The simple test for this is to hold the remote at the same height and orientation but not near your head. This has no range increasing effect. Similarly you can hold it in the same as normal orientation but against your torso... range will be improved.
Try these things... I have. I stand...
One of the main components of any radio tuner is called the "LC Tank" or "LC circuit". http://en.wikipedia.org/wiki/LC_circuit It's a very simple circuit and the frequency it resonates to (is tuned to) is given by:
f = 1/(2*pi(sqrt(LC)))
You can't really have much effect on "L"...