In the mid 1970's, when I first got out of high school, I spent some time in Boulder. My favorite weekend thing to do was to ride my Yamaha DT360 in the mountains between Boulder and Nederland, taking any dirt road I could find along 119. On one of these adventures, I encountered a wide spot in the canyon, along a paved road, dunno which road, but the dominant feature was a flat grassy maintained area, approximately half the size of a football field, surrounded by a tall "keep out" fence. Suspended approximately 10ft above the grassy area was a system of wires, on a roughly 10ft by 10ft grid. There was a small red brick municipal looking building at one end of the field. I don't recall any parking area for vehicles, and I don't recall any signage, although there may well have been some. It didn't resemble any power substation I've ever seen. I encountered this place more than once while on my weekend rides. One time I decided to stop and take a breather right outside the fence. I was very surprised to hear a low, short, but distinct hum coming from the suspended wires (presumably). The hum would last a couple seconds, then stop, and repeat every 15 seconds or so. Over the years I've always wondered what that place was. I would wonder if it was for oil exploration, but it was a permanent facility. I would think that oil exploration equipment would be mobile. Someone suggested it was a ultra low frequency facility for communicating with US submarines. I'd read that such places existed in the Rocky Mountains. I don't think it was a secret military facility because the road went right past, within yards if not feet, with not a guard in sight. I've tried to find it on Mapquest, but no luck. I simply don't recall how far I would range along 119. Can any locals in the area advise if this place still exists and what the heck it was/is?