This should about the same as you have on the 2005 model
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Usually antenna bases come with cable permanently attached so yes you would replace cable and base at the same time.
You can splice antenna cable using the correct ends and coupler
Google: "Coax Cable splicing"
Simply twisting the wires together doesn't work well with coax cables, a coax cable is a "wave guide", the radio signal travels on the outside edge of the center wire, and the white plastic surrounding the center wire holds the ground, mesh wires, at a specific distance from the center wire to prevent signal loss and blocks other frequencies from entering.