Zeppelin raids are detectable again.
 

Thanks to our recently repaired defences. See here.
Sunderland's WW1 acoustic mirror restored - BBC News

There are three other surviving WW1 sound mirrors in the North East of England as well as the more well known ones in Kent . More details on all of them in this very interesting website ;
News and updates | Sound Mirrors | Acoustic early warning systems, spectacular remnants of a dead-end technology on the British coast

Great article and story...but I take issue with then"dead end" line. If it hadn't been for the system of fighter control based on acoustic sensors, radar would have been just an interesting scientific what-if in the story of us losing the Battle of Britain.

In much the same way as the Gloster Meteor is credited with saving us all from the V-1 scourge radar gets all the glory for the Battle of Britain. The fact that it was one aspect of the world's first integrated air defence network is always forgotten, as is the fact that once the raiders had crossed the coast there was no radar at that time. Step forward the Observer Corps, but many books on 1940 barely mentions the organisation, and never acoustic mirrors.

I seem to recall that there is some kind of acoustic sensor from WW2 still standing on Malta as well.

Putin trembles in his shoes.

Here:
Flash Earth - Zoom into satellite and aerial imagery

Martin the Martian,

As for Malta, probably some at Ggantija (to give early warning of approaching pterodactyls !) :sad:

D.

That's the one!

Thanks chaps.:ok: