The need for permanent echo suppression processing was made
clearly evident by the work Dale Sirmans of National Severe Storms Laboratory
(USA) did in building a VIP unit for the RC33
in 1971. The result was less than satisfactory, not because the VIP was inadequate
but that without PE clutter removal prior to the integration process it was
almost impossible to distinguish the rain form the PE's on the display. So Peter
Mahony and Alf West developed a Suppressor system in 1976.
The Bureau was granted was granted a patent for the PE Suppessor in 1977 as a result of their work.
Only one Permanent Echo Suppressor was ever built. It was installed on the Laverton WF44 and though the meteorologists came to rely on it it was never classed as operational equipment. It and its associated VIP was removed in the late 1980's once the Rapic Transmitter was fully operational.