It would only make sense, after seeing what a kitchen strainer and aluminum foil can do, that a metal kitchen pot would provide a significant signal boost for a mobile broadband modem, or "dongle." The homemade video evidence tells all.
The video is edited in a rather stuttered style for reasons unknown, but the segments where a USB broadband modem is placed into, and pulled out of, a large saucepan, with a signal strength meter running, seem to be fairly steady. A YouTube commenter suggests a more parabolic shape, like a wok, might do even better in capturing and honing the broadband signal.
If you're ever stuck at a friend's house with weak mobile broadband reception, it might pay off to dig into their cookware. At the least, it's an instant conversation starter.