Log Category of Documents:
Circular #35/VP and #10/tt, dated 23 Feb 66, signed by ag Tan, Chief Admin Staff, of guney 100 aka Ninh Thuan Prov Party Committee, distributed to all units, states that during the past, transistorized sound detectors were dropped over certain VC base areas by Allied aircraft. This signal apparatus, made of celluloid and possessing an antenna with a separate battery was capable of recording noise within a 300-meter radius and transmitting it to aircraft.