USAF 19th TASS (CEM) on the ground???

[Docthrush]

The actual question is towards the bottom if you dont want to read me bable!
My grandmother has been Ill for some time now recently she had to move to the area so that family could take care of her. She past away this past wed. One of the things that we did as a family was slowly get rid of stuff at her old place before she moved down here. And we found my Grandfathers foot locker. My grandfather has been a larger than life image to me all my life. I never got to meet him but know that he did some what we would call today "high speed low drag" stuff. He was involved in communications that is about the most anyone can tell me. We know that aside from serving in vietnam he was in some odd places especially for the USAF. We know at one point that he was on an oil rig off the coast somwhere. Why he was there? who knows.
Anyhow....
My question is this. The pictures that he has are all on the ground with what appear to be army infantry. In his foot locker were a set of ERDL uniforms. Now, I will admit that I kinda hope that he did some cool stuff while in vietnam but just that fact that he was a lifer in that time is impressive to me. That he volunteered to go while he had a wife and daughter at home is even more so impressive.
Does anyone have any knowledge of what the 19th tactical air support sqdn did? I know that they had FAC aircraft and some commo guys. Any idea why he was in the field instead of an airbase? Why the cammo and not the norm od uniform?
Any help would be great!!!!!!!

EDIT: I found some more info that says he was with the 19th TASS CEM, This was also found on a reciept from the base PX..