google-fu, don't fail me now
it turns out that dad was in both 173rd airborne AND 82nd airborne in vietnam. this gives me some more choices in the ink design. but the signal battalion that he was in was deactivated in the early 00s, much like mine was when they called themselves going to a more "mobile" force. those units were intergrated from slice elements for their brigades and made into new units. i like the 173rd stuff better, so it looks like that's what i'm going with, but finding info about something that isn't necessarily archived is truly like finding a needle in a digital haystack.