Quite right, in fact most are grids. You save weight, easier to form etc. There may be one exception: extremly wide band circuits. /Inge -------------------------------------------------- From: "Eric Kalgren" <[log in to unmask]> Sent: den 23 June 2010 18:38 To: "'Inge'" <[log in to unmask]>; <[log in to unmask]> Subject: RE: NTC - [TN] Pewter as RF screening material > It doesn't even have to be a solid sheet of metal, a grid with openings > sized for the lowest frequency you want to block will also work. See > also: the screen keeping all those microwaves in the oven where they > belong. > > I used to work at a facility called "The Trestle" which was used to test > EMP effects on aircraft. The entire test site was completely surrounded > by a wire grid, designed to keep the EMP inside and not turn the city of > Albuquerque off when the EMP generators fired. I never saw any testing > but found a fun article. > > http://www.chucksville.org/trestle.html > > Eric Kalgren > Electrical Engineer > > The Ferrite Co. Inc. > 165 Ledge Street > Nashua, NH 03060 > Phone 603-881-5234 X 153 > Fax 603-881-5406 > PRIVILEGED AND CONFIDENTIAL COMMUNICATION > This E-mail is covered by the Electronic Communications Privacy Act, 18 > U. S. C." 2510-2521 and is legally privileged. The information > contained herein is confidential and is intended only for the use of the > individual or entity named above. If the reader of this message is not > the intended recipient, you are hereby notified that any dissemination, > distribution or copying of this communication is strictly prohibited. > If you have received this transmission in error, please immediately > notify the sender by telephone or via e-mail and delete the original > transmission including any attachments without reading or saving in any > manner > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge > Sent: Wednesday, June 16, 2010 1:53 PM > To: [log in to unmask] > Subject: Re: [TN] Pewter as RF screening material > > Sure you can. Semding you a table with skin depth vs freq and also RF > resistivity for some common metals used in PWBs. Notice the > considerable > differencies. RF designers use to forget this. > Off line. > /Inge > > -------------------------------------------------- > From: "Eric CHRISTISON" <[log in to unmask]> > Sent: den 14 June 2010 16:43 > To: <[log in to unmask]> > Subject: Re: [TN] Pewter as RF screening material > >> "Speaking RF signals at radar levels, magnetrons, >> klystrons, TWTs and other high power sources, I would not use > pewter." >> >> You're talking of peak pulse powers in MW here aren't you? >> >> Can't you figure out a minimum thickness for any screening material > based >> on something like resistivity and loss tangent, it's called skin depth > or >> something? >> >> >> >> >> >> On 14/06/2010 15:18, Mike Fenner wrote: >>> Hmm.... >>> >>> Some lead free solders are not a million miles from pewter. >>> >>> Regards >>> >>> Mike >>> >>> >>> >>> -----Original Message----- >>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge >>> Sent: Thursday, June 10, 2010 7:01 AM >>> To: [log in to unmask] >>> Subject: Re: [TN] Pewter as RF screening material >>> >>> Hi Grant, >>> >>> any METAL case will work. What you create is a Faraday cage, that > will >>> eliminate electrostatic and electromagnetic influence. However, it > will >>> NOT >>> >>> eliminate static magnetic fields, nor low frequency electromagnetic >>> waves. >>> In such a case you'll need ferro materials, one of the best being so >>> called mu metal. But, as your question was about RF, pewter will > work, >>> not >>> as good as ferro materials, but it depends on the pewter wall > thickness. >>> In >>> >>> many modern electronics, you get acceptable RF shielding by means of >>> plastic >>> >>> boxes with a thin metal coating only. Works for weak RF signals, > which >>> are >>> often the case within commercial products like mobile telephones and >>> transistor radios. Speaking RF signals at radar levels, magnetrons, >>> klystrons, TWTs and other high power sources, I would not use > pewter. >>> >>> Inge >>> >>> -------------------------------------------------- >>> From: "Grant Emandien"<[log in to unmask]> >>> Sent: den 9 June 2010 11:22 >>> To:<[log in to unmask]> >>> Subject: [TN] Pewter as RF screening material >>> >>> >>>> Hi, >>>> >>>> Does anyone used lead-free pewter for RF screening purposes? >>>> >>>> Pros& Cons? >>>> >>>> Regards >>>> Grant >>>> >>>> > ______________________________________________________________________ >>>> This email has been scanned by the MessageLabs Email Security > System. >>>> For more information please contact helpdesk at x2960 or >>>> [log in to unmask] >>>> > ______________________________________________________________________ >>>> >>>> --------------------------------------------------- >>>> Technet Mail List provided as a service by IPC using LISTSERV 15.0 >>>> To unsubscribe, send a message to [log in to unmask] with following > text >>>> in >>>> the BODY (NOT the subject field): SIGNOFF Technet >>>> To temporarily halt or (re-start) delivery of Technet send e-mail to >>>> [log in to unmask]: SET Technet NOMAIL