WNYT's main transmission is on channel 12 from the Community Tower in the Helderbergs, where most of the major locals are. Channel 18 is a repeater at their old location on Bald Mountain, a.k.a. Mount Rafinesque.
I too get dropouts from ch. 12, about every 16 seconds reliably, but only on one kind of tuner (SiliconDust HDHomeRun). I don't get dropouts with other tuners using the same antenna system, nor does the HDHomeRun have a problem with ch. 18 when I point an antenna in that direction. I haven't figured out what causes it.
I've never used a TiVo so I can't help you there. Most of the systems I have used allow me to tell them that I get station x on channel y. Maybe the TiVo has a way to do that.
I'm surprised that you can get ch. 6 with the RCA ANT751; it looks like it's intended for UHF and maybe some high VHF, but if it works, it works.
Here are a few links I've found useful for finding out about local broadcast stations:AntennaWeb
lets you zero in on your location on a street map and shows directions to the stations relative to your streets, which simplifies antenna aiming. But it's conservative in what it thinks you can get and may not list all the stations in the area.TV Fool
doesn't give you the handy street map, but Zip+4 should be accurate enough. It takes terrain into account (but not buildings and trees) and I trust its results more than AntennaWeb's. It also offers a download of a Google Earth overlay showing where all of the US TV transmitters are.RabbitEars
has a ton of technical information about US and Canadian broadcast stations. Although I gave the main page here, I find the site map
easier to navigate.
The SiliconDust Lineup Server
will show you what others in your postcode are able to receive with the company's HDHomeRun tuner, from both antenna and cable (and FIOS where available).Antenna basics
and Comparing some commercially available antennas
from HDTVPrimer give good tips on what kinds of antennas have the best chance of working under various conditions.