OTA signal strength

[mdl23]

I recently put up a vhf/uhf outdoor antenna that I bought at Radio Shack. It works great. I was wondering though if I need to adjust it a little. I am getting a signal strength between 85% and 90% on most of my locals, but one or two of the channels sometimes jumps from 90% all the way down to 70% for about 1/2 a second and jumps back up in the 80's. Is this a broadcast signal issue or my antenna? I have a Dish 811 and live in the dallas/fort worth metro area. I don't have any large buildings or towers between my home and the tv towers.

 

[boba]

Sounds more like an 811 problem.