Assertion: antenna | /r/MadeOf | dozens of turns of wire
Facets:
value: in am radios
type: LOCATION
Source sentences:
text: In AM radios built prior to the discovery of ferrite in the mid-20th century, the antenna might consist of dozens of turns of wire mounted on the back wall of the radio – a planar helical antenna – or a separate, rotatable, furniture-sized rack looped with wire – a frame antenna.