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This is real folks. With the advent of cell-phones the potential for problems has increased dramatically. Even folks who are well grounded (no pun intended) in electrical/electronic systems are not as familiar with this subject as they could be. While not a new field, in recent years EMC (ElectroMagnetic Compatibility) and EMV (ElectroMagnetic Vulnerability) have come to be recognized as a major area of concern. The forgotten shield or ground wire, even an extra ground in the wrong place by a well meaning person. A forgotten screw (commonly called a pocket screw) or even a screw of the wrong type metal can cause a higher than intended impedance. Too high a impedance can allow too high a voltage to be developed across it. That can result in a spark - even a tiny spark can ignite fumes. There was always more reason than just the engine running to set the rule to shut your engine off while refueling. It usually turned off any electronics, especially transmitters. Now that you hold a transmitter in your hand, independent of the engine running and regardless of how low power the transmitter is, people gotta' think. You wouldn't light a match in a gas fume environment - don't operate electronics either. It's not just the spark of it's own on/off switch, it's the induced current flow it can create in an otherwise passive device. This isn't to say only improperly maintained items are vulnerable, although they are more so. But even new stuff. Every possible scenario cannot be engineered into every item. If they tried you couldn't afford anything. And remember, it's not the fault of the transmitter (except maybe the operator using it when they shouldn't). The transmitter is merely doing what it's supposed to do. It's the 'victim' device that's at fault - shielding, bonding, grounding etc.
I speak true - this is the field I earn my living in. I just covered it lightly here, I could speak volumes on it.

Charliej



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