Press information To download a text file of this release and a ZIP file of 300dpi print quality images, go to www.parkfield.co.uk/winkelmann Article for Nick Morris, Electro Optics, Military & Security feature Apr/May issue Covert and overt sound monitoring using a fibre optic-based microphone Stephen Read Winkelmann UK Military, police and intelligence services often need to carry out both overt and covert surveillance of rooms or premises as part of their duties, with the capture of sound or images for the area the objective of the exercise. Overt monitoring, for instance in interrogation rooms, is an obvious requirement in order to capture a verifiable record of the conversation; covert monitoring is designed to achieve the same objective, but with the added complications of access to the target premises and the avoidance of detection once the microphone or camera has been deployed. A further complication, when using microphones either overtly or covertly, is positioning the device so that conversations are recorded irrespective of the position of the people holding a conversation in the room relative to the microphone, the quality and veracity of the recording so that individuals can be identified and the immunity of the device to interference from extraneous sources of electrical noise. In covert operations, where the equipment has to be installed in a potentially hostile environment, immunity from detection is a critical further consideration. In some cases, for instance where employee fraud is suspected, a company's management may well authorise the installation of covert surveillance covering the offices of assumed perpetrators, so all that is required is that the device is unobtrusive. For such applications, the Winkelmann UK Kingfisher Security Optical Microphone (SOM) is already used by many law enforcement agencies throughout the world. Unlike conventional microphones, the construction of which renders then readily detectable using conventional detector during a counter surveillance sweep, the SOM uses fibre optic technology and an extremely small 6mm diameter head which, when installed, is invisible to all but the most rigorous and painstaking visual search of the premises. The principle of operation is relatively simple: light from a remote LED is transmitted via optical fibre - which can be up to 1km long - onto a reflective membrane mounted a few millimetres from the output of the fibre. Sound waves in the room disturb the sensitive membrane, modulating the reflections from it, which, obviously, in turn modulate the electrical signal from the photo detector, the output of which can be recorded onto a suitable HDD, FLASH memory or other media. The output is extremely high fidelity, the unit offers S/N ratio in excess of 58dB @ 1 kHz 94dB SPL and the microphone is omni-directional. All equipment, other than the microphone unit itself, is located well away from the area being monitored. The microphone can be embedded in the wall or ceiling or hidden behind existing lights, wall switches or power sockets. The robust fibre optic links can run in existing cable ducts or through any convenient route: over the ceiling, under the floor or though the wall. The unit is completely immune to RFI interference, often a major source of induced noise in conventional equipment: it also renders the unit transparent to normal methods used to detect the presence of covert surveillance devices. Whether used as a back-up device supporting other overt recording technology, as a covert unit or as an overt, albeit concealed, device, the combination of innovative opto technology with advanced signal processing and conditioning has produced a device with many advantages over more traditional approaches; the recordings achieved are of sufficient quality to be admissible as evidence in legal proceedings if required. For applications where evidence gathering is the primary objective, the high quality of the captured sound recording and the wide coverage achieved by the unit make it a very useful addition to the equipment portfolio. Using the same principle as the SOM is the recently introduced Fibre Optic Stethoscope, FOS, which is particularly useful when anti-terrorist or SWAT teams need to capture sound information rapidly when, for example, they need to free hostages. The FOS allows security professionals to listen and record through concrete walls, windows and doors without the need to be inside the room, simply by attaching the microphone to the wall or door using Bluetack or a similar material. Despite the sound being attenuated through the structure of the building, the quality and veracity is excellent. *** Ends: body copy 684 words *** Notes to Nick Morris 16 March 2006. Copy and images supplied by email. For further information: Stephen Read Winkelmann UK Ltd Unit 59, Rowfant Business Centre Wallage Lane Rowfant RH10 4NQ tel: + 44 (0)1342 719024 fax:+ 44 (0)1342 719030 sales@winkelmann.co.uk www.winkelmann.co.uk Agency contact: Nigel May Parkfield Communications Ltd Parkfield House Damerham Hants SP6 3HQ tel: + 44 (0)1725 518321 fax: + 44 (0)1725 518378 nigel.may@parkfield.co.uk www.parkfield.co.uk Winkelmann UK is a global leader in the design and manufacture of counter surveillance equipment for use by government agencies, the armed forces, law enforcement organisations and commercial organisations.