or (MAIL) >>>> To receive ONE mailing per day of all the posts: send e-mail to >>>> [log in to unmask]: SET Technet Digest >>>> Search the archives of previous posts at: >>>> http://listserv.ipc.org/archives >>>> Please visit IPC web site >>>> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 >>>> >>> >>>> for additional information, or contact Keach Sasamori at > [log in to unmask] >>>> or >>>> >>> >>>> 847-615-7100 ext.2815 >>>> ----------------------------------------------------- >>>> >>> >>> > ______________________________________________________________________ >>> This email has been scanned by the MessageLabs Email Security System. >>> For more information please contact helpdesk at x2960 or > [log in to unmask] >>> > ______________________________________________________________________ >>> >>> --------------------------------------------------- >>> Technet Mail List provided as a service by IPC using LISTSERV 15.0 >>> To unsubscribe, send a message to [log in to unmask] with following > text in >>> the BODY (NOT the subject field): SIGNOFF Technet >>> To temporarily halt or (re-start) delivery of Technet send e-mail to >>> [log in to unmask]: SET Technet NOMAIL or (MAIL) >>> To receive ONE mailing per day of all the posts: send e-mail to >>> [log in to unmask]: SET Technet Digest >>> Search the archives of previous posts at: >>> http://listserv.ipc.org/archives >>> Please visit IPC web site >>> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 >>> for additional information, or contact Keach Sasamori at > [log in to unmask] >>> or >>> 847-615-7100 ext.2815 >>> ----------------------------------------------------- >>> >>> >>> ***This email, its content, and any files transmitted with it, are >>> intended solely for the addressee(s) and may be legally privileged > and/or >>> confidential. 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They may be subject to change >>> without notice.*** >>> >>> >>> > ______________________________________________________________________ >>> This email has been scanned by the MessageLabs Email Security System. >>> For more information please contact helpdesk at x2960 or > [log in to unmask] >>> > ______________________________________________________________________ >>> >>> --------------------------------------------------- >>> Technet Mail List provided as a service by IPC using LISTSERV 15.0 >>> To unsubscribe, send a message to [log in to unmask] with following > text in >>> the BODY (NOT the subject field): SIGNOFF Technet >>> To temporarily halt or (re-start) delivery of Technet send e-mail to >>> [log in to unmask]: SET Technet NOMAIL or (MAIL) >>> To receive ONE mailing per day of all the posts: send e-mail to >>> [log in to unmask]: SET Technet Digest >>> Search the archives of previous posts at: >>> http://listserv.ipc.org/archives >>> Please visit IPC web site >>> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional >>> information, or contact Keach Sasamori at [log in to unmask] or > 847-615-7100 >>> ext.2815 >>> ----------------------------------------------------- >>> >>> >> >> -- >> Eric Christison Msc >> Mechanical Engineer >> Consumer& Micro group >> Imaging Division >> >> STMicroelectronics (R&D) Ltd >> 33 Pinkhill >> Edinburgh EH12 7BF >> United Kingdom >> >> Tel: +44 (0)131 336 6165 >> Fax: + 44 (0)131 336 6001 >> >> >> >> >> ______________________________________________________________________ >> This email has been scanned by the MessageLabs Email Security System. >> For more information please contact helpdesk at x2960 or > [log in to unmask] >> ______________________________________________________________________ >> >> --------------------------------------------------- >> Technet Mail List provided as a service by IPC using LISTSERV 15.0 >> To unsubscribe, send a message to [log in to unmask] with following text > in >> the BODY (NOT the subject field): SIGNOFF Technet >> To temporarily halt or (re-start) delivery of Technet send e-mail to >> [log in to unmask]: SET Technet NOMAIL or (MAIL) >> To receive ONE mailing per day of all the posts: send e-mail to >> [log in to unmask]: SET Technet Digest >> Search the archives of previous posts at: > http://listserv.ipc.org/archives >> Please visit IPC web site > http://www.ipc.org/contentpage.asp?Pageid=4.3.16 >> for additional information, or contact Keach Sasamori at > [log in to unmask] or >> 847-615-7100 ext.2815 >> ----------------------------------------------------- > > > ______________________________________________________________________ > This email has been scanned by the MessageLabs Email Security System. > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > To unsubscribe, send a message to [log in to unmask] with following text > in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to > [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: > http://listserv.ipc.org/archives > Please visit IPC web site > http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 > ext.2815 > ----------------------------------------------------- > > ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. 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