Spacing from NMR FREE cabling and networking Helpdesk
 Question by Philip Carter posted 01 Aug 2002
 Spacing from NMR
What is the recommended spacing for network and phone cable from a NMR spectrometer that produces a 270 MHz, 5 gauss field at 2 meters ?
 Answer by Dmitri Abaimov posted 01 Aug 2002
Dear Philip,

Have you considered fiber already?

If my calculations are correct, here is what we have: electrical performance is guaranteed for a CAT5E cable for up to 3V/m electrical field strength. Magnetic field strength does not matter in a sense, but we should consider that at very high frequencies (like 270MHz) there is a conversion ratio between electrical and magnetic field energy. It's approximatelly 30V/m per 1 milligauss. For 5 gauss magnetic field strength the theoretical calculated electical field strength will be ~ 150,000V/m which means that you may be disturbing networks in the entire town ;-).

Then, of course the building architecture details will matter. What is it that the walls are made from? And so on. But the bottom line is: stay as far as you possibly can (and it still may not be far enough). Or consider using fiber optics in this room.

Dmitri Abaimov, RCDD

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