Chapter I : The rights and duties of neutral powers - Art. 3.
Art. 3. Belligerents are likewise forbidden to:
(a) Erect on the territory of a neutral Power a wireless telegraphy station or other apparatus for the purpose of communicating with belligerent forces on land or sea;
(b) Use any installation of this kind established by them before the war on the territory of a neutral Power for purely military purposes, and which has not been opened for the service of public messages.