UFO Sighting in Windsor, Illinois on July 31st 1977 – Bright light with flashing lights moving, landing and rising then moving again

My best friend and I had gone to a night trail ride at the riding stable we were working at for the summer. The ride was broken into 2 segments with a break for chili and drinks in the middle. I was 16 at the time and did not like the taste of beer, tho my best friend loved it, so when the group was done eating but several wanted to have a couple of beers before going back out, a younger girl and I decided to ride the first part of the trail ahead of the group and wait for the others at the top of the ridge since neither of us wanted to drink. We sat on our horses looking out over the valley and chatting when we noticed a light with blinking lights to our NE moving slowly from SE to NW. At first we were not concerned as there was a Guard post that often flew helicopters in the region and we assumed that was what it was. It would travel a short distance, 100 yards or so, descend, be at ground level for about 20 seconds, rise back up to about 100', then repeat the process. Our horses were also watching the light closely, which was why we paid attention to it...heads up, ears & eyes locked on it, snorting a bit. It took several minutes before we noticed that it did not sound like a normal helicopter, there was only a loud hum not the chopping sound one would normally associate with a helicopter. At that point we began to not only watch it closely but comment on it and ask each other questions about it, like "what the heck IS that" and "what do you think it's doing". I finally noticed that it seemed to be following the exact path of the high tension wires that cross the valley, just a few seconds before it went down again almost due north of our position. About 5 seconds after that descent the lights all across the valley went out, quite noticeable as the local saw mill worked 24/7 and always lit up the horizon so when their lights went out it was immediately obvious. The object rose up one more time, and now the horses were both trembling and very tense, snorting loudly and shifting about. The lights began to blink more rapidly, and the hum became almost a whine and rose in pitch an instant before the thing shot straight up and out of sight, gone in a matter of moments. That was it for the horses, they both bolted for home and we had our hands full just staying with them for the panicked gallop back to the barn. We told the others what we had seen to open scoffs and ridicule, so we did not talk about it except to each other the rest of that evening. Perhaps 10 minutes after the object vanished and we had started back out for the last half of the ride, 4 helicopters flew over the area, criss-crossing the entire valley, flying for the better part of an hour. My best friend and I had planned on camping at the stable since it would be 2am or later when the ride would be over and the horses all put up, and the next morning she listened to the events of the night before with less scepticism, and agreed to ride to the top of the high pasture where the power line towers crossed the property of the stable. When we reached the one closest to the fence line, the base of which was about 20' on the other side of the fence in a wheat field, we could clearly see from horseback that the wheat was flattened down in a circle, swirled in a perfect spiral just like what we would later hear about as crop circles, with three deep square indentations in a perfect triangle just inside the outer edge of the circle. At that point my friend became quite frightened and to this day has refused to discuss anything that she saw. Being 16 at the time and having been ridiculed on the night of the event, it was many years before I was willing to discuss this with anyone. I realize now that had I spoken up there might have been physical evidence retrieved from the site.