I would always have a bag full of alligator clips wires on me just for cases like this. Just clip a few of these together and clip into the ANT jack - Works wonders sometimes...
You could never go wrong building up one of the twin leads antnna for AM/FM reception like discussed above... Just tape the antenna to side of the trailer or hang between something. Even just throwing it out of a window would probably work like gang busters...

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The B version would be best to use for FM Radio reception...
Roy Ken