I would like to get a an outdoor tv antenna for my grandma and I am choosing between an arrow antenna a bowtie antenna which would one work the best. She lives in a blue to purple on the tv fool scale?
At least give the zipcode. A bow tie antenna is UHF only an "arrow" antenna is both VHF and UHF in most cases but can be VHF only. We need correct info to give you a good educated guess.
A good 4 bay as high as you can get it should be enough for the Dayton stations. Cincinnati has a VHF-hi station that would require a larger antenna with that capability.