Delivered-To: daveyxm@virginmedia.com Received: by 10.50.237.98 with SMTP id vb2csp7952igc; Sat, 8 Mar 2014 09:37:19 -0800 (PST) X-Received: by 10.180.9.51 with SMTP id w19mr2172634wia.27.1394300238548; Sat, 08 Mar 2014 09:37:18 -0800 (PST) Return-Path: Received: from post.thorcom.com (post.thorcom.com. [195.171.43.25]) by mx.google.com with ESMTP id wi6si14069042wjb.168.2014.03.08.09.37.18 for ; Sat, 08 Mar 2014 09:37:18 -0800 (PST) Received-SPF: neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) client-ip=195.171.43.25; Authentication-Results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) smtp.mail=owner-rsgb_lf_group@blacksheep.org Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1WMKhQ-0005Nf-Uj for rs_out_1@blacksheep.org; Sat, 08 Mar 2014 17:06:12 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1WMKhQ-0005NW-IB for rsgb_lf_group@blacksheep.org; Sat, 08 Mar 2014 17:06:12 +0000 Received: from parrot.netcom.co.uk ([217.72.171.49]) by relay1.thorcom.net with esmtp (Exim 4.82) (envelope-from ) id 1WMKhO-0005xn-7K for rsgb_lf_group@blacksheep.org; Sat, 08 Mar 2014 17:06:11 +0000 Received: from sb.abelian.org (i-194-106-52-83.freedom2surf.net [194.106.52.83]) by parrot.netcom.co.uk (Postfix) with ESMTP id 4101F3273EF for ; Sat, 8 Mar 2014 17:04:41 +0000 (GMT) Received: from [127.0.0.1] (localhost [127.0.0.1]) by sb.abelian.org (Postfix) with ESMTP id 5FB7D28A0AB9 for ; Sat, 8 Mar 2014 17:06:09 +0000 (UTC) Message-ID: <531B4E01.7000304@abelian.org> Date: Sat, 08 Mar 2014 17:06:09 +0000 From: Paul Nicholson User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <2662DF5AA7FA416CBB09CDB90BBFF7B1@White> <016101cf39df$4f4c89a0$ede59ce0$@comcast.net>, <01dc01cf3a3f$86997bb0$93cc7310$@comcast.net>, <2FC5CAB271A6437CB35A5B100185CEDA@White> <025101cf3a52$e0925750$a1b705f0$@comcast.net> <7DB9DD5669FC4C648838510DCAC08AFB@White> <531A506E.9040103@abelian.org> <531A5C19.9060209@abelian.org> <02ba01cf3aa3$debaad50$9c3007f0$@comcast.net> <531AF126.2060600@abelian.org> <850A470A5B9F4483BED8B49D4791044A@White>,<531B1D0C.3070208@abelian.org> In-Reply-To: X-Spam-Score: 0.7 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Bob wrote: > Wonder what effects soil conductivity changes has on the > propagation at these VLF freqs?? I have no information. You would expect ground resistance to rise, but would that make noticeable difference to propagation if it is only a freezing of a shallow surface layer? [...] Content analysis details: (0.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [217.72.171.49 listed in list.dnswl.org] 0.7 SPF_NEUTRAL SPF: sender does not match SPF record (neutral) X-Scan-Signature: 5c335215f1b3de26d890ee84d49616ce Subject: Re: LF: Daytime 29.499 kHz 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=0.9 required=5.0 tests=FROM_ENDS_IN_NUMS 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 Bob wrote: > Wonder what effects soil conductivity changes has on the > propagation at these VLF freqs?? I have no information. You would expect ground resistance to rise, but would that make noticeable difference to propagation if it is only a freezing of a shallow surface layer? I had to go to a narrower bandwidth to produce phase and amplitude plots for last night's test http://abelian.org/vlf/tmp/29499_140308a.gif Signal is down by some 5dB compared with some recent tests. Nothing detected this afternoon. Propagation seems normal, noise floor normal. Maybe the cold and frozen ground is affecting the tx efficiency, some lower Q of the loading coil - antenna - ground loop, or a reduction of effective height. Will be interesting to see what happens after the thaw. -- Paul Nicholson --