The safety chains on my trailer are a little too short. Is there anything wrong with taking another small section of chain and threading it through the tabs (where the safety chains normally connect) on the TV receiver and connect the safety chains to each end?

It depends on your local laws. A safer bet would be to get 2 of those links with the threaded lock on them and extend both sides of your chain. That way if one chain breaks, the other can still act as a back up. The way you describe, if one link goes, you have nothing.

I've got the same problem depending on which car I tow with. The full size van is fine - but the chains come up short with the minivan. Anyway - I took care of it in the way Roy describes. I leave them locked onto the chains so I don't lose them. That way they're always handy when and where I need them. Worked fine.

If the chains were too short for my primary tv, I'd get new chains. Good ones. These are the "last resort" (along with the breakaway), and my dad and I experienced the importance many years ago (won't say how many, but a long time ago) with a utility trailer.