Aw, geez! John is right. I was thinking about ground leads which are grounded in operation, like the straps that connect engine and mount, or mount and air-frame.
Of course, when the engine is running, the mag leads are part of the 'hot' side (the P-lead), and are unterminated antennas with standing waves on them. Therefore, they are going to be a MAJOR source of crackle into the things behind the panel, unless you ground them, in which case the engine quits :-) When is a ground not a ground? When the engine is running! Greg At 10:35 AM 10/15/99 -0400, John Cooper wrote: >"Not so, grasshopper!" > >To anthropomorphize things, every time the mag points open, the collapsing >field makes a current run down that wire to the switch looking for a path to >ground. When it gets to the open switch (mag "on") it turns around and runs >back to the high tension side and fires the plug. While all this is >happening, a magnetic field builds up around the wire and then collapses. >The shielding is to prevent this field from escaping into the real world and >interfering with your radios. (Non-electric, assumed NORAD planes typically >didn't have or need shielding; excess weight.) You'll need shielding from >the mag to the switch housing. The switch itself should be shielded too, >alternatively it can be enclosed in a metal box to which the shield is also >connected. > >John
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