Marconi Peta Meter (Constituent Parts)
Constituent parts forming the Marconi Peta Meter, thought to have been photographed at Weyhill in early 1970. The rectangular box at the rear was the radar unit that would have been placed at an angle to the roadside in order to get the correct reading and radar beam direction. It was powered from external portable lead-acid batteries. The inter-connection cables provided connectivity between the radar unit and the meter unit via the power supply unit.
"In the picture you can see an arrow (red) painted on the top of the unit which had to be parallel with the traffic flow. Not a very exact science I do believe :) Often Norman Butler CWT at Harrow was asked to be an expert witness in a court hearing when motorists doubted the accuracy of the readings of the PETA unit."
Many thanks to Alan Copperwaite for providing supporting text enclosed by "" to this photo caption and for a minor correction to the original text.