Another problem is height of their antennas so you need to get yours as high as possible. 6 inches HAS made a difference on my attic mount from an unreliable 70ish reading to a solid mid 80s for me on nbc/abc. If you are 16 miles out and can't get a decent nbc/abc, then that's not good. Higher UHF numbers are harder to get, but you are 'so' close it shouldnt be too much a problem unless you have a blocked signal
here's some data of interest
uhf station signal power height 26 (cbs3) 90-92 770/375 31 (pax61) 90-91 32 (upn 57) 75-80 250/400 34 (wbye35) 80-85 358/377 42 (fox 29) 25-45 305/161 54 (wb 17) 60ish 500/354 64 (abc 6) 85+ 500/390 67 (nbc10) 85++ 560/377
as you can see, fox sucks!
Also note in order to just test a signal you dont have to run guided setup, if you haven't done it already. The channels will test just fine.
also, as Ironwood people can be horrible...i'd stay away from their antenna/installers and ask a friend or even go the yellow pages for a good antenna/installer.