How many TV’s are you feeding?
How long is the cable from the antenna to the TV(s)?
What ground blocks, splitters, junctions, wall plates, etc. are between the antenna and the TV’s.
With the low signal strength for the phoenix stations, cable losses need to be carefully weighed against noise from a preamp. (I know you said preferably without a preamp, but if you have more than 3dB of losses, the right preamp could make a positive difference.)
Which Phoenix stations do you want? The best antenna for RF15 may not be the best antenna for RF51.
(The fox station you are getting on RF26 is SD; look at KUTP on rabbit ears.
http://www.rabbitears.info/market.ph...&callsign=kutp )
If fox is your white whale, you could chase it on RF25, RF26 (in SD), or RF10. For RF25 or 26, either would be in the range where the 422HD or the HD8800 have the best gain (as modeled by
http://www.hdtvprimer.com/ANTENNAS/comparing.html ). If you want to go after RF10, you could try a Y10-7-13.
(I have never captured a VHF channel with a negative noise margin, but I have gotten several UHF stations with negative modeled noise margins. That probably has something to do with it being easier to make a high gain UHF antenna that is a reasonable size.)