The biggest problem with indoor antennas is local interference. In my home, I have computers and lots of other sources of broadband noise. I found that the best spot in my home office wasn't by the window at all, but in a corner kind of behind a metal shelf that aforded some shielding to the local noise sources. Get a portable radio, tuned to the desired station and walk around listening for the best reception. You can then place your dipole andenna in about the same spot and try for improved reception. Sometimes the best spot is pretty far away from the reciever. If that's the case, use a piece of coax to get to the best antenna location and then attach your dipole to the end of the coax, using a balun if necessary.