GrahamH's photos with the keyword: analogue

A two page test report for the transmission links for a two-way radio system. The links joined the track-side base stations and the control centre. The system is no longer in use. This is used for checking the links shown here: www.ipernity.com/doc/grahamh/24117033 E&M signalling over copper pairs in Australia was done using the 4W (1 pair each direction for the audio signal) circuit, ie no additional conductors. This is done in a similar manner to that used in feeding DC power to a condenser/electret microphone in a public address or studio sound system. The direct current for the signalling flows one way equally on both wires of a pair with the earth being used as the return conductor.

A two page test report for the transmission links for a two-way radio system. The links joined the track-side base stations and the control centre. The system is no longer in use. This is used for checking the links shown here: www.ipernity.com/doc/grahamh/24117033

A test sheet used to record basic measurements on a 4 wire plus E & M circuit. For this project the functionality was mostly derived from either two pairs of copper wires or a 64K slot from a 2M PDH stream. The links connected train radio base station controllers with the central control for the railway route. See www.ipernity.com/doc/grahamh/24117033/in/group/873405

Old work. Colour coding for wire used at PMG / Telecom Australia sites to interconnect various controls and alarms which were part of analogue microwave radio links - 1960s to 1980s. IDF = intermediate distribution frame, a bank of terminals for cables from equipment which enable interconnections to made and varied as needed.