Thread: hf shielding
View Single Post
  #3   Report Post  
Old October 7th 08, 10:19 PM posted to rec.radio.amateur.antenna
ml ml is offline
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 225
Default hf shielding

In article ,
Jim-NN7K . wrote:

More effective to build a Faraday Cage around the elevator room
(service techs use these for RF tight enclosures).
Jim NN7K

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


wanted to thank everyone for responding and offering some tips

just a few FYI's

I doubt i could afford or be allowed to build a 'cage' around the
entire room

The motor emits to noticable noise

the motor controller in the cabinet aka magnetek600 sure does.

i would be easy i guess since it's rather small um loaf of
bread sized to build a copper mesh around it i was considering
going to a a/c place and have them do it professionally


measuring w/my ft-817 and a small hand held spectrum analyzer i
measure almost no noise along the input power lines nor any
out to the motor there is 1 sensor cable to the motor also
no noise all are run in seperate conduit

best as i can measure that is

appreciate all the help folks