Fishy ...
The history of the wee hours of Pearl Harbor and Dec. 7th talks about the new gadget the military had ... a radar unit.
So 1941 would seem to be the earliest that radar existed.
And that first Pear Radar could see a target at 1000 AGL only from about 20 miles. Up on the peak, it could find a plane at 25,000 from 150 miles.
So nothing at all in a class that could have been anything. And it was brand new in 41.
Chain Home predates 1941.