Return-Path: Received: (qmail 11692 invoked from network); 1 Apr 2005 09:45:49 -0000 Received: from unknown (HELO ptb-spamcore01.plus.net) (192.168.71.1) by ptb-mailstore02.plus.net with SMTP; 1 Apr 2005 09:45:49 -0000 Received: from mailnull by ptb-spamcore01.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1DHIjE-000Oq4-0p for dave@picks.force9.co.uk; Fri, 01 Apr 2005 10:46:12 +0100 Received: from [192.168.67.1] (helo=ptb-mxcore01.plus.net) by ptb-spamcore01.plus.net with esmtp (Exim 4.32; FreeBSD) id 1DHIjA-000OpJ-86 for dave@picks.force9.co.uk; Fri, 01 Apr 2005 10:46:08 +0100 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim) id 1DHImP-0005sw-0U for dave@picks.force9.co.uk; Fri, 01 Apr 2005 10:49:29 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1DHIiI-0004Bn-K5 for rs_out_1@blacksheep.org; Fri, 01 Apr 2005 10:45:14 +0100 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1DHIiH-0004Be-Un for rsgb_lf_group@blacksheep.org; Fri, 01 Apr 2005 10:45:13 +0100 Received: from outbound05.telus.net ([199.185.220.224] helo=priv-edtnes40.telusplanet.net) by relay.thorcom.net with esmtp (Exim 4.43) id 1DHIiG-0006qQ-4w for rsgb_lf_group@blacksheep.org; Fri, 01 Apr 2005 10:45:13 +0100 Received: from cognizant1 ([154.5.20.191]) by priv-edtnes40.telusplanet.net (InterMail vM.6.01.04.00 201-2131-118-20041027) with SMTP id <20050401094504.FXSC24971.priv-edtnes40.telusplanet.net@cognizant1> for ; Fri, 1 Apr 2005 02:45:04 -0700 Message-ID: <00ad01c5369f$a0e09560$0201a8c0@private.network> From: "Scott Tilley" To: rsgb_lf_group@blacksheep.org References: <000001c5369a$46212d10$e6a4c593@RD40002> Date: Fri, 1 Apr 2005 01:46:07 -0800 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-SPF-Result: relay.thorcom.net: domain of telus.net designates 199.185.220.224 as permitted sender X-Spam-Score: 0.6 (/) X-Spam-Report: autolearn=no,FORGED_RCVD_HELO=0.05,FROM_ENDS_IN_NUMS=0.516,HTML_MESSAGE=0.001 Subject: LF: Re: RE: TX Cores Content-Type: text/html; charset=windows-1252 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.2 required=5.0 tests=FROM_ENDS_IN_NUMS,HTML_50_60, HTML_FONTCOLOR_UNKNOWN,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-Spam-Filtered: by PlusNet SpamCORE (v3.00) Content-transfer-encoding: 8bit

Mal / Jim

I found that carefully lapping an 'uneven' core pair could render the core useful. I have had success with mine at over 600W DC input. A flat surface like a drill press or table saw would do nicely. Lie a fresh piece of 320 grit paper on it with alittle water and work in down for abit then finish off with a few strokes with finer grit. Alternate the direction you lap to get an even job...

Of course you could just find another piece of 'street ferrite' that is even... But your shack may fill up fast with monitor parts :-)

73 Scott

----- Original Message -----

From: james moritz

To: rsgb_lf_group@blacksheep.org

Sent: Friday, April 01, 2005 1:07 AM

Subject: LF: RE: TX Cores

Dear Mal, LF Group,

No – it is possible to design these transformers with a small air gap, but there does not appear to be a great advantage to doing so because the required number of turns increases, increasing the “copper” losses and offsetting any reduction in core loss. There is always a quite large gap in the original LOPT – often this is produced by inserting plastic film spacers between the core halves. These, and any glue, should be removed so that the core halves fit together perfectly. Sometimes the gap is produced by machining the core legs to unequal lengths, in which case you can’t really use the core in this application.

Cheers, Jim Moritz

73 de M0BMU

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of hamilton mal
Sent: 31 March 2005 13:36
To: rsgb_lf_group@blacksheep.org
Subject: LF: TX Cores

Hi All Jim M0BMU.

Jim ur mod to the G0MRF using a TV line output transformer. Did u leave a gap between the cores or not ?

73 de Mal/G3KEV