I explained to the Radio Shackologist what my project was, and after re-explaining it (by opening a box of coaxial cable and pantomiming the process of cutting), he sent me home with the connectors I needed. Or so I thought.
When I got home and got ready to cut, I did something odd. I read the directions on the back of the packaging for the connectors.
"Do not use on cable TV."
Well, I was fairly annoyed as I had explicitly explained that I was using this for splitting my cable TV connection. Back to Radio Shack I went.
I met with a different Shackologist this time. When I explained my situation, he said that these connectors are the right ones. Here's a paraphrase of out dialogue:
RS: These connectors should work.
Me: Then why would the packaging clearly state NOT to use these for cable TV?
RS: Maybe it would void some service agreement with the cable TV company.
Me: Um, well, the packaging then goes on to say, "For cable TV... use crimp-on or solder-type connectors, also available at Radio Shack."
RS: Yeah, the ones you have just sort of screw on the ends of the cable, for the others, you have to use tools.
Me: I have tools. Why are the other ones recommended?
RS: Well, maybe those give a more powerful connection.
Me: Oh, well I wouldn't want that. Especially not for the additional .79 cents...
I don't know if he appreciated my sarcasm. And, besides, I'd probably be willing to pay almost any reasonable additional cost if something was going to give me more power.
In the end, I got the correct connectors, I cut my cable, I used my pliers to crimp the connectors, and HD TV is working!