Several weeks ago I noticed that 170.8000/171.3500/173.1875 carry the same traffic simultaneously. 170.8000 is P25 NAC 098, 171.3500 is P25 NAC 090 and 173.1875 is P25 NAC 099. Traffic is mostly from radio ids 848xxxx with some from radio ids 52xxxxx. All encrypted except for what appeared to be accidental clear transmissions such as "10-8 Manassas" etc. 173.1875 is carried in the db as being part of site 007-001 of IWN NCR Integrated Wireless Network (IWN) National Capital Region Trunking System, Washington, Multi-State - Scanner Frequencies but I get a good decode of NAC 099 instead of NAC 010 and 011 that is normally associated with IWN.