It looks interesting. Try a search using AS-1182/URC-40 instead of AR-1182...
It looks around 1.5 meters long and those elements will probably have that antenna down to 138 MHz and up to 400 MHz, as you noted. I would venture there to be some reasonable gain, as well as directivity, with those elements.
The connector may be HN, so you might need an adapter. Sweep it with an analyzer and many questions will be answered. I also suspect that antenna probably had a soft case of some kind, military and all.
Ping me if this is for sale. I would like to play with it.
Also, prcguy will probably know more about it, as well as have one or two of them tucked away.