Page 9 - Royal Observer Corps

The webmasters would like to thank Bob McIntosh, a former R.O.C. Observer who
was stationed at No.7 Group. Bedford.

The following Photographs were taken at Oxford 10 Post. They were all taken just
after standown of the main body of the Corps. The black and white photographs are
of the WW2 Centre Opps building used as the Group Headquarters admin and
Group training block up to stand down.

This photograph shows Bob sat below the Bomb Power Indicator inside the Bunker.
Above ground a pair of circular plated baffles would be affected by the passing of the
blast wave. The detector was connected by a steel pipe to the indicator dial below
ground in the protected monitoring post. The dial was wall mounted and measured
readings from 0.1 to 5 pounds per square inch peak overpressure. Readings below
0.3 pounds per square inch were noted but not reported.
The baffles were normally stored below ground and only screwed onto the top of the
pipe at the start of exercises or at Transition To War. Outside of operations the BPI
pipe was protected by a screw on cap and there was a drain valve at the base of the
instrument to remove any excess rainwater.

If the BPI registered a reading of 0.3 or higher the operator would wait ten seconds
before pressing the reset button and making a report to the group control. One
minute after a BPI reading an observer is sent above ground to change the
photographic papers in the Ground Zero Indicator.

Photo credit: Bob McIntosh