Radarplex
Technical details

General Description

Radarplex may be sub-divided into the following individual systems:

• Command System: this section handles the antenna position control servo functions and various on-off relay switching commands
• Tellback System: return relay functions plus digital read-out data from the antenna azimuth and elevation encoders;
• Video System: radar video, combined trigger plus sine/cosine turning data for the PPI and RHI displays;
• Miscellaneous: alarm, test and status monitoring functions, plus provision for additional telemetry facilities depending on installation requirements.

Apart from the specialised interfacing arrangements involved, the Command and Tellback systems were functionally identical with the Bureau-developed "Teleplex" equipment used at a number of locations for meteorological telemetry. They were approved for connection to private telephone lines under Telecom permits.
Spare capacity in the Command and Tellback links was used in such "house -keeping" applications as fire alarm indications and control and monitoring of emergency power generation equipment.

An overall block diagram of the Radarplex Remoting System

WF44 Modifications
Three significant modification was all that was required to a standard WF44 radar system to allow remote operation by Radarplex:
The WF44 Transmitter trigger unit was modified slightly to allow its internal repetition-rate generator to be externally synchronised, -when in weather watch, to a 250 Hz signal derived from the Radarplex Video Transmitter.
The radarplex system energised the azimuth and elevation antenna resolvers with its own internally generated reference waveform from which DC sine and cosine signals are derived for the PPI and RHI units.
The Remote Control Console was programmed for Radarplex use by fitting an appropriate link plug on its rear panel.

Construction
Wire-wraping the card frames for the system was contracted to two companies. One was Zephur Products, in Mt Waverley a suburb of Melbourne and the other was in Sydney.(2) The story is told that this Sydney company employed illegal Spanish migrants!

References
(1) EH355 RADARPLEX Technical Handbook
(2) Chris Heal (private communication 2002)