X-GM-THRID: 1238683102978290637 X-Gmail-Labels: rsgb lf Delivered-To: daveyxm@gmail.com Received: by 10.78.172.11 with SMTP id u11cs209409hue; Fri, 8 Jun 2007 04:30:27 -0700 (PDT) Received: by 10.82.156.12 with SMTP id d12mr5166654bue.1181302227599; Fri, 08 Jun 2007 04:30:27 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.google.com with ESMTP id h1si2151867nfh.2007.06.08.04.30.25; Fri, 08 Jun 2007 04:30:27 -0700 (PDT) Received-SPF: neutral (google.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1HwccL-0001Qo-4E for rs_out_1@blacksheep.org; Fri, 08 Jun 2007 12:26:57 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1HwccK-0001Qf-O5 for rsgb_lf_group@blacksheep.org; Fri, 08 Jun 2007 12:26:56 +0100 Received: from smtp803.mail.ird.yahoo.com ([217.146.188.63]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1HwccG-0006Cn-2h for rsgb_lf_group@blacksheep.org; Fri, 08 Jun 2007 12:26:56 +0100 Received: (qmail 55176 invoked from network); 8 Jun 2007 11:25:46 -0000 Received: from unknown (HELO Dave) (dsergeant@btinternet.com@86.139.21.103 with login) by smtp803.mail.ird.yahoo.com with SMTP; 8 Jun 2007 11:25:46 -0000 X-YMail-OSG: ZW0E61EVM1mD6sK5F2ZU3FByM5ler6Eex8GcOiuxhuHZ5ChdLIJfrCCII7uICZPooKAg__wORUd22uVFIVr0vSZybdbgHJmygHZTD5UFqomIwGBH From: "Dave Sergeant" To: rsgb_lf_group@blacksheep.org Date: Fri, 08 Jun 2007 12:25:56 +0100 MIME-Version: 1.0 Message-ID: <46694AD4.25449.14C6A73@dave.davesergeant.com> In-reply-to: References: X-mailer: Pegasus Mail for Windows (4.41) Content-description: Mail message body X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: Reinventing Wheels. Wireless Power Transmission - again. Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none 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 Status: O X-Status: X-Keywords: X-UID: 1487 On 8 Jun 2007 at 11:49, Andy Talbot wrote: > *http://news.bbc.co.uk/1/hi/technology/6725955.stm* .uk/1/hi/technology/6725955.stm> > > They clain to have acheived 40% efficiency - that doesn't seem very > good. > > Andy G4JNT > By coincidence there is an article in this month's Engineering & Technology, the magazine of the IET, which discusses these 'power wireless' techniques, it dropped through the letter box this morning. It covers the MIT research and other, inductive coupling and near field techniques, in some depth. They cover how they place resonant receivers in the near field of the radiation and can get 50% or so efficiency at short ranges. But there is absolutely no mention of what they do to stop the radiation getting any further - and the only mention of frequency is 'a wavelength of 30m' at one point, which sounds suspiciously like our 30m band.... You really do have to take with a pinch of salt how much these chaps actually claim to know. Another technique involves burying a sheet of resonant coils underneath the floor of the building to couple the rf into the room. The editor has added a snide remark at the end 'If the public is unwilling to allow mobile phone masts to be built close to schools, it seems unlikely they'll welcome the installation of underfloor grids delivering large amounts of power'. Hopefully this will kill these cloud cuckoo ideas stone dead... In due course you will be able to read the article at http://www.theiet.org/engtechmag (only the May edition is there at the moment). 72 Dave G3YMC http://www.davesergeant.com