Satellite Communications

• HISTORY

  Sputnik (1957), Explorer (1958), Intelsat, Comsat, ... INSAT

• Geo-Stationary Orbit (35,680 km.)

  Footprint (30% of Earth's surface)

• Low-orbit (Iridium, Inmarsat)

  Rotating Antenna, Out of range?

• Frequency Bands (Transponders)

  	Uplink (GHz)	Downlink	Bandwidth
  C	5.9-6.4	3.7-4.2	500 MHz
  K$_u$	14-14.5	10-11.2	500 MHz
  K$_a$	27.5-31.0	17.7-21.2	3.5 GHz

• C band clashes with terrestrial radio
• K$_u$ band affected by rain (dampening)