Length of millimetric wave guide used in an early Post Office (GPO) experiment, 1970-1976

Length of millimetric wave guide made by British Insulated Callender's Cables Ltd and used in an early Post Office (GPO) experiment on the composition and performance of repeater equipment in the millimetric waveguide field trial, 1970-1976.

Made of resin impregnated tape; aluminium gas and water vapour barrier; fibreglass/epoxy resin structural support; fine enamelled copper wire helix

From 1970 to 1976, one of the key areas of research at the time at Post Office Research Centre at Martlesham was millimetric-waveguide system experiments. These experiments stopped in 1976 when it had become clear that fibre optics had superseded wave guide technology and so the experiments were stopped. Although an ultimately failed technology, wave guides contributed to the development of high-bit rate digital techniques and solid-state devices that later found application in optical fibre and millimetric radio-relay systems. This wave guide length was later used by a local scout group for tent poles until it returned to BT.