Re: Impedance Shielding Eff.
Hi Captain, You will be able to when we finally document what we're up to. There is a potential patent in the way we do the testing. The bad side is not that we can't disclose it yet, but that we're not in a position to generate revenue from it...;- Maybe by the time we meet in CA this summer. Derek. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Impedance Shielding Eff.
Hey Derek - Don't be shy. Can't we be all party to some of the dos donts?? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Impedance Shielding Eff.
There is an ASTM (I do not recall the number) for just your purpose. The jig is an expanded piece of coax, with a slot into which a puck of the test material may be inserted. If the material is a perfect conductor, it shorts the input and you get no output. If the material is a perfect insulator, you get 100% transmission. In between, you can relate the percent transmission to SE (dB). I bet someone reading this knows the number and can cite a source for the jig. The jig and technique were developed at NBS (now NIST). Note that this is purely a measure of far field SE. Ken Javor -- From: Antonio Cinquino cinqu...@cae.ca To: emc-p...@majordomo.ieee.org Subject: Impedance Shielding Eff. Date: Wed, Jan 17, 2001, 11:27 AM Dear Group, I have a task assigned and I don't know where to begin. I'll be as descriptive as I can and look forward to hearing your comments/suggestions. Within our company it has been suggested that the fiberglass body that acts as a structural support (a sort of canopy) be impregnated with copper mesh to give it shielding properties. It will be used to provide extended shielding of some electronics inside. My question is with regards to determining the following: 1) the shielding effectiveness (near and far field) 2) Impedance over frequency (up to 500Mhz) (I've seen several plots of impedance over frequency for grounding straps and system reference potential planes, does anyone know how these plots are formed, measurement or calculation?) What has been put on my desk is several pieces of fiber glass about 1ftx1ft. One has the wire mesh impregnated, one has a conductive coating, the other has, i think a mixture of the two, (by the way the overall structure of the final product will be irregular and fairly large) Can any one suggest to me a quick test jig that I can setup to help determine the above two points (using the 1ftx1ft fiber glass and required measurement equipment). This would help determine which of the three fiberglass pieces is best. I'm not sure what this question might sound like to the rest of you. I guess I'll figure it out from the responses :) Thanx in Advance Best Regards, Antonio L. Cinquino CAE Electronics Ltd. Electrical System Designer Phone : (514) 341-2000 (ext. 4303) Fax : (514) 340-5552 Pager : (514) 897-5166 Email : mailto:cinqu...@cae.ca cinqu...@cae.ca --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Impedance Shielding Eff.
Ken, a jig like you describe was made and marketed by Elgal in the USA. It was called a SET 19 I believe. Derek. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Impedance Shielding Eff.
Antonio, When I was a little younger, we tested a bunch of panels to help determine the make up of an aircraft structure. Our panels were about 10 by 18. We did the testing by putting the panel in the shared wall between two shield rooms, creating a field in one, then measuring the field in the second. It was done, with and without the panel in place. Needless to say we learned a bunch of things NOT to do;-). There are a bunch of test houses, including mine, that can do this test. The difficulty is getting the correct interface between the panel and the room wall. If you want to know more about the in's and outs of this testing, talk to me off line. Best regards, Derek. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Impedance Shielding Eff.
Dear Group, I have a task assigned and I don't know where to begin. I'll be as descriptive as I can and look forward to hearing your comments/suggestions. Within our company it has been suggested that the fiberglass body that acts as a structural support (a sort of canopy) be impregnated with copper mesh to give it shielding properties. It will be used to provide extended shielding of some electronics inside. My question is with regards to determining the following: 1) the shielding effectiveness (near and far field) 2) Impedance over frequency (up to 500Mhz) (I've seen several plots of impedance over frequency for grounding straps and system reference potential planes, does anyone know how these plots are formed, measurement or calculation?) What has been put on my desk is several pieces of fiber glass about 1ftx1ft. One has the wire mesh impregnated, one has a conductive coating, the other has, i think a mixture of the two, (by the way the overall structure of the final product will be irregular and fairly large) Can any one suggest to me a quick test jig that I can setup to help determine the above two points (using the 1ftx1ft fiber glass and required measurement equipment). This would help determine which of the three fiberglass pieces is best. I'm not sure what this question might sound like to the rest of you. I guess I'll figure it out from the responses :) Thanx in Advance Best Regards, Antonio L. Cinquino CAE Electronics Ltd. Electrical System Designer Phone : (514) 341-2000 (ext. 4303) Fax : (514) 340-5552 Pager : (514) 897-5166 Email : mailto:cinqu...@cae.ca cinqu...@cae.ca attachment: Image8.gif
