“There are some threads you don’t want to unravel.” Widower James (Harry Shum, Jr.) is an observant man. A video archivist by trade in the late 90s, James spends his days logging old broadcast tapes for posterity, and his nights dreaming of his wife who disappeared years ago (11/22/96, according to a tattoo on his inner wrist). After discovering a bizarre tape with a Max Headroom-like “broadcast signal intrusion,” James embarks on an odyssey into a strange unsolved mystery that might be connected to his wife’s disappearance. “Broadcast Signal Intrusion” is another exercise in high tension from Jacob Gentry, whose 2007 film “The Signal” plays in a similar sandbox of sinister transmissions.