It happens on my SP3 as well. In fact, it also happens on my Acer W700 as well (same configuration: metal body with plastic strip), so I guess its something you cant avoid with this kind of hardware design.I assume along the top edge of SP3 (above camera & all) where it covered by plastic strip, that's where the antenna is, in my case it is very sensitive when come to bluetooth streaming.
Anyone else having the same issue as mine or I am having defective unit?