Geograph - photograph every grid square

Please see Jeff's SP6455 : Birth of Radar Memorial for a close up of the memorial stone and its inscription plate taken in 2002, when it was probably new and unweathered. Dipole aerials set up in the field beyond were used to test the theory that energy from radio signals could be deflected from an aircraft's body. So why this particular field? Well, the location had to be close to the Daventry short-wave radio transmitter, but also had to be shielded from it by hills as otherwise the signal would be too strong.

On 26 February 1935 an RAF Handley Page bomber aircraft was flown over the site and the theory was proved. This image was taken 80 years and 2 days after the successful test.