Radio Noise from the Ground
Joachim Köppen Kiel June 2021

Some brief explanations

• When an antenna is pointed below the horizon, to the ground, it receives radio noise not only from the soil (marked green) which emits thermal radiation corresponding to its temperature T_GND, but also from the sky noise which is reflected by the ground - shown in red.
  
• ... TBD ...
• Ranges of validity:
  Soil model (from Ulaby & Long): density 0.1 .. 3 g/cm3, temperature 0 .. 40 C, water content 0.1 .. 60 % in volume, frequency: 0.3 .. 20 GHz
  Atmospheric attenuation (from ITU-R P.676-10 for 1013 hPa, 15 C, 7.5 g/cm3 water vapour density): frequency 1 to 100 GHz
  Water (from Meissner & Wentz 2004): temperature -20 .. +40 C, frequency < 500 GHz
  Sea Water (from Meissner & Wentz 2004): temperature -2 .. +29 C, salinity 0 .. 40 ppt, frequency < 90 GHz