I think what is being talked about here is normally referred to as an 'RF shield box'. There are lots of them around for testing cell phones, bluetooth devices and such. We found one used last year for a few hundred dollars - try dovebid or ebay. We also built a larger one for laptops and small systems out of 80/20, with galvanized sheet steel for sides and lined with RF absorbent foam. OTOH the OP may be talking about an 'RF screen room (or box)' aka 'Faraday Cage'. Depends on what they are trying to do/measure. We've also built on= e of those out of 80/20 and copper mesh. There are several screen rooms on ebay TEM and GTEM cells are yet another animal. Gary On Thu, Oct 14, 2010 at 11:10 PM, Xiaofan Chen wrote: > On Fri, Oct 15, 2010 at 6:46 AM, Richard Prosser > wrote: > > > I haven't made one but we have some small ones here at work that don't > > look too difficult to copy. > > > > I'd start with an old microwave oven and add absorbent material. The > > hardest part may be finding something suitable. The boxes we have here > > are lined with a carbon loaded foam (at least that's what it looks > > like) but we still get reflections from it. You have to be careful to > > position the DUT in exactly the same location each time & not rely on > > the results too much! (Final tests are done in a proper chamber). > > > > If you can afford it, I think it's a case of bigger is better, and the > > more absorbent material you can squeeze in the better also. > > > Interesting. I thought all these chambers were worth > half a million to several million US dollars. But I > was only thinking of standard 3m and 10m chamber > for EMC/EMI testing. Our 3m chamber is under > construction so that I can avoid to go for evening > testing in outside test lab. > > -- > Xiaofan > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 ---------------------------------------------- Gary A. Crowell Sr., P.E., CID+ Linkedin Elance --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .