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Most dealer show rooms use in-store signals that are designed to optimize the capabilities of the displays. This usually means they will use a high definition signal.
If you are viewing your TV set with a standard analog signal, you will not see your set's full display capabilities. You'll need to contact your cable or satellite service provider about options for obtaining a high definition video signal. To obtain off-the-air high definition broadcasts, an aerial antenna is required. Check with your dealer or electronic supply store to select an appropriate antenna.