Before you spend tons and tons of money on a giant antenna, I would try a 4 Bay or 8 Bay UHF antenna, which is flat and can mount on the side of your chimney. I saw a test of UHF antennas from years and years back, and these little 4 and 8 bay UHF antennas work as well or better than the large Yagi's for UHF, which most digital TV channels are on. They are not VHF antennas, but it seems to work fine on those channels, too. I decided to try my $20 antenna to see what would happen. I am 48 miles from the Los Angeles transmitters, and antennaweb says I should only get 7 channels. I get over two dozen, and with subchannels it comes to 112 channels here in Los Angeles. I don't even have an amplier at the antenna. Most signals are 95+. The 4 and 8 bay UHF antennas are inexpensive so you can give one a test, without breaking the bank or spending huge amounts of time putting it up. In fact, in my first test, I just layed it up against the chimney on the roof. You can then go from there. They do like height, so keep that in mind. Google "4 bay uhf", and you can see what they look like. Since you are a little further away, you might try an 8 bay antenna.
Good luck!
Michael