The rush was that I wanted to get back there today and hookup my AppleTV and the new coax. It is a freaking pain-in-the-ass to get back there and I won't trouble you with the details. I ordered the cable from Amazon on my phone while I was out shopping. Should have it tomorrow.
That's because no one would buy anything over six feet at the prices they'd charge for such a cable in a big box store.
Since you have a cable that is working in the meantime, and thus could tolerate a few days' shipping time, consider buying one of ideal length from Monoprice. Some are even made of RG6, and ten-footers are still under $5. Non-RG6 less than half that.
My question above about needing an antenna has been answered. I found an AM antenna in my box o' electronic junk and now RF works.
As to the difference between digital and non-digital coax, the digital ones have the phono style connectors for one. Not sure about other differences.