In some of the exterior saucer scenes they are also dummy boxes. The hero versions had a dark colored box behind the radio, with a wire leading into the radio to power the lights. In some scenes there was a duplicate of the radio in front of the holster, which also had the battery box, but no mic/camera. This prop may have been built for one of the deleted scenes that got cut for budgetary reasons.
I just found it funny, when I discovered while looking at some stills from the movie, that they used those plastic jewelry boxes for the radios, and the other device by the holster. I don't know if you can still get them, but cheap, and inexpensive jewelry use to come in plastic boxes. The base was usually black, or dark blue, and they had a clear lid. The clasp was just two plastic beads molded in to each half. The hinges were two beads at each corner, which had a piece that snapped into them from the other half of the box.
Useless fact, that large device with the clear dish had working lights. I don't know if it was built for FP, or some other production. But in "The Man From U.N.C.L.E." episodes, "The Brain Killer Affair", and "The Cherry Blossom Affair", they use it, and the white tubes were lite up. That other radar unit, with the yellow stripe on the dish that got carried in was also used in the opening credits for a show, I think it was "Science Fiction Theatre". The reason for the yellow stripe, was to show the dish spinning.
David.
