I used this amplifier as part of the
Wilson Vehicle Booster Kit for two years in a 17' fiberglass trailer. The external antenna was (and still is) the Wilson short trucker antenna (#301133). This was for voice and data on a AT&T iPhone & data, using a USB stick combined with a WiFi Ranger router.
There are limitations - the boosted signal is only available within 5'-7' feet of the internal antenna, and as doci noted, it is 3G only. The advantage is it will amplify multiple phones & multiple carriers, all at the same time. I have the Wilson antenna mounted on the rear driver's side of the trailer & the internal antenna in the front passenger side.
Because I have switched to 4G for data, I have switched to a Wilson Sleek amplifier. It provides far more gain than the Vehicle Booster Kit, however you must place the phone or hotspot in the cradle. You also have to use the switch on the Sleek to choose AT&T or Verizon, and, of course because it is a cradle, you can only amplify one device at a time.
Another limitation of the combination of the Sleek & the Hotspot is it cannot directly connected to the WiFi ranger router. While the hotspot does produce a WiFi network, it is not as strong as the WiFi Ranger's WiFi output, limiting the working distance. Since I often use the cell based data source while driving, I preferred the stronger router.
