I've seen it discussed before, but not to any "real" conclusion. I have 2 different Apple Airport cards here. Both support N, but one is a 2 antenna, and the other is a 3. I have done a 3rd antenna mod, so it's no biggie to me now, but what does the 3rd antenna really do for me? Does it add resilience to the signal? I haven't seen a bandwidth difference with 2 vs 3. I do notice the 3 runs hotter than the 2. Is it (3rd antenna) neccessary? On the airport cards, the antennae are slightly different sizes. Are they for the different frequencies?