Assertion: lightning detector | /r/CapableOf | detect low frequency radiation
Facets:
value: in the past
type: TEMPORAL
Source sentences:
text: In the past, lightning detectors, both inexpensive portable ones for use on the ground and expensive aircraft systems, detected low frequency radiation because at low frequencies the signals generated by cloud-to-ground (CG) lightning are stronger (have higher amplitude) and thus are easier to detect.