Maybe there's something unique about how these low-quality radio transmissions sound that make these ineffective?
Are you doing any kind of speaker identification?
This is definitely a very hard problem to solve.
https://www.broadcastify.com/listen/feed/32890
(edit: also, thank you for keeping this service up and running for so long, have been a regular user since the early RR days. Would love to have a comment/live chat option if your backlog is getting bare :))
Repo is here if you need to report (or just fix :D) bugs in the webapp: https://github.com/lunixbochs/feeds