One thing, pre visitor's center, that was known by a small number of people, is the spacing of the antenna pods on the 3 legs of the array were arranged logarithmically. The spacing got increasingly closer at the center of the array. The spacing had to do with the frequencies that were being received. When we lived nearby a 162 MHz frequency was assigned to them. I only had a BC-210 with 10 channels at the time and could not give up scanning what I had in there to listen to it much. Occasionally, I got a weak signal that would overwhelm the front end of the 210, with a repeating set of tones that sounded somewhat musical. I knew that the 210 had an I.F. of about 10.1 MHz so I took my trusty FRG-7700 receiver and tuned that frequency in. Sure enough, the signal was stronger when I dialed in that frequency or thereabouts. It was eerie as I had just watched the movie "Close Encounters of the Third Kind" a few weeks prior to moving there. I knew nothing of the facility when we drove east on U.S. 60 through Datil. These dishes appeared and an image of a very tall man with his arms pointing to the sky came to mind as I struggled to figure out what the heck they were. It was just before sunset and that added to the effect.
The diameter of the dishes is 82 feet and each structure weighs 230 tons. I can't find data on how high above the ground they stand, but appear to be up to twice the diameter of the dish. There are a total of 28 of them, 27 out on the array (9 per leg) and one spare. There is a building that would have to be a minimum of 8-10 stories where the "spare" is located. I think the spare is actually the one that is pulled into the shop for maintenance and refurbishing. The "locomotive" that moves them is lifting 230 tons and moves slower than the rocket movers at the Kennedy Space Center. On the side of the locomotive, when I lived nearby, is painted "Hein's Trein." It seem to remember it was named after the engineer in charge of the design and construction of it, which, you guessed it, was built in Germany. Signals as high as 50 GHZ are received. Wow, the wavelength at that frequency would be darn short.