Incorporating: The Wandel & Goltermann EMR-30 orthogonalE field sensor (1-300 volts/meter). Rechargeable battery with charger. Laptop PC and EMCHs surveillance software which sits neatly inside case. The electric field strength in volts/metre is recorded every second and plotted against time from the computer clock. Running time is governed by the laptop at approximately 3-4 hours unless mains is available.Otherwise the EMR-30 will run all day on internal dry batteries. Data can be downloaded in ASCII format for customised presentation. Typical uses are envisaged where the environment needs to be monitored over a period of time before the installation of sensitive electronic apparatus. Also,verification that sporadic transmissions have occurred which may have been responsible for system malfunction. The data output not only shows the level but time of occurrence.