Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dg01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 31E89380000D0; Tue, 27 Sep 2011 16:45:44 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1R8eUl-0005Ks-ND for rs_out_1@blacksheep.org; Tue, 27 Sep 2011 21:43:15 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1R8eUl-0005Kj-7e for rsgb_lf_group@blacksheep.org; Tue, 27 Sep 2011 21:43:15 +0100 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1R8eUk-0007np-25 for rsgb_lf_group@blacksheep.org; Tue, 27 Sep 2011 21:43:15 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay2.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id p8RKhCeB022889 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 27 Sep 2011 22:43:13 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id p8RKhCQP022071 for ; Tue, 27 Sep 2011 22:43:12 +0200 Message-ID: <4E823542.90102@iup.uni-heidelberg.de> Date: Tue, 27 Sep 2011 22:42:42 +0200 From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <16BC8B3CA8672445BC2A29B4C14A26D4379ED2AAB4@exlnmb01.eur.nsroot.net> <4DF9EFD1.5010208@iup.uni-heidelberg.de> <1313780109.51443.YahooMailNeo@web111907.mail.gq1.yahoo.com> <9CD1E11E8BC9402CB4AECECAC4088443@JimPC> <1314394178.5030.YahooMailNeo@web111905.mail.gq1.yahoo.com> <1314641183.5605.YahooMailNeo@web111910.mail.gq1.yahoo.com> <4E5CBC9A.5020900@iup.uni-heidelberg.de> <1314705226.37125.YahooMailNeo@web111901.mail.gq1.yahoo.com> <4E5CF192.3040905@legal-medicine.de> <1317076720.22768.YahooMailNeo@web29509.mail.ird.yahoo.com> <1317077173.13177.YahooMailNeo@web29509.mail.ird.yahoo.com> <1317119515.35504.YahooMailNeo@web29502.mail.ird.yahoo.com> <1317119586.50531.YahooMailNeo@web29505.mail.ird.yahoo.com> <4E81B80E.3030201@iup.uni-heidelberg.de> <1317136545.77621.YahooMailNeo@web29513.mail.ird.yahoo.com> In-Reply-To: <1317136545.77621.YahooMailNeo@web29513.mail.ird.yahoo.com> X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: Re: My first ferrite experiments Content-Type: multipart/alternative; boundary="------------050704090302000902070108" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.2 required=5.0 tests=HTML_40_50,HTML_MESSAGE, HTML_TITLE_EMPTY,NO_EXPERIENCE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:438816800:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d41094e8235f82f3c X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------050704090302000902070108 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hi Daniele, Am 27.09.2011 17:15, schrieb Daniele Tincani: > Hello Stefan, > > but maybe the Q is reduced by the aluminium shield! > Do you think the aluminium could be the problem or the distance > between the coil and the core? The wire shouldn't wound directly on the rod. I have a PVC tube above the rod and so the wire is in a distance of about 3 mm to the rod. I used litz wire and got a Q of 485... > I could replace the aluminium tube with a plastic tube, if shielding > is not necessary, but this would not improve the Q if the problem is > the gap between the coil and the core. Just experiment what is the best solution. But the aluminium shield - if used - should be thin and can be applied above the winding in some distance. I know you have much QRM at home so probably an E field shield makes sense here. Anyway you will be bothered by the local magnetic QRM of course. I personally think that a shield is not necessary if you are /p and far away from man made noise. Then, a higher Q helps more than the shield and a Q of 30! > > Are the rods galvanically separated from each other by a thin plastic > tape? What type is the ferrite material? > Yes I put two layers of plastic tape on tips of each rod. The ferrite > material is russian MU400HH. Fine! I also use the same ferrite type and 55 turns. Your cap is surely the best what you can use. So shorten the wires between L and C and measure the Q on 137 kHz. If it is still in the range of 30, i assume the shield causes high losses. Another idea: There is some conducting spray available. Maybe this can help here? No experience with that, just a spontaneous idea... http://it.farnell.com/_/kontakt-chemie-emv-35-200ml/rivestimento-conductive-emv-35/dp/220115 73, Stefan/DK7FC --------------050704090302000902070108 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi Daniele,

Am 27.09.2011 17:15, schrieb Daniele Tincani:
Hello Stefan,
 
> but maybe the Q is reduced by the aluminium shield!
Do you think the aluminium could be the problem or the distance between the coil and the core?
The wire shouldn't wound directly on the rod. I have a PVC tube above the rod and so the wire is in a distance of about 3 mm to the rod. I used litz wire and got a Q of 485...

I could replace the aluminium tube with a plastic tube, if shielding is not necessary, but this would not improve the Q if the problem is the gap between the coil and the core.
Just experiment what is the best solution. But the aluminium shield - if used - should be thin and can be applied above the winding in some distance. I know you have much QRM at home so probably an E field shield makes sense here. Anyway you will be bothered by the local magnetic QRM of course.
I personally think that a shield is not necessary if you are /p and far away from man made noise. Then, a higher Q helps more than the shield and a Q of 30!

 
> Are the rods galvanically separated from each other by a thin plastic tape? What type is the ferrite material?
Yes I put two layers of plastic tape on tips of each rod. The ferrite material is russian MU400HH.
Fine! I also use the same ferrite type and 55 turns. Your cap is surely the best what you can use. So shorten the wires between L and C and measure the Q on 137 kHz. If it is still in the range of 30, i assume the shield causes high losses.
Another idea: There is some conducting spray available. Maybe this can help here? No experience with that, just a spontaneous idea...
http://it.farnell.com/_/kontakt-chemie-emv-35-200ml/rivestimento-conductive-emv-35/dp/220115



73, Stefan/DK7FC
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