Digital Television Transition and Public Safety...

Question

I have just learned of the new law to end analog broadcasting.....
I have an LG 26LC2D LCD TV....according to the adds when we bought it, it has the "ATSC/NTSC/QAM Clear Tuners" but I can figure out how to get the signal. The Menu option to check the signal is greyed out and I can't select it. The only thing I can find in the owners manual is "Digital Signals: Only when the input signal is DTV or CADTV , this function is available." I'm not really electronics savy so I'm not sure what that means? Any help???