Earlier quoted context omitted.
I don't know about that last point. I live about 45 miles from Philly and 55 miles from NYC. I get pretty much all of the stations from both with minimal drop and I have a $35 antenna inside in my attic.
I'm curious about the antenna you're using. I'm also approximately equidistant from NYC and Philly, but I tried a digital antenna once, and could only pick up one NJ station, and none of the NYC or Philly ones. I'd love to find an antenna that works!
Try the "coat hanger antenna" (google it). It's directional enough to be effective. There are some tweaks you can make to it to adjust how directional it is. (Adding more elements, or doubling it mainly.)
It's very cheap so you can experiment.
You'll need one of those impedance converter thingies to convert from twin lead to coax.