Alright, I fixed the mount hole to be the proper size.

NOTE1 - You'll need a 1/4"x20 screw, I used a 1" and then just used a nut as a lock. Otherwise, you'd need one that is 1/2" long - Lowe's didn't stock that weird size.

NOTE2 - Shelf isn't deep enough for the wire/antenna to be against the wall. I never intended for it to be since it would need to stick out another inch. (If there's demand, I guess I can extend it - but this thing works great.)

I added of the install pic.

Inventor