These adaptors will plug into your USB modem connection with 3G antennas to extend the signal range.
Usually the current antennas used on your current USB modem are extremely small and provide low signal so adding one of these with a 3G antenna will boost your signal greatly.
SMA to Induction 3G Plug 510mm Cat. AR-3330
SMA Adaptor To HUAWEI E160/618 Plug 500mm Cat. AR-3332
SMA Adaptor To SIERRA TS9 Plug 500mm Cat. AR-3334
SMA Adaptor To TELSTRA 4G USB Modem Lead 490mm Cat. AR-3336
Low Loss SMA Extension Lead 5m Cat. WC-7824