Avoid the 'combo' antennas if you want the best performance. Also, the type TV/Tuner will play a MAJOR roll in recption and stability.
A house type amp will likely be needed also. Asignal too strong is just as bad as too weak and will overdrive a tuner resulting in no picture. If the coax from the antenna is not too long then the pre-amp can be placed in the home and is not necessary to mount on the mast. Both types will be equally effective however.
I use 3 antennas, one VHF and two UHF for reception from 2 different cities and have for years. While you can use 30 year old antennas, DON'T unless it is brand new old stock. Existing 30 year old antennas that have been out in the weather will likely need replacement as with anything else, they too have a life-span and 30 years old is pushing it. Also DO NOT use twin flat lead wire, use coax RG6 only. Finally, ground not only the coax but THE ANTENNA ALSO MUST BE GROUNDED as well.
Generally speaking, getting 100 mile reception aren't going to happen without very large antennas and tropo conditions (look it up). Certainly won't be very reliable/stable unless you are up high enough (or on the side of a mountain) as the curvature of the earth comes into play after 60+ miles.
Finally, be prepared...something as simple as a leaf on a tree can cause multipath and thereby reducing reliability factors. I had an idiot MSO owner try to tell me that leaves on trees (or lack thereof) do not affect reception and it wasn't untill after I was gone that he realized that I knew what I was talking about. Sometimes you can have an antenna too high just as too low and not get reception. DTV/ATSC is a finicky bitch, not like the old NTSC system where it would ghost.
Post back if you have more questions. And go to this site to purchase antennas: Solidsignal.com
