Sentence:  In the relatively short time since these early observations , Venus has been observed at additional wave lengths in the range from 0.8 to 10.2 cm , and Jupiter has been observed over the <WSD>wave-length</WSD> range from 3.03 to 68 cm . 
Meaning of the word marked with <WSD> tags:  the distance (measured in the direction of propagation) between two points in the same phase in consecutive cycles of a wave