Transit 5A via Wikipedia
Many thanks to SWLing Post contributor, Dan Robinson, who shares the following article, which explores the story of Transit 5B-5 — a U.S. Navy satellite launched in 1964 that remains in orbit, continues transmitting telemetry signals, and is still monitored by amateur radio operators around the world more than six decades later. Fueled by a long-lived radioisotope power source and tracked by the SDR and ham radio community, this “zombie satellite” stands as a fascinating reminder of Cold War-era engineering built to endure.
There’s LES-1 as well. It went up in 1965 and it’s still there. No more telemetry after the batteries failed, but the small beacon transmitter on 237.0 MHz is still working and can be heard whenever the satellite is in sunlight. It’s a pretty weak signal but it’s easy to recognise from the doppler shift. It can be tracked here
https://www.n2yo.com/satellite/?s=1002
In the late 70’s it took me a good week camped out with a Marquardt receiver, batteries, and a small gasoline generator to get a useful fix for tying surveys.
You might want to confirm how 5B-5 is powered.
have fun