I ordered the RCA ANT751R then started researching

I haven't put it up yet, but plan to mount it on a chimney that is not being used. It will be about 15-20' above ground.
Here is the link to my signal results
http://www.tvfool.com/?option=com_wr...1dda3f0182c29a
I'm not sure if the antenna that I purchased will be strong enough. If not, do you have suggestions. I can return the ANT751R if I need to and purchase something else. Should I purchase an amplifier because I am splitting the signal between 3 TV's.
I have purchased, but haven't received 50' rg6 coax cable, a ronard chimney mount, and a 5' mount extension.
I am mostly interested in local channels 2-12. Just to see what I could get, I tried hooking up the 751R inside my house-sitting next to my TV, but didn't get any channels. My house is older and it's difficult getting signals through walls etc. Should I have been able to get something though? I'm afraid that I'm hooking something up incorrectly.
Thanks