It's amazing how far we have come in 80 years .....
Before the application of radar became a reality a number of 
experimental early warning systems were developed by the British 
military.  One which showed the most promise – as it actually worked – 
were the acoustic mirrors built at Denge on the south coast of England. 
 Quickly superseded by radar they were abandoned but still remain at 
their post, obsolete concrete leviathans on an island in the middle of a
 nature reserve, reminders of a dangerous time in European history.
LINK HERE 


Yeah, I've read about those.
ReplyDeletePretty neat thinking, and they were quite effective.