Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dk02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 42BA038000108; Wed, 23 Jan 2013 15:57:40 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Ty7Mt-0006IS-RG for rs_out_1@blacksheep.org; Wed, 23 Jan 2013 20:56:23 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Ty7Mt-0006IJ-CT for rsgb_lf_group@blacksheep.org; Wed, 23 Jan 2013 20:56:23 +0000 Received: from mail-ie0-f172.google.com ([209.85.223.172]) by relay1.thorcom.net with esmtps (TLSv1:RC4-SHA:128) (Exim 4.77) (envelope-from ) id 1Ty7Mr-0003kq-NE for rsgb_lf_group@blacksheep.org; Wed, 23 Jan 2013 20:56:22 +0000 Received: by mail-ie0-f172.google.com with SMTP id c13so14548367ieb.3 for ; Wed, 23 Jan 2013 12:56:00 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:content-type; bh=BuCWnf5KriKd+fZL33VaAmZC/RO6vvgna94S0va0ptQ=; b=pnd2PaBYAMcFCJDf02j5cqLWYub7x3igJ1bSSMPHBxWMAc1zzP3ezGOPYGEP/v+d75 9xlVvJLMs/rt5V4GvVDCra0v34Wy2yEakylWJeBft9maIg4N4UHfMh9PNcfcpmZKujZJ sZSc/uSuhj8pZSlp1I0cZbinctGYE5Lvote9bo0rTMzEhWWv2bl13Mcg+/fvco1Tsyxm vfC2TFa709OU9Wix4vkUbYk0sVD9BvJwfJY1tn37I91tiFWfKtxV3ySA4GWKXPmkmcFk OFjcpGMfPRBLF/Bhucinwozj0/RpMldq94Ahik1f08zKHxjEBWH7Pi5ndVAlFr3o/F+e NmAw== MIME-Version: 1.0 X-Received: by 10.43.114.135 with SMTP id fa7mr2057339icc.21.1358974560054; Wed, 23 Jan 2013 12:56:00 -0800 (PST) Received: by 10.231.149.195 with HTTP; Wed, 23 Jan 2013 12:56:00 -0800 (PST) In-Reply-To: <91F6C305-52EE-44ED-9307-A2645290EB00@gmail.com> References: <91F6C305-52EE-44ED-9307-A2645290EB00@gmail.com> Date: Thu, 24 Jan 2013 07:56:00 +1100 Message-ID: From: Dimitrios Tsifakis To: rsgb_lf_group@blacksheep.org 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: Hi Roger, > Thank you for publishing your results. Most interesting. What sort of power does your antenna analyser put out? I checked the manual and it seems the antenna analyser produces +13 dBm (20 mW) on a 50 ohm load. [...] Content analysis details: (-0.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [209.85.223.172 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (dtsifakis[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: f62c7cf8eeb8e5a327b71719e9bffff1 Subject: Re: LF: earth antenna test Content-Type: text/plain; charset=ISO-8859-1 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-global-disposition: G X-AOL-SCOLL-AUTHENTICATION: mtain-dk02.r1000.mx.aol.com ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1db40651004ec4740c X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Hi Roger, > Thank you for publishing your results. Most interesting. What sort of power does your antenna analyser put out? I checked the manual and it seems the antenna analyser produces +13 dBm (20 mW) on a 50 ohm load. > Can you remind us what sort of soil/rock geology you have there? It sounds like it may have similar properties to mine here where the 2 earth rods separated by 20m look close to 60 ohms resistive. The dominant type of geological formation under the soil is shale. The soil is not very deep, in some places there is no soil, in others it can be over a metre. We have had some really hot days here, so the ground is quite dry, which probably affects its resistivity. > Here, I have not tried wires on the ground unterminated although I can only manage 15-20m max in my small garden. This feels like the ideal portable antenna, doesn't it! My next test will be a full dipole on the ground which, if it works as well, is more convenient as there is no requirement for earth stakes. > This week I hope to measure my 137kHz field strength from my earth-electrode antenna and 8W beacon at about 10km (to get ERP) by comparing the level against the strong Greek commercial signal near the band which I am told is about 1mV/m in the UK. That's a good way to derive an absolute field strength for your signal! > We have lots to learn still about earth antennas! We sure do! 73, Dimitris VK1SV