• Compute length of the line-of-sight.
  d ²+ (h_t-h_r)² = 1,000,784.
  Taking the square root gives the length: 1000.3919 meter

• Compute length of the ground reflected wave.
  d ²+ (h_t-h_r)² = 1,001,024.
  Taking the square root gives the length: 1000.5119 meter

• Compute the phase difference due to path length differences.

  
  1000.5119 meter - 1000.3919 meter = 0.12 meter
  At a wavelength l = c / f = 0.3 meter, this phase difference corresponds to 0.4 l, or 144 degrees.

JPL's Wireless Communication Reference Website © Jean-Paul M.G. Linnartz, 1999.