1. 
   Ionosonde
   An ionosonde, or chirpsounder, is a special radar for the examination of the ionosphere. An ionosonde consists of: The transmitter sweeps all or part of the HF frequency range, transmitting short pulses. These pulses are reflected at various layers of the ionosphere, at heights of 100–400 km, and...
   Found op http://en.wikipedia.org/wiki/Ionosonde
   
   
2. 
   ionosonde
   radio equipment designed to carry out ionospheric soundings and to record the results
   Found op http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=705-07-70
   
   

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