Transit 5B-5 is a US Navy navigation satellite that was an early version of the GPS/GNSS system we enjoy today. It was launched in 1964 and has been transmitting continuously for roughly 60 years. Unlike many dead satellites that only emit a carrier tone, this one still broadcasts modulated telemetry on about 136.65 MHz, making it a fascinating target for amateur radio and SDR hobbyists. Over on YouTube dereksgc has uploaded a video that is a deep dive into the Transit satellites, and tries to unravel the convoluted naming scheme. In the video, dereksgc digs into historical documents and compares

Transit 5B-5 is a US Navy navigation satellite that was an early version of the GPS/GNSS system we enjoy today. It was launched in 1964 and has been transmitting continuously for roughly 60 years. Unlike many dead satellites that only emit a carrier tone, this one still broadcasts modulated telemetry on about 136.65 MHz, making it a fascinating target for amateur radio and SDR hobbyists.