I know it's not really a big deal but:
Has anyone noticed there antenna coming loose?

About once every 6 months have to re-tighten it.

Nope...I just replaced my antenna with a low-pro and that is the first time it's been touched since the first time I tightened it in November 2002 when I bought the truck.

I knew the history of these antennas, so one of the first things I did when I bought the truck was take a wrench to the antennna. 2 1/2 years later it was still as tight as I left it.

Good idea to check the tightness periodically. They can loosten up.

there was a tool in my glove box for the antenna. maybe the knew the thing was going to come loose often.

Mine kepy coming lose. I got tired of tightening it every few weeks. A couple dabs of blue loctite, (Not too much) its been snug ever since. (1+ year or so)