National Aeronautics and Space Administration

Glenn Research Center


Why is Propagation Important?
Knowledge of atmospheric propagation characteristics at a particular site provides critical information which aids in the system planning for ground-to-space communications system design and performance.

What Are We Measuring?
As spectrum use progresses towards the Ka-band frequencies (26 GHz and above), increased losses due to rain attenuation and atmospheric noise temperature can degrade ground-to-space communications link margins and cause loss of signal acquisition and data return.

How Do We Measure Propagation Effects?
To measure the degree to which RF signal propagation through earth’s atmosphere affects the availability of communications links, several tools are at the engineer’s disposal.