[timgr]

I'm not in the industry, but a few general points -

- Attic mounting is frequently problematic, because of the shielding from the roof and house, and interference from rf sources in the house. At the very least it reduces your antenna's sensitivity a lot, so go big if you want to try it. For UHF-only, that's something like the Antennas Direct DB8e (4' x 4'), high VHF the Antennacraft Y10713 (10' long), and for low VHF HD1850 (15' long). Not a recommendation - just examples. Lots of discussion of this in older posts.

- which channels do you want to receive? You have possible sources in VHF low, VHF high, and UHF. The more bandwidth the antenna covers, the less sensitive it will be for a given size, all other effects being equal.

- your plot will change with the antenna height. 10' is unrealistically low.

- you have an antenna now - try it out in the attic and see what you get. Should be informative - just run a long cable to your TV and see what you get.

hth!