Return-Path: Received: from rly-mg03.mx.aol.com (rly-mg03.mail.aol.com [172.20.83.109]) by air-mg07.mail.aol.com (v121_r4.4) with ESMTP id MAILINMG071-a0549248ecb107; Wed, 19 Nov 2008 17:10:29 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-mg03.mx.aol.com (v121_r4.4) with ESMTP id MAILRELAYINMG037-a0549248ecb107; Wed, 19 Nov 2008 17:10:23 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1L2vFE-0006rP-8X for rs_out_1@blacksheep.org; Wed, 19 Nov 2008 22:09:56 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1L2vFD-0006rG-ML for rsgb_lf_group@blacksheep.org; Wed, 19 Nov 2008 22:09:55 +0000 Received: from smtp815.mail.ird.yahoo.com ([77.238.189.20]) by relay3.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1L2vFC-0008WI-Qv for rsgb_lf_group@blacksheep.org; Wed, 19 Nov 2008 22:09:55 +0000 Received: (qmail 94726 invoked from network); 19 Nov 2008 22:09:49 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btopenworld.com; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE:In-Reply-To:Importance; b=luMIwHFNi7tGPJyI0QK+eR+UsPKAPtZYoWdWlqxS60596XnxQx9xctNmOWaQrOJ+lOpEjLtTrb9gggRffUrB/x8ZFwb3WWMlimxgnnRshWfS2pD37sS4oo+3vT5wVlgVNaa+LR1uMeA/72upvjP01/zpQanmwSsp16NXqCWl/Vk= ; Received: from unknown (HELO aquarids) (ganymede444@81.153.225.4 with login) by smtp815.mail.ird.yahoo.com with SMTP; 19 Nov 2008 22:09:48 -0000 X-YMail-OSG: IEXio1IVM1k53LyTj.UveflvDiQl21Y0wqW2aU3TstBm2KYEOVX3Y3._f36GgvY4xKn.cbFfdZwRpVyf6YWuEuxeiWhc_JggI7Q3g.2eTIxg0LQiq9VS0ds9Uc8KSW7T6mZtWLLmnO_Esy2_buyzLPkPfpZEaeU9gdAJRvTTHU7NsbmDpQKKiDFiFQg- X-Yahoo-Newman-Property: ymail-3 From: "Dave G3WCB" To: Date: Wed, 19 Nov 2008 22:11:19 -0000 Message-ID: MIME-Version: 1.0 X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2911.0) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1914 In-Reply-To: <001e01c94a77$cc1fa780$a402a8c0@Inspiron> Importance: Normal DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: RE: 3C85/90 Toroids Content-Type: multipart/alternative; boundary="----=_NextPart_000_0037_01C94A93.BFB66760" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.4 required=5.0 tests=FROM_ENDS_IN_NUMS,HTML_40_50, HTML_FONTCOLOR_BLUE,HTML_MESSAGE 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-IP: 193.82.116.20 ------=_NextPart_000_0037_01C94A93.BFB66760 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit MessageHi, Lee, LF I have found that the core material used for the output transformer and feedpoint choke isn't too critical in push-pull FET transmitters like the G0MRF and other designs. I've used a variety of dodgy toroids made from EMC-choke grade material with good results. However, you absolutely do need to use the right material for the 56-uH inductors in the low-pass filter, otherwide they heat up alarmingly. As well as the famous Phillips 3C85 material, I find that Micrometals toroids type T130-2 (1.3 inch) and T200-2 (2-inch) toroids work quite well at 137 kHz. I bought some from a stall at Kempton Park rally, and I'll post the name of the vendor here just as soon as I can remember who it was! You can also use air-cored solenoid windings for these inductors, but if you use wire that is too thin, they will also heat up as the circulating currents within the LPF can be quite high. Look out for them at rallies if you get the chance. The T130-2 and T200-2 toroids are coloured red with one grey cheek. Good luck and 73 Dave G3WCB IO91RM -----Original Message----- From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Lee Hudson Sent: 19 November 2008 18:51 To: rsgb_lf_group@blacksheep.org Subject: LF: 3C85/90 Toroids Hi, Any suggestions for suppliers of Toroids made from 3C85/90 material rather than stripping down old SMPS? 73, Lee M0LMH ------=_NextPart_000_0037_01C94A93.BFB66760 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
Hi,=20 Lee, LF
 
I have=20 found that the core material used for the output transformer and feedpoint c= hoke=20 isn't too critical in push-pull FET transmitters like the G0MRF and other=20 designs.  I've used a variety of dodgy toroids made from EMC-choke= =20 grade material with good results. However, you absolutely do need to use the= =20 right material for the 56-uH inductors in the low-pass filter, otherwide the= y=20 heat up alarmingly.
 
As=20 well as the famous Phillips 3C85 material, I find that Micrometals toro= ids=20 type  T130-2 (1.3 inch) and T200-2 (2-inch) toroids work quite well at=20= 137=20 kHz. I bought some from a stall at Kempton Park rally, and I'll post the nam= e of=20 the vendor here just as soon as I can remember who it was! You can also use=20 air-cored solenoid windings for these inductors, but if you use wire that is= too=20 thin, they will also heat up as the circulating currents within the LPF can=20= be=20 quite high.
 
Look=20 out for them at rallies if you get the chance. The T130-2 and T200-2 toroids= are=20 coloured red with one grey cheek.
 
Good=20 luck and 73
 
 
Dave=20 G3WCB IO91RM
-----Original Message-----
From:=20 owner-rsgb_lf_group@blacksheep.org=20 [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Lee=20 Hudson
Sent: 19 November 2008 18:51
To:=20 rsgb_lf_group@blacksheep.org
Subject: LF: 3C85/90=20 Toroids

Hi,
 
Any sugg= estions=20 for suppliers of Toroids made from 3C85/90 material rather than stripping=20= down=20 old SMPS?
 
73,
Lee=20
M0LMH=
 
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