Aerial Base wire Help

Hi.

Ok i got a clio van 2002

Got poor signal. Trying to remove the aerial base and got as far as undoing the 22mm bolt to loosen the base and unplugged the short the power connector but the aerial coax wire itself seems to go for miles.

Does it go all the way to the head unit or is there a joiner somewhere.

I got as far as the rear window but can see anything. I have ply panels inside which will come off but would take some time.

Tried looking and most people say it comes right off bit mine seems to be soldered directly into the aerial base

Thanks