Radarplex

Radarplex Head Site Rack

In the mid nineteen-seventies, Alf West and Noel Schrumm developed a system for remotely controlling WF44 radars in the weather-watch role which was called Radarplex. It used only a two-way voice bandwidth circuit and a one-way video bearer to link the radar head and the operations room.

Normal weather-watch displays were provided in the operations room, together with a Bureau-developed Remote Control Console . A Radarplex rack at each location acted, in effect, as an interface between the radar equipment and the communications circuits.

The video bearer was a Bureau-owned Collins 8GHz microwave link on the Laverton/Melbourne, Mt. Stuart/Townsville and Cape Range/Learmonth systems. The Mt. Kanigan/Brisbane system used a broadband bearer rented from the Telecommunications Commission. The voice-bandwidth circuit was normally a rented private telephone line but was carried on a subcarrier on the microwave link system installed on the Cape Range/Learmonth system.

There was no distance limitation over which the system could be used; the longest link used was between Brisbane and Mt Kanighan, (about 120 miles). though experimentally the control functions were tested once from Melbourne to Mt Kanighan!(2)

Five systems were installed;
Laverton/Melbourne Regional Office VIC. installed February 1976
Mt. Kanigan/Brisbane Regional Office QLD. installed August 1976
Mt. Stuart/Townsville QLD. installed November 1976
Cape Range/Learmonth W.A. installed August/September 1978
Brisbane Airport/Pinkenbar QLD. installed November 1987

The last system was installed using an optical-fibre link for the video circuit. Due to the probability of "back-hoe brown-outs" (as the locals called failures caused by someone cutting the fibre) a low power 10.5 GHz microwave link was installed as a backup circuit. This facility was used a number of times over the first three years!

Collins MW518 microwave link

The Collins microwave link used from Cape Range to Learmonth didn't have direct line of sight from end to end. For this reason a passive repeater, consisting of two dishes back to back on a short tower joined by a length of waveguide was sited on the edge of the escarpment to ensure a good signal path.

References
(1) EH355 RADARPLEX Technical Handbook
(2) A.L.West (private communication)