Cutting the cable, lets talk options and media setups

So let me ask this question...

Is it possible for one antenna to strengthen another? My dilemma with the Leaf antenna in my bedroom is well-documented in this thread. The other day, I was scanning through channels when all of a sudden, channels that I originally had not had. I had not conducted a re-scan of the channels or anything. The only thing that has happened is the addition of the 2nd TV and antenna in the living room. The placement of both antennas are close to each other with only the wall between them. I always thought that one would interfere with the other, not strengthen it.

In the old days multiple antenna could cause ghosting and other problems. I don't know what would happen now that they're using ATSC.