My 1998 4runner stereo had two antenna leads, what is the small one for?

I recently removed the OEM stereo out of my 4runner for an aftermarket stereo. The original stereo had 2 antenna leads plugged in, a regular one and a smaller antenna lead. where does that lead go? or what does that lead do? I am not getting all my stations so i hope this is the problem, not the stereo or the antenna itself.
It's a power antenna.