Back when the Lumia 925 launched some thought that having the antenna in the metal band around the phone would affect the reception, leading to a death grip as was the case with the iPhone 4. Thankfully as Jay demonstrated in one of the hands on videos, that is not the case with the 925
Nokia conversations have written a bit on the subject detailing why the 925 won’t be plagued with the same issues:
On the Lumia 925, the aluminium ring around the phone actually act as parts of the phone’s radio antenna system. The main antenna is located in the bottom area of the phone and two more towards the top of the phone. There are then stripes that separate the antennas from the other parts of the metal ring.
The end result is that you’ll get equally good radio performance out of the Lumia 925 as you would from a wholly polycarbonate phone, plus the most important benefit in the form of a stunning design.
Of course, if you deliberately use two hands to cover every edge of the phone, you’ll manage to reduce the signal. But that’s true of any other phone, too. You may also find it a little tricky to operate the buttons that way!
So technically you have nothing to worry about folks.