I think I may have been a bonehead. Someone please let me know if I have. The 650 I have is a single tuner card (although it has two connections) so you can use one or the other, but not both. I think the simplest thing to do is to unplug the cablwe connection and try to detect the antenna connection.
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"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood, who strives valiantly, who errs and comes up short again and again, because there is no effort without error or shortcoming, ...so that his place shall never be with those cold and timid souls who knew neither victory nor defeat."
President Theodore Roosevelt
Speech at the Sorbonne, Paris, April 23, 1910