RTFM. Or take it back, might be broken.

can i suggest, a builders quality, solid wood, five pound hammer? place the box on the table, now slowly but gently, raise the hammer and progressivly tap the box along its seams, checking for breakages as you go, once done, smack the box with the hammer for a more effective result.

Regards

Annie Wood

when your on the screen for tuning it should have a bar that says signal quality or signal strength if thats below about 80% you wont pick up the channel and need a better antenna.