TV coax cable adapter for iMac viewing

Dear all,

I hope you can help with this. I have recently got an iMAC and would like to view tv via the iMAC. My question is what type of unit/adapter would I need to connect the TV caoxial cable to the iMAC so as to enjoy TV on my iMAC.

Thank you
Caoimh

Here is the one I use:

Overview EyeTV Hybrid

There are others, but I really like this one.