My Hd omnidirectional antenna will not pick up any channels. My friend has the same TV (Panasonic Viera, Plasma) He hooked it up on his and it worked!!
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How well an antenna will do is totally location based. If the antenna works at another location, it is not a hardware issue. You may need a more powerful antenna, or a higher location. The website I suggested can help you work through the issues, and show you where your signal is coming from.