Post the requested info from here;
I always blame the squirrels. Mostly because they run across the wires spanning my back yard chasing each other incessently. At least they are fun to watch if you can't get reception. Seriously, I haven't had problems in quite a while, though.
It's pretty common but not for every single situation. OP, please try the tips and mainly provide the requested info from the second link so that we may be able to narrow things down and get you a firm solution rather than speculation.