For the signal conditions reported, the HD7698P is an appropriate choice. If you need to remove the antenna from the attic for any reason, you'll also want to consider using an Antennacraft HBU-55 which would be easier to re-fold without damage.
Do you have trees in the area?
If you mount outside, a J-pole is not going to be sturdy enough to support a large antenna. I would opt for chimney, gable, or tripod style mounting. Regardless of the exact type of mount, the antenna is going to do best if it's given a clear view toward the transmitters.
www.3starinc.com
http://www.solidsignal.com/c/product...ennas-supplies