JimHdk..
With all due respect, while your hypothesis is true (pretty much for any wireless device), it is not the relevant/sole cause of this problem. I first noticed this problem in my new iPad3 when I could no longer read my email from my usual location (using my iPad 1). That was when I first discovered this thread and learned that I was not the only one seeing real differences in the iPad 3 and other Apple devices...
In fact my iPad 1 has substantially better performance held in the same way in the identical location. I am unable to make it lose a connection no matter how it is held when in the same physical location..If anything, I expected the iPad3 to have better performance all-round.. but at least as good in the connectivity area...
I've read most of the posts on this thread, and if you check, you will find that there are many who are having the identical problem, some within the same room as their Airport express. There are multiple videos of this some showing a change from 3 bars to none, just by holding the iPad.
In my earlier post, I merely pointed out that it is usually difficult to demonstrate this problem if you are in a very strong signal area. BTW, I've been a licensed Ham Radio operator for 50 years, so I know a little about RF and antennas.