Here's a good question, and one I commonly receive:
How can I hook up my miniature tvs to dtv? All they have is antennas -- there is no cable port.
If you don't have a place for an external antenna hook-up, you're out of luck after February 17th. I understand there are some companies producing portable TV's with a "Digital" tuner, but I'm sure they cost a pretty penny. Otherwise, you have to have a converter hooked up to receive the new signal.