54118 Radio id 9920 Over 300 hits in one day.
51708 Radio id 9003
Not sure who these are.
I'd say 51708 is going to be an OSP talkgroup. Yeah, I know, everyone talks about the 515xx talkgroups, and they are right. But I know of many OSP talkgroups between 51502 and 51795. So I personally would consider anything in that range as OSP related.
Heck, it might even be that OSP is online up in your area playing around, one of the posts nearby whatever towers you were monitoring.
To add some more confirmation to that, thus far I've seen a ton of 9001xxx through 9004xxx radio IDs on various OSP talkgroups.
Somebody up in your area should start listening to the comms and see what's being said. Or perhaps it's an encrypted TAC talkgroup of one of the posts.
The 9920xxx radio IDs that I've seen have communicated on TG 54218. Not sure what state agency that is, but might be the same state agency that is using 54118.
Mike