You're getting confused, so just buy the antenna from the link below. Do not go back to ebay and order one from china to save a dollar, it takes forever for inexpensive purchases to get to the states.
Once you get it, there are two tabs, one goes to ground, and one goes to either 300 or 75, because typically they tied them together inside the amp.
You don't need anything fancier than this, especially if you haven't been using FM anyway.
https://www.ebay.com/itm/Parts-Expr...098720&hash=item1c9249f7d4:g:51kAAOSwOudZwJK3
Once you get it, there are two tabs, one goes to ground, and one goes to either 300 or 75, because typically they tied them together inside the amp.
You don't need anything fancier than this, especially if you haven't been using FM anyway.
https://www.ebay.com/itm/Parts-Expr...098720&hash=item1c9249f7d4:g:51kAAOSwOudZwJK3