Initially I need to both contain my RF, exclude other RF and avoid reflecti= ons for development purposes. What I will make up first is a small tube or = box to take an USB RF device at either end. Once I know it is working, it c= an come into open space and deal with other ISM devices. Later, I have anot= her couple of devices that need a bigger box to test for radiated RF.=20 I know I can make a faraday cage based box simply enough but was looking fo= r sources of the foam plus any hints and tips from any other DIY anechoic e= ndeavours. Thanks =20 On 2010-10-15, at 11:33 AM, Gary Crowell wrote: > 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 hundre= d > dollars - try dovebid or ebay. We also built a larger one for laptops an= d > small systems out of 80/20, with galvanized sheet steel for sides and lin= ed > with RF absorbent foam. >=20 > OTOH the OP may be talking about an 'RF screen room (or box)' aka 'Farad= ay > Cage'. Depends on what they are trying to do/measure. We've also built = one > of those out of 80/20 and copper mesh. There are several screen rooms on > ebay >=20 > TEM and GTEM cells are yet another animal. >=20 > Gary >=20 > On Thu, Oct 14, 2010 at 11:10 PM, Xiaofan Chen wrote= : >=20 >> On Fri, Oct 15, 2010 at 6:46 AM, Richard Prosser >> wrote: >>=20 >>> I haven't made one but we have some small ones here at work that don't >>> look too difficult to copy. >>>=20 >>> 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). >>>=20 >>> 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. >>=20 >>=20 >> 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. >>=20 >> -- >> Xiaofan >>=20 >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >>=20 >=20 >=20 >=20 > --=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 --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .