multiple points along the propagation path.

Main Results:

• The direct method showed good agreement with a conventional least-squares method in a 10 m test.
• The method's utility was demonstrated in a 400 m agricultural field propagation experiment.
• The measured impedance values were consistent with previously recorded data for the same field.

Conclusions:

• The direct impedance measurement method is a viable and effective technique.
• This approach simplifies ground impedance assessment in propagation studies.
• The method offers a practical tool for geophysical and radio science applications.