title: Early ITU model
text: # Early ITU model
  
  The ITU vegetation model is a radio propagation model that estimates the path loss encountered due to the presence of one or more trees inside a point to point telecommunication link. The predictions found from this model is congruent to those found from Weissberger’s modified exponential decay model in low frequencies.
  
  ## History
  
  The CCIR, predecessor of ITU, adopted this model in the late 1986.
  
  ## Applicable to/under conditions
  
  * This model is applicable on the situations where the telecommunication link has some obstructions made by trees along its way
  * This model is suitable for point-to-point microwave links that has a vegetation in their path.
  * Typical application of this model is to predict the path loss for microwave links.
  
  ## Coverage
  
  Frequency: Not specified
  
  Depth of Foliage: Not specified
  
  ## Mathematical formulation
  
  The model is formulated as:
  
  $L=0.2\,f^{0.3}\,d^{0.6}$
  
  Where
  
      L = The path loss. Unit: decibel (dB)
      f = The frequency of transmission. Unit: megahertz (MHz)
      d = The depth of foliage along the link: Unit: meter (m)
  
  ## Points to note
  
  This equation is scaled for frequency specified in megahertz (MHz).
  
  The depth of foliage must be in the units of meters.
  
  ## Limitations
  
  The results of this model gets impractical at high frequencies.
  
  