The SPCN310.000 GSM module can be assigned to any mobile network by the insertion ... The unit comes with an external antenna that fits on the cabinet. The modem communicates with a central station ...

The Vanderbilt (formerly known as Siemens Security Products) SPCW101.000 external antenna kit (868 MHz) allows the connection of a GSM or wireless module in a cabinet to an externally mounted antenna ...

Of course, the Electron is just a GSM module tied to a microcontroller, and you can do the same thing with a Pi, some components, and a bit of wire. If you decide to replicate this project ...

This module ... multiple antenna arrays; health related issues of mobile handsets; radio propagation issues, diversity gain, Rake reception; link budgets; cellular network design and deployment ...