[Milsurplus] Oddball antenna spotted, again.

[KD7JYK DM09]

I can usually figure things out pretty quick, but I spotted an oddball 
mobile antenna, which I had seen once before, but forgot about, and I 
still have no idea what it is...

I came out of a bank in Dayton, Nevada a few days ago, and there was a 
somewhat typical looking Dodge diesel truck idling in a parking spot 
near the door.  It was black/gray, with a fiberglass camper. It wasn't 
bright, shiny, and new, it looked like any other truck you may see.  It 
had tinted windows, and I couldn't see who was sitting inside through 
the windshield, due to glare and reflections.

What caught my eye, was a roof-rack, typical of a ski rack, just a 
square rounded tubular rack, like a flimsy luggage rack.  Inside the 
rails of this rack was a thin, round fiberglass radome, about two inches 
thick and about two feet across.  It was mostly obscured by the rack, 
unless you looked from the top.  It sat up slightly from the roof, like 
the rack, and was also black, and gray.  It looked exactly like a very 
small AWACS antenna, but didn't rotate, it was supported by a few 
stand-offs.  I HAVE seen one other over the years, on a similar truck.  
I didn't notice the plates, it may not have even had one on the front, 
nothing else seemed out of the ordinary.

Any ideas what I spotted?

Kurt