Return-Path: Received: from rly-da10.mx.aol.com (rly-da10.mail.aol.com [172.19.129.84]) by air-da02.mail.aol.com (v125.7) with ESMTP id MAILINDA021-a984af1fadf26d; Wed, 04 Nov 2009 17:06:45 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-da10.mx.aol.com (v125.7) with ESMTP id MAILRELAYINDA108-a984af1fadf26d; Wed, 04 Nov 2009 17:06:25 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1N5nyp-0007uE-A8 for rs_out_1@blacksheep.org; Wed, 04 Nov 2009 22:05:27 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1N5nyo-0007u5-PU for rsgb_lf_group@blacksheep.org; Wed, 04 Nov 2009 22:05:26 +0000 Received: from mtaout02-winn.ispmail.ntl.com ([81.103.221.48]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1N5nym-0000Os-7a for rsgb_lf_group@blacksheep.org; Wed, 04 Nov 2009 22:05:26 +0000 Received: from know-smtpout-3.server.virginmedia.net ([62.254.123.3]) by mtaout02-winn.ispmail.ntl.com (InterMail vM.7.08.04.00 201-2186-134-20080326) with ESMTP id <20091104220518.PGRU27507.mtaout02-winn.ispmail.ntl.com@know-smtpout-3.server.virginmedia.net> for ; Wed, 4 Nov 2009 22:05:18 +0000 Received: from [86.31.61.6] (helo=[192.168.1.64]) by know-smtpout-3.server.virginmedia.net with esmtpa (Exim 4.63) (envelope-from ) id 1N5nyg-0006GL-Gx for rsgb_lf_group@blacksheep.org; Wed, 04 Nov 2009 22:05:18 +0000 Message-ID: <4AF1FA9D.8070804@virgin.net> Date: Wed, 04 Nov 2009 22:05:17 +0000 From: Ian Marsh User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <9afca2640910310528p4f07557aifdc0557a68bfeff8@mail.gmail.com>, <002b01ca5c10$0ccec4f0$0201a8c0@Clemens04> <4AF1B717.31461.F2160F@mike.dennison.ntlworld.com> In-Reply-To: <4AF1B717.31461.F2160F@mike.dennison.ntlworld.com> X-Cloudmark-Analysis: v=1.0 c=1 a=7b43F8AYrcwA:10 a=aSRvjw2BAAAA:8 a=CgNqllsWG-05WrqzYUIA:9 a=2GBL2JHnIdRHs7xvi9KQYDiXSw4A:4 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: Re: 500kHz attenuation graphs? Content-Type: text/plain; charset=ISO-8859-1; format=flowed 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 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) Wonder if this would help. It's a free BBC document on the estimation of LF/MF broadcast service areas. There are graphs for the 200 KHz to 1500 KHz region for differing ground conductivities. It's available at: http://downloads.bbc.co.uk/rd/pubs/reports/1975-01.pdf Older editions of the NAB Engineering Handbook at least had graphs for the MW broadcast band if I remember correctly but someone seems to have lifted our work copy and the latest edition is priced at $199. Cheers Ian / G4EXD