Things to Consider
When using an external antenna, you are disabling the internal antennas of your device. Hotspots have anywhere from 2-8 internal antennas to simultaneously connect to multiple cellular frequencies. By using an external antenna you will be limiting yourself to a single antenna. In cases of poor signal, an external antenna can make a huge difference, because the antennas can be placed outdoors, etc. But if you have medium to excellent signal strength, an external antenna may have negative effects on your service speeds.