must have more information.
where is the antenna located?
how far away are you from the broadcast tower?
is the antenna amplified?
do you have the new 'decoder' for the digital channels that are broadcasting over the air?
other people in the area might have better antenna location.
but
if their antenna isnt in the attic... or if it isnt outside.
i find it a bit difficult to see how you are not getting a signal but they are.
could be a building blocking reception.
but
otherwise.. it boils down to a high quality antenna, an antenna amplifier, and a good antenna location.