Satellite Communications
geosynchronous equatorial ~36,000 km, <=180
- C band, 3.7-4.2 GHx down, 5.9-6.4 GHz up
- Ku band, 11.7-12.2 down, 14.0-14.5 up
- Ka band 17.7-21.7 down, 27.5-30.5 up
- typical sattelite ~ 12-20 transponders
- round trip transit time ~ 300 ms
- VSAT is 2 trips using hub ~ 540 ms
low orbit satellite ~750 Km, - LEO
- Iridium - 77 (now 66), 6 polar orbits (big atom)
- voice, data, paging, fax, navigation worldwide
- 1628 mobile cells, 174 full duplex channels each
- L band 1.6 GHz, 200MHz total bandwidth
- competes with PCS