Protection of Ka-band satellite channels against rain fading by spare channels at a lower frequency

Since heavy rain is infrequent, a small number of spare channels at C-band or Ku-band can protect a large number of channels at Ka-band against rain fading if the system is designed to permit switching of links from Ka-band to a lower frequency. The improvement in availability is greatest if it is possible to switch to C-band and if the satellite antenna size for C-band can be increased relative to the size used for Ka-band. Calculations for earth stations in the vicinity of New York and Miami are presented. The improvements achievable by frequency diversity are compared with those achievable by error-correction coding and data rate reduction.