Radio Question - Break in the line?

When I bought my truck there was an aftermarket antenna box behind the passenger side visor. I asked seller (who had the truck less than a year) and he told me there was a break in the factory antenna line and that's why the antenna box was there. He installed an aftermarket Pioneer radio, so I assume he put the antenna box in at that time. The truck as a 8" aftermarket antenna mast on the factory antenna base.

Anyway, reception has always been terrible, and I have been doing some other work on the truck, waiting on parts to arrive, so I went ahead and pulled the radio out to see what's going on. I don't see a break in the factory line. I traced it all the way back to the factory antenna base and it seems to be intact. I also plugged in the antenna just to see what it does, and I got reception. A few stations come in just fine, but it doesn't pick up a lot of stations. I've also noticed that there isn't any change in reception if I remove the aftermarket antenna mast from the base, reception seems to be the same. If I unplug the factory antenna wire from the back of the radio then I obviously don't pick up any stations.

It seems that the factory antenna assembly is at least partially functional. Could it be that I don't have a break in the line and I just have a crappy aftermarket antenna mast? Or does it sound like my factory antenna assembly needs to be replaced? I listen to the radio all the time in my truck, so I want it to work.

 

I also noticed the aftermarket antenna had a torn tire, and there was a "antenna amplifier" installed. For some unknown reason the factory line had aluminum foil wrapped around it (I removed the aluminum).

 

Update, I confirmed there is a break in the line using a multimeter. I have infinite resistance on the center lead, so I'll be swapping out my factory antenna base.