While there are quite a few places that probably carry TVI filters for TV's, I think Radio Shack would be my first stop. They typically have carried them, and may be the cheapest source. That's for the filters that go on the TV. The TVI filters that go on the radio are definitely different, and not as cheap. They are also called 'Low-pass' filters, which is a fairly good way to 'Google' them. Try 'High-pass' filter for the ones for the TV.
- 'Doc