"ml" wrote in message
...
In article , Dave
wrote:

ml wrote:
hi

i have a general shielding question i realize that overall it
might be a impractical thing to build but looking at it i
wonder...

ontop of my roof is elevator room it's about 20x20

flat roof

lets suppose the motor controller throws out 1.7 to 30mhz at
s9+ (all over)

lets say i take a single 20x20 sheet of copper put it on the top
roof (assume i could ground it if need be)

lets say before i put the copper i measured s9

what shielding if any might i see "S" wise??

i understand interference would still be radiating form the rest
of the unshielded structure but wondering if measuring ontop of the
copper sheeting id' observe any attenuation?? meaning would the
signal penatrate that copper? -- and if so around how
much??(alot/very little)


tnx

I'd try bypassing and choking the wires going to the motor and the
controller.

thanks for the help Dav, i sorta feared a simple sheet wouldn't do
much but wanted to double check

seems the device does not radiate along the power lines it just
radiate s of the device itself

it's about 12x12 x12 inches or so the motor controler is inside a
tight heavey metal cabinet the only rf measured is from that
device itself

my thought is to perhaps find a way to build copper mesh 'box' i
can place over it perhaps that would do the trick? it has to be
mesh as the controller gets pretty hot and is fan cooled

galvanized 'hardware cloth' that has about 1/2" mesh is plenty good for that
and can be easily soldered.