I came up with a small theory about these transmissions from the woods, that were never explained.I know we can say that the lodge spirits travel in the real world inside owls, and spy on people in the woods. The Log Lady knows this, which is why she was telling everyone to go inside her house, where the owls can't see/hear them. And we know a giant owl took Briggs away when he was about to fill Cooper in on the lodges, maybe because he would end up being Bob's new vessel or they just didn't want a man well-versed in the lodges to spread the word.
When Briggs returns back to our world, he's wearing a pilot's uniform. This leads me to believe that he used a plane inside the lodge during the test that enabled him to send out transmissions, calling Cooper for help and also letting him know that the "owls are not what they seem". Time in the lodges is different, so it would make sense that Briggs would receive the transmissions a while before he would go on to sending them, and he loses his memories inside the lodge, which would explain why he didn't let Cooper know about this.
Has anyone had similar thoughts? Please discuss.


