You're leaving out a heck of a lot of history & other details regarding the site, but that's your prerogative. I will say that the site is listed in the RRDB & is fairly well-known, so if your visit was recent, more info & photos regarding the condition of the overall site would be nice -- when I was last there, there was a friendly caretaker...
As for the site on your left a few miles before you hit the main site, that was once the main site's primary radio annex. When I was poking around it, I had the added bonus of the lonely, horny woman who lived directly across the street notice me in the compound, and instead of calling po-po, she invited me over to her house for a glass of ice-water...
It's entirely possible that someone has bought that compound (I'd tell you what that sort of compound was known as, but doing-so would give-away info about the site that you seem to want to keep secret) & is re-using it, but if-not, no real-reason for the few neighbors to get protective over it unless you're carrying a a gas can, spray-paint, or keg of beer -- it's pretty trashed.
By the way, I learned the hard-way that the microwave antenna & omnidirectional antennas atop that tower you photographed (which was atop another structure of interest...) were used by the local sheriff's dept.
It was NOT fun to be sneaking & peaking in the more historic building nearby, and suddenly hear law enforcement radio comms coming from outside! Turns out the tech who was last at the Sheriff's Office repeater site left the volume up kind of loud on the repeater inside the building.
P.S. Be careful poking around that specific site & region -- lots of druggies protecting their grow sites hidden in the forests, but maybe things have changed now that Cali has legalized marijuana.