You'll encounter weak cell signals or no bars (especially if you're an iPhone user in midtown Manhattan) everywhere you go, which is where this CellLynx 5BARz booster ($300) comes in. About the size of a paperback book, you just plug the box into an AC outlet or cigarette lighter and it somehow corrals and amplifies weak signals to create drop-free conversations and speedy Web surfing where you had neither before, on the road or at home.
No, if won't create signal where there isn't any, but it's fairly portable. It comes with a CLA car mount for use in a car — but just remember its dangerous, if not illegal, to use a cellphone while driving. Your cellphone has to be within a couple of feet of the cradle, which must be a transmitter or some sort, but the main receiver/amplifier box doesn't necessarily have to be near a window such as similar (and less portable) cell boosters. It also works with either GSM or CDMA signals. The company guarantees five bars anywhere within your carrier's coverage area. Let us know how that goes.