Joe,
I would use a dipole type antenna - you can mount it inside the Aliner and it should work pretty well. Here's one marketed for boats: . For other options, I just did an Amazon search for "dipole antenna for cars". This type of antenna is better suited for FM, but would work on AM too.
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I would avoid an "amplified" antenna. They can work, but tend to be a bit gimmicky. Hope this helps!
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Another Old Dinosaur (Connor)
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