Though I don't get to the Southside of Hampton Roads all that often; when I do, trying to figure out who I am hearing between NOB, NNSY, Oceana, Little Creek, and Fort Story, is a nightmare. Then throwing in Yorktown just adds to the confusion.
Even with the RR displayed control channels entered for a specific base, I still get TGs from other local bases.
On my Unication G5 recently, I had the NOB CC locked on my NWSY system and was hearing the Norfolk talk groups. I live about 6 miles from NWSY and a good 20 from NOB.
It could be it is because they are all on the same DOD network (United States Department of Defense (14C)), with just RFSS and site numbers different. Also, some of the Midatlantic TGs seem to be used across the various bases.