Terk antenna...that might be part of the problem. Those things are terrible.
As for indoor antennas, I've found this one is the most effective. Nothing fancy looking, just a good old amplified antenna that does the job. Works better than any Terk or "stylish" one.
RCA - Amplified HDTV Antenna - ANT525
Radio Shack also sells one that looks almost the exact same, but only has 22 db of amplification. That one works pretty well too, depending on how much amplification you need.
Being in an area like NYC could cause multipath issues and stuff depending on if you've got large buildings near you. Although they're generally worse for digital than analog. Are all the NYC ATSC stations at full power? And yes...are they VHF or UHF...because that will make a difference.
In my area (Buffalo NY), when using the proper antenna, the digital stations are just as easy, if not easier, to pick up compared to the analogs. The reason I mention "proper antenna" is the amount of people I hear complaining that it doesn't come in well, it'll never work, blah blah blah. Then I find out they're still using rabbit ears, when all of our digital stations are UHF. And the rabbit ears never gave them a good signal in the first place.