Model rocket manufacturer Estes Industries sold a radio-based locating device called Transroc that fit inside the main body of a model rocket or model airplane. I'm interested in radio-based locating devices, including the TRANSROC and associated accessories. If you have one of these devices gathering dust in your attic or basement, send me an e-mail! More information about the TRANSROC TX-1 transmitter and associated accessories, along with scanned manuals, is available at transroc.org