About: http://webisa.webdatacommons.org/137172371

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	In fact the basis air navigation beacon system still in use to today is a low frequency AM band transmitter that has changed not one iota since the 1930???s (Apart from transistors replacing valves).
http://www.w3.org/ns/prov#wasQuotedFrom	johnquiggin.com