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Interference from Radio Frequency Fields
![]() Microwave tower In office areas these fields will be predominately caused by two way radio or mobile phones and general EMI from neighboring equipment. Depending on the type of equipment, radio frequency fields are normally considered to present a hazard to standard office electronic equipment when the field strength exceeds 1 to 3 V/m.
![]() Radio transmission tower Transient Electromagnetic Fields are produced by the switching of inductive loads such as circuit breakers or motors. Lightning will also cause this type of disturbance. A transient signal in a cable produces a radiated emission with a spectral content dependent on the amplitude, rise time and pulse width. The reception of broadband fields at the lower frequencies is mainly via cables, which are electrically long with respect to the wavelength. A cable longer than one quarter of a wavelength will be an efficient receptor. Broadband radiation from transient sources is rarely found to have significant energy at frequencies exceeding 500 MHz.
![]() Two-way radio Most cables act as fairly low loss transmission lines up to at least 10 MHz above which the attenuation increases significantly due to dielectric losses and skin effect. 30 MHz is normally considered the frequency at which EMI becomes a radiated problem rather than conducted. |
SEARCHSearch the entire FMS web site to find exactly the information you want to know:Industry ExperienceHaving performed hundreds of major shielding installations and more than a thousand field surveys, FMS delivers innovation tempered with experience. Just take a look at our list of satisfied clients.Commitment to ExcellenceFMS has been eliminating electromagnetic interference issues in commercial & industrial buildings, medical facilities, and research laboratories for over ten years. Using the latest technology, backed by independent research and development, FMS delivers customized, innovative solutions for the most complex interference problems, worldwide. | |||||
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