digex@world.std.com (doug e humphrey) (04/13/91)
I am building out a computer room in my basement, to hold all of the fun machines that are sitting around running and producing bad EMI. Not a real problem before, but now I am getting into shortwave and other DXing, and suddenly my basement seems like a bad place to receive anything at all. Since it is basically new construction, it might be the time for a faraday cage type of enclosure. Since my chances of getting the local fusion lab to cut an enclosure loose for me are low, I will have to do it myself. References as to books on the subject (leaning toward the practical, since I want to get this done fairly quickly) and places to obtain materials would be welcomed. Ways to cover the power lines and phone lines coming in, and of course the data lines going out of the room would be useful too, etc. Thanks. Hope this is a fun discussion for all of you too! Doug Humphrey Digital Express Group Crypto Systems Division (this week...)
agengcc@unx2.ucc.okstate.edu (Gordon Couger) (04/13/91)
In article <1991Apr13.031643.3772@world.std.com> digex@world.std.com (doug e humphrey) writes: > >I am building out a computer room in my basement, to hold all of >the fun machines that are sitting around running and producing >bad EMI. Not a real problem before, but now I am getting into (stuff deleted) I would start by getting some thin sheet iron (not galvinized zink fumes will kill you) cut them out to fit floor walls and ceiling and solder all the joints. Cover the windows with hail screen and electricaly connect it to the walls. Doors should be plated with steel and connected to the sheild. All power lines should be in conduit properly grounded. Ideally the computer room should have its own electrical service on a seperate transformer. Ferrite chokes and rf opto-isolation of all rs232 lines and parallel would be nice. The lines should be carried in conduit grounded only at the computer end. I would think that isolation of the computer ground and the radio ground would be very helpful. This is best performed on the third day of the new moon accompanied by the sacrifice of an administrator, an elected official or a any number of lawyers. Battery powered computers seem to cause me less trouble in the shack. Gordon agengcc@unx2.ucc.okstate.edu (Gordon Couger) D the sacrifice of an admistrator or the sacrifice opto-isolation bypass capacitors across the AC at every outlet. Opto isolation conduent > B A B B >since I want to get this done fairly quickly) and places to obtain >materials would be welcomed. Ways to cover the power lines and >phone lines coming in, and of course the data lines going out of >the room would be useful too, etc. > >Thanks. Hope this is a fun discussion for all of you too! > >Doug Humphrey >Digital Express Group >Crypto Systems Division (this week...)
bame@hpfcbig.SDE.HP.COM (Paul Bame) (04/15/91)
Conductive paints have been advertised for the purpose of shielding rooms at reasonable cost. I know nothing of their performance and only dimly remember seeing an advertisement in Radio Electronics (no doubt there are lots of ads in the right Industry rags) within the last 6 months. -Paul Bame bame@hubble.sde.hp.com N0KCL
robf@mcs213k.cs.umr.edu (Rob Fugina) (04/18/91)
In article <6560012@hpfcbig.SDE.HP.COM> bame@hpfcbig.SDE.HP.COM (Paul Bame) writes: >Conductive paints have been advertised for the purpose of shielding >rooms at reasonable cost. I know nothing of their performance and This reminds me... I would venture to say the most effective way to sheild a room is to line the walls with lead... (This comes from the fact that I work (over the summer...I'm a student) in a hospital lab which is located where the radiology dept used to be located... we couldn't pick up a radio station if the transmitter were accross the street! Rob
Nandu@cup.portal.com (Narendra J Kulkarni) (04/24/91)
There is a wallpaper like covering made from iron/metal shavings, I have seen it used to shield rooms for FCC testing. It is fairly cheap about 50c/sq.ft and comes in different strengths probably based on conductivity. If u need more info send me e-mail at nitinj@chips.com and I will send more info
charlies@hpnmdla.hp.com (Charlie Sallberg) (04/25/91)
We recently built a "low-cost" shielded room here at HP for an antenna testing range, using two layers of foil-backed wallboard on both sides of the metal 2x4 framing (4 layers of foil total). The seams of the foil were taped with 4-inch wide aluminum tape. The seams of the two layers on each side of the wall were also staggered. The ceiling was done the same way, and for the floor, sheet aluminum was laid down, again taping all seams between panels and where the floor meets the wall. I measured > 60 dB of shielding effectiveness at 1, 5, & 10 GHz for these walls. Handling the penetrations for lighting, other electrical, doors, etc. is the trickiest part of any shielded room, but others have already made some good suggestions for some of those. I believe the foil-backed wallboard is generally available anywhere, as I think it's designed to provide a vapor barrier for normal construction. Charlie