can i use a direct tv satilite antenna on my roof as an outdoor antenna for my tv?

No you can't.

The frequencies and type of signal is totally different.

Don

Well Chong ya got an a on that one. Cheech says yea ya can however it's highly directional and needs to be pointed at a 40 degree angle downwards, in the general directiion of the transmitter,Offset antennae are designed to look towards the equator, hence geostationary satellites.Search F/D ratio on offset antennas.

Yes you have to modify it first. Take off the LNB and replace it with a small piece of wood. Next take a coat hanger and cut it into two 14inch strait pieces. Bend the coat hangers in half to form a v next screw the hangers to the wood in the center of the v where they are parallel like this >< then on the same screws connect a 75 To 300 Ohm Matching Transformer. Hook it to your tv and point the dish in the general direction of the tv towers.