Boost [ANY] LTE/WiMAX Connection

This increased coverage and connectivity to your ISP.

Unscrew and open your WiMAX modem

Make a small hole in the rear panel for RP-SMA connector

See instructional video here

Products for external antenna project for WiMAX modem:
2.5-2.7GHz 18 dBi WiMAX Outdoor Directional Panel Antenna

U.FL Mini PCI to RP-SMA Pigtail Antenna WiFi Cable

TRENDnet Low Loss Reverse SMA Female to N-Type Male Weatherproof Connector Cable

Connect cable to your external antenna

Secure end with waterproof tape

Connect the other end of the connector to RP-SMA port

Find the location that gives the best signal

Mount external antenna in that spot

Here's a simple YouTube video which shows you the steps

Actual video on how to get it done

*Disclaimer:

Make certain you know what frequencies your service provider is broadcasting on when choosing an antenna.