Et Phone Home is an abandoned radio telescope inferometer that was created in the 1950s.
Consisting of nearly 50 parabolas they were made to observe the changes in solar activity.
I am not sure how long it has been out of use, but I do believe it is being maintained by enthusiasts and some of the site is still functional.
I visited here twice on the weekend trip. Once in the middle of the night on my own then on a different day I returned with company. I did not expect to hear loud music around here at 2am which was a bit of a shock! Sadly it was rather misty on the return trip so catching the colours of the sunrise was out of the question.
The next month I got to visit Mullard Radio Astronomy Observatory in the UK which is another radio telescope site.