Hello,
I am struggling to find a 4g router that can accept an external 4g antenna to boost signal. does gl inet make one ?
All the 4G routers use mPCI-e modules that have u.FL connectors. You can easily add a u.FL to SMA pigtail and have your antenna.
The Mifi has drilled holes you just have to punch out for such a setup.
On the x750 Spitz, both the external antennas are for the 4G, the wifi antenna is on the board for 2.4ghz, and has a small internal antenna for 5ghz.
For the new Mudi, you would have to drill a hole for an SMA antenna, but you can use the same pigtail setup.
@Johnex OMG thanks for this awesome reply; the spitz looks exactly what I am looking for ! Just to be sure I can replace one or both of the sma antenna with a more powerful one if needed ? Please correct me but the antennas on the spitz look like SMA or are they u.Fl ?
On the Spitz they are SMA 
Hello again
Where can I find documentation on the 4G/LTE modules of the spitz ? Which one to choose for best compatibility in Europe ?