John,
Well, it's just a plain coax cable that I got with my router, so I just went to Radio Shack and bought some $4 F-adapters and screwed them in.
But that's a thought, maybe I'll try out a more specialized audio coax cable:
How about this one?
The picture shows a strange end, not sure if this is the right one.
or this one?
This looks a little more like it.