Hi,
As you probably know, waveguide below cutoff egress only works for non-conductive cables (or rods, etc.). If you run a conducting cable down the waveguide, the structure no longer exhibits waveguide below cutoff behavior. Instead, what was a waveguide becomes the equivalent of a coaxial cable which has no cutoff frequency for you to get below. Stuffing the waveguide with conductive material is intending to replicate the behavior of access via a patch panel. As said below, you must strip insulation off the cable as it through the waveguide so that the conductive stuffing makes good connection to the cable shield. If you run a non-shielded cable through the waveguide, good luck. Stuff the waveguide to reduce the effective aperture of the hole, use ferrites and hope it is good enough. Jim __________________________ James L. Knighten, Ph.D. EMC Engineer Teradata Corporation 17095 Via Del Campo San Diego, CA 92127 858-485-2537 – phone 858-485-3788 – fax (unattended) ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Mazzola, Santo (US SSA) Sent: Friday, March 13, 2009 1:35 PM To: Luksich Mark-TXP763; [email protected] Subject: RE: [PSES] Chamber access Hi, The only thing that I would add to the good comments already made is that a patch panel should always the first choice. As mentioned previously keeping the shield currents inside the room is accomplished by being able to terminate the shields at the patch panel. After determining that the patch panel is the first choice reality sets in and if anything is unique getting special connectors and feed-throughs makes the patch panel expensive and time consuming. The suggestion of pre-drilled holes for whatever is also an excellent way to try and be prepared for anything. That is why it is best to have waveguides and patch panels available depending on the situation. The other thing to know about using the waveguide is that you need to be able to terminate the cable shields to the waveguide for it to be effective. That would mean removing insulation on the cable passing through the waveguide so that the shield directly contacts the waveguide and the shield currents will go to ground at the waveguide. And as mentioned before putting ferrites on the cable also cannot hurt. Also the waveguide needs to be stuffed with conductive material so there won’t be any electromagnetic environment leaking through the waveguide. Santo (Sandy) Mazzola EMC Engineer West Sayville, NY ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Luksich Mark-TXP763 Sent: Friday, March 13, 2009 4:08 PM To: [email protected] Subject: RE: [PSES] Chamber access When I had the chambers built at Motorola / Plantation, I put a patch panel into the side of my chambers and got a number of standard connector in the panel, from USB to DB25 to Firer optic as well as N, BNC, SMA along with a series of pre drilled holes with plugs plugs for "whatever". Due to the local environment (people having 75W base stations at there desk leaking 5W) I specified two door split chambers one for the EUT and one for the test equipment. Mark Mark S. Luksich DMTS - Regulatory Engineering Office: 631-738-5134 Mobile: 631-827-9385 Fax: 631-738-3776 e-mail: [email protected] <mailto:[email protected]> ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Brent G DeWitt Sent: Thursday, March 12, 2009 7:31 PM To: [email protected]; [email protected] Subject: RE: [PSES] Chamber access Hi Ken, Having run a couple of third party labs, I’d suggest you do both, and several of each. The WBC is the penetration of choice for simple fiber optic cables and weird stuff. Make it big enough (and therefore long enough) that you can send arbitrary metallic cables through with a load of snap-on ferrite beads on them (pick the beads of your choice). The patch panel has the primary advantage of keeping shield currents inside the room. There are lots of companies out there selling data filters for standard connectors. On the down side, you will never be able to match all of your customer needs. I’d also suggest that you have a dozen or so of your blank patch panels fabed with just the mounting details and a drawing of these available for customers. No matter how much you try, you _will_ have a customer that needs something unique! Either sell them a blank panel (at a profit) or give away the specs for the panel as a cheap alternative. Many customers will elect to buy the panel. Price appropriately for your operation. Respectfully, Brent DeWitt Westborough, MA From: Ken MacGrath [mailto:[email protected]] Sent: Thursday, March 12, 2009 6:34 PM To: [email protected] Subject: [PSES] Chamber access Hello, We're upgrading our 3 meter chamber and would appreciate any suggestions you might have for running cables into the chamber from the support equipment. We have a wave guide and could put in a patch panel, but before we do that I would like to get some input from the group Thanks! Ken MacGrath _____________________________________________________________________ Core Compliance Testing Services, LLC 79 River Road (Route 3A) Hudson, NH 03051 Business: (603)889-5545 Cell: (603) 892-0620 Web: www.corecompliancetesting.com ________________________________ A Good Credit Score is 700 or Above. See yours in just 2 easy steps! <http://pr.atwola.com/promoclk/10012657 x1219671244x1201345076/aol?redir=http:% F%2Fwww.freecreditreport.com%2Fpm%2Fdef ult.aspx%3Fsc%3D668072%26hmpgID%3D62%26bcd%3DfebemailfooterNO62> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]>
