[ROVERNET - UK] Radio static???

Dave Read defender110 at ozemail.com.au
Sun Jul 24 20:32:05 BST 2005

Dennis Brooks wrote:
 > I could see that scenario with steel...but what about aluminum ??

Any "cage" of metallic earthed metal can perform this task.
Called a Faraday cage, it is also the stuff you can see in the door of 
your microvave oven to keep the radiation contained.
Low permeability steel is best at shielding, but just consider, what 
metal is often used in the "shielded" cable connecting your vehicle's 
antenna to the radio? - Copper! (sometimes aluminium)
The "cage" is crudely formed by the matal panels surrounding the engine 
compartment, including the bonnet.

You also wrote
 > Dave...doesn't the engine ground perform this function ??

Engine grounds are important in that they provide a low resitance path 
back to the battery to minimise earth loop induced interference due to 
alternator, injector, computer and starter operations.

The biggest problem with ignition is that you are trying to switch a 
highly inductive coil on and off very rapidly.
In short, highly inductive means "it don't wanna be turned on and off 
quickly", and in retaliation, generates large pulses of radio frequency 

South Oz

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