Radar beacon

The radar beacon (Mechanist device before installing it in Ada) is a miscellaneous item in the Fallout 4 add-on Automatron.

Gameplay
The beacon is a device the Mechanist installed on her robobrains to pinpoint their location. The Sole Survivor can attach one to Ada and use it to locate them.

Location
General Atomics factory, taken from the remains of a servomech robobrain during A New Threat.

Related quest

 * A New Threat