"Dave Plowman (News)" wrote in message
...
In article , charlie
wrote:
The main problem with plastic bodied cars is interference from the car
ignition, etc. On others the engine is in a sort of Faraday cage.
Hence the earthing straps you often see across the bonnet (hood)
hinges. Although this is mainly for the benefit of others to prevent
RFI to TVs etc. But it helps the car radio too.

huh? there's plenty of holes around the engine so that it's not a
faraday cage.

A Faraday cage can be made of mesh. Doesn't have to be solid steel.

holes, as in multiple square feet. that's pretty loose mesh. faraday cage
holes are sized to the wavelength of the frequencies that are to be blocked.

http://en.wikipedia.org/wiki/Faraday_cage

"Cars and airplanes. When lightning strikes an airplane or a car the
electric currents induced on it are forced to travel on the outer skin of
the vehicle's body. Other signals such as cell phone signals penetrate the
skin of cars and airplanes because the wavelength of the signal is
significantly smaller than the holes present on the surface of the conductor
(the windows)."

to claim that the surrounding car body panels of a car engine is a faraday
cage is just incorrect. faraday cages simply can't have holes or they leak
the signals, making the cage be useless. a cage either is complete, and it
works, or is incomplete, and doesn't work. in the latter case, if it doesn't
work, why would manufacturers pay to engineer and make, and we have to pay
to haul around forever, an incomplete cage?

most radios have some sort of filter for this.

Some sort of, yes. But it's still better to stop interference getting to
the aerial - especially for distant reception.

for that matter, my vette doesn't have any of these and the radio works
in it.

I didn't say it wouldn't 'work' Only that it won't work as well as in a
metal bodied car unless some form of alternative screening is used.

--
*If horrific means to make horrible, does terrific mean to make terrible?

Dave Plowman London SW
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