Return-Path: Received: (qmail 2321 invoked from network); 7 Mar 2002 09:56:53 -0000 Received: from unknown (HELO warrior.services.quay.plus.net) (212.159.14.227) by exhibition.plus.net with SMTP; 7 Mar 2002 09:56:53 -0000 Received: (qmail 7588 invoked from network); 7 Mar 2002 09:56:50 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior.services.quay.plus.net with SMTP; 7 Mar 2002 09:56:50 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16iw0E-0006hE-00 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 07 Mar 2002 11:24:06 +0000 Received: from carbon.btinternet.com ([194.73.73.92]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16iw0D-0006h9-00 for rsgb_lf_group@blacksheep.org; Thu, 07 Mar 2002 11:24:06 +0000 Received: from host62-7-31-127.in-addr.btopenworld.com ([62.7.31.127] helo=dave) by carbon.btinternet.com with smtp (Exim 3.22 #8) id 16iuTH-0004li-00 for rsgb_lf_group@blacksheep.org; Thu, 07 Mar 2002 09:45:59 +0000 Message-ID: <002301c1c5bd$240e6ae0$7f1f073e@dave> From: "Dave Sergeant" To: "rsgb_lf_group" References: <3C865D9F.6FD91638@netscapeonline.co.uk> <002801c1c551$ab585400$1700a8c0@home> Subject: LF: Re: Re: loops Date: Thu, 7 Mar 2002 09:42:38 -0000 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: >From Dave G3YMC >The main problem with transmitting loops is the enourmous current and >Voltage which is generated when exciting them with decent power. It's all >very well to put 1W into a loop but try 1kW and see what happens..... High Q >(which you MUST have for good efficiency) necessarily means high Voltage and >current. This is true, but as WE0H comments the biggest problem is current rather than voltage. Calculations on my loop (not that much smaller than 40 ft square...) indicate that 26A would be required at 400W input. Using my method of capacitive matching this would probably be unrealistic as the demands on the capacitors would be excessive. The current handling of the conductors is probably the least of the worries. I am currently driving my loop at 80W, and it seems quite happy at that level. Dave G3YMC dsergeant@iee.org dsergeant@btinternet.com http://www.dsergeant.btinternet.co.uk