Return-Path: Received: (qmail 14977 invoked from network); 18 Nov 2002 07:48:58 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 18 Nov 2002 07:48:58 -0000 Received: (qmail 27504 invoked from network); 18 Nov 2002 07:49:59 -0000 Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 18 Nov 2002 07:49:59 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18DgeL-0000la-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 18 Nov 2002 07:48:53 +0000 Received: from [212.1.130.1] (helo=smtp-1.visp.telinco.net) by post.thorcom.com with esmtp (Exim 4.10) id 18DgeK-0000lR-00 for rsgb_lf_group@blacksheep.org; Mon, 18 Nov 2002 07:48:53 +0000 Received: from [212.1.153.103] (helo=pcuser) by smtp-1.visp.telinco.net with smtp (Exim 3.32 #1) id 18DgWw-0000vA-00 for rsgb_lf_group@blacksheep.org; Mon, 18 Nov 2002 07:41:15 +0000 Message-ID: <000301c28ed6$ee352100$679901d4@pcuser> From: "Hugh Burnham" To: rsgb_lf_group@blacksheep.org References: <3DD35969.30941.58250D@localhost> <004801c28bb7$b2c00580$015e89d9@jackie> <5.1.0.14.0.20021114135046.02a5e660@pb623250.kuleuven.be> <000b01c28c92$7ca50aa0$0504210a@c.scope> <002901c28c9a$c4c9b1c0$ac2765d5@oemcomputer> Date: Mon, 18 Nov 2002 07:47:55 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2919.6600 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: LF: Re: Re: Calibrating LF Current Meters Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=0.5 required=5.0tests=REFERENCES,SPAM_PHRASE_00_01,USER_AGENT_OEversion=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Thankyou Johan, Rik, Stewart, Alan, Dave, Alex and others, for giving me your thoughts. I like Dave's "quick and dirty" way, which is basically what started out by doing, except that I relied on the rig's power meter to give me 50W which, using I squared R, gives 1 Amp. I'm using a pair of ferrites from a TV scan coil yoke, so I can clamp them round any conductor that needs measuring. I compared the readings on the 160m and 80m bands, but found that I got different readings on the two bands. The reading was less on 80m - indicating some loss. A coil wound on a nice RF ferrite toroid gave the same readings at both frequencies. I expect the scan coil ferrites would be ok at 136kHz, but it didn't inspire confidence in my calibration technique. It is really a case of pulling myself up by the bootstraps, because the TX is an unknown quantity at the moment, so it looks like I need to press on with that to get a good source of current, to test the meter, that I wanted to test the TX amp with ! You're right, Alan, I'll just be looking for changes (increases) to start with - so I can worry about fine tuning it later. Think I'll borrow a scope from work and then I can do the job properly. Thanks once again. 73 Hugh M0WYE.