Apocalypse power
Right. Another possibility is to use the charge on the UPS on your computer as a source of 110 AC for your radio's DC converter. Not very elegant, but it would work. The car already has an am/fm radio for typical emergencies.
Still, I shudder to think of the circumstances where you would burn your car's irreplaceable gas just to be able to power up your short wave set.
How are things on the road?