Ah, I remember when I was working for Verizon when a similar line of Moto phones came out (maybe five years ago) and there was an actual external antenna that you could buy to juice the signal a bit. Here’s how to make your own. This actually looks to improve the signal quite a bit — even moreso than the add-on that was available.
2day’s How-To: Boost Your Cellular Signal [2day Blog]