Is the 3rd floor the top floor ? Does the apartment building length ways north and south ? Is the apartment on the north end of the building ? If yeses then so much the better for you. I am thinking that the indoor tv antenna will work just fine inside of the apartment. However if a tv antenna needs to go outside then ,
http://www.amazon.com/Parts-Express-.../dp/B0002KR74A . If you do use this coupler , do not Slam the door or window on the coupler - be nice to it. As you go through life think about where the tv transmitters are at and where the tv receive antenna is at. The less obstructions the better.