Propagation Delay
A satellite phone connects to orbiting satellites instead ofterrestrial cell sites. When you speak into a satellite phone , thesignal has to travel from you to the satellite, from the satelliteto the other person, and all the way back from the other person tothe satellite and then satellite to you. What is the round trippropagation delay when you use a satellite phone for communication?You may assume that the satellite orbits at a height of 21,000miles from the surface of the earth. This is the size of the orbitused by geosynchronous satellites whose orbital period is 24 hours,this means that the satellite is always over the same point on theplanet. Because of this delay many satellite phone systems usegroups of satellites with lower orbits and hand off the callsbetween them. Satellite TV systems do use geosynchronous satellitesso that you can just point your dish at one point in the sky. Delayis less of a problem for one way communications such as video orother broadcasts. Careful: you need to convert to a consistent setof units to use in your calculation.
