Actually, tyschab, in this case with the 7260, it is absolutely necessary to connect an IPEX cable for an external antenna to post #2 on the 7260 card. It will not work properly without it. The 7260 requires two antennas: the internal one that is in the notebook, and an external one that you must supply. The cable costs all of a buck fifty at Amazon.
But until you have that cable in hand, you can defeat the requirement by temporarily putting Scotch tape on pin #51. You won't get good reception, but at least you can work with the WLAN adapter until you get the cable.