Now that I've seen this I remember the light stick in the water bottle attached to the antenna bit. I just don't remember what it was for.....
Mainly, the antenna chem sticks were for IR vehicle identification (including from the air) without interfering too much with NV equipment. Using multiple bottles vertically allowed different colour codes to be displayed.
A side benefit was that, within columns and convoys, the movement of each vehicle could be tracked by others under poor light conditions.