Here Synuefai IC-S d5-35 I collected black box from signal ... I think it is really weird since no humans around, and it is close to "mass center" if it was "solid methal triangle" described by stars I mentioned before.
Actually couple stars around has "degraded emissiions". Like somewhere near must be human's base.
I visited again those systems (about 20hrs later) and no signals there any more. But I have names in log - where I took cargo, so just put names here, in case it leads anywhere.
Upd: just got spawn in synuefai ic-s d5-34 while was FSSing. EDDB shows closest human's station 154ly. Not sure if it's close enough to cause spawns in d5-xx systems.
Damn, visited that starport ... "i'm first to discover 10 bodies" I was flying on already mapped systems long ago! That show quality of data related to raxxla. It's incomplete.
USSs spawn out beyond 500 LY, maybe as much as 1 kLY.