Return-Path: Received: (qmail 23374 invoked from network); 17 Jul 2001 16:51:21 -0000 Received: from unknown (HELO murphys-inbound.servers.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 17 Jul 2001 16:51:21 -0000 Received: (qmail 13892 invoked from network); 17 Jul 2001 16:49:53 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 17 Jul 2001 16:49:53 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 15MXy3-0002XJ-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 17 Jul 2001 17:45:03 +0100 Received: from irwell.zetnet.co.uk ([194.247.47.48] helo=zetnet.co.uk ident=root) by post.thorcom.com with esmtp (Exim 3.16 #2) id 15MXy2-0002XE-00 for rsgb_lf_group@blacksheep.org; Tue, 17 Jul 2001 17:45:02 +0100 Received: from abc (man-s287.dialup.zetnet.co.uk [194.247.45.158]) by zetnet.co.uk (8.11.3/8.11.3/Debian 8.11.2-1) with SMTP id f6HGiKg28050 for ; Tue, 17 Jul 2001 17:44:21 +0100 Message-ID: <001c01c10edf$777d97e0$9e2df7c2@zetnet.co.uk> From: "John Rabson" To: rsgb_lf_group@blacksheep.org References: <7D653C9C42F5D411A27C00508BF8803D55C558@pdw-mail-r1.dstl.gov.uk> Subject: LF: Re: (E)LF Antennas - railway lines Date: Tue, 17 Jul 2001 17:40:43 +0100 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 5.00.2919.6600 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: ----- Original Message ----- From: "Andrew Talbot" To: Sent: Tuesday, July 17, 2001 2:51 PM Subject: LF: ELF Antennas - ground loops tested. > Presumably other ideas for antennas were also tried back then. > Some years ago, with permission from the railway company concerned, some tests were done in Wansford Tunnel on the Nene Valley Railway. The tunnel is 550 metres long and straight, 7 metres high and 7.5 metres wide. It runs through oolitic limestone and is lined with Victorian brick. It contains two standard gauge railway tracks, one of which runs only about 150 metres into the tunnel and is used in winter to store rolling stock in the dry. John Hey's cave radios on 87 kHz worked well from one end of the tunnel to the other, using loop aerials. It made no difference whether the loops were placed between the running rails or at the side of the tunnel, or in the 6 foot space between the two tracks. A full write-up appeared in: Rabson, John (1998), Underground Radio Tests on the Nene Valley Railway, CREGJ 32, p27, Jun 98. If anyone would like to know more about these tests, I would be happy to talk to them on 01394 460298 or via email, word.factory@zetnet.co.uk.