I've had friends who have tried a few of the wireless options and just like you said, most just end up returning them... I have helped two buddies with just installing a splitter at the cable box and running a long cable along the house sill, or another horizontal seam.
Tack the cable in place on the outside of the house, and poke it up from below the deck!
This is how most cable companies would run it to an exterior room for you anyways, it's perfectly safe, reliable, and CHEAP... my favorite part. ha ha.
If you find a wireless product you like, please post it up. Good luck!