Return-Path: X-Spam-DCC: paranoid 1290; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: *** X-Spam-Status: No, score=3.2 required=5.0 tests=AMATEUR_PORN,BAYES_00, DNS_FROM_AHBL_RHSBL,FORGED_MUA_OUTLOOK autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id t8JAVdRD010583 for ; Sat, 19 Sep 2015 12:31:39 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZdFNX-00073K-Oz for rs_out_1@blacksheep.org; Sat, 19 Sep 2015 11:28:23 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZdFNX-00073B-An for rsgb_lf_group@blacksheep.org; Sat, 19 Sep 2015 11:28:23 +0100 Received: from smtpout06.bt.lon5.cpcloud.co.uk ([65.20.0.126] helo=rgout0106.bt.lon5.cpcloud.co.uk) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1ZdFMT-0001oq-6S for rsgb_lf_group@blacksheep.org; Sat, 19 Sep 2015 11:28:22 +0100 X-OWM-Source-IP: 86.130.247.207 (GB) X-OWM-Env-Sender: alan.melia@btinternet.com X-RazorGate-Suspect: true X-CTCH-RefID: str=0001.0A090201.55FD3872.0016,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-Junkmail-Premium-Raw: score=73/50,refid=2.7.2:2015.9.15.131516:17:73.106,ip=86.130.247.207,rules=__HAS_MSGID, __SANE_MSGID, MSGID_32HEX_LC, INVALID_MSGID_NO_FQDN, __MSGID_32HEX, __HAS_FROM, __PHISH_FROM2, __FRAUD_WEBMAIL_FROM, __TO_MALFORMED_2, __TO_NO_NAME, __REFERENCES, __BOUNCE_CHALLENGE_SUBJ, __BOUNCE_NDR_SUBJ_EXEMPT, __SUBJ_ALPHA_END, __MIME_VERSION, __CT, __CT_TEXT_PLAIN, __CTE, __HAS_X_PRIORITY, __HAS_MSMAIL_PRI, __HAS_X_MAILER, USER_AGENT_OE, __OUTLOOK_MUA_1, __USER_AGENT_MS_GENERIC, __ANY_URI, __URI_NO_WWW, __URI_NO_PATH, AMATEUR_PORN, __SUBJ_ALPHA_NEGATE, __FORWARDED_MSG, BODYTEXTP_SIZE_3000_LESS, BODY_SIZE_2000_2999, __MIME_TEXT_ONLY, RDNS_GENERIC_POOLED, __URI_NS, SXL_IP_DYNAMIC[207.247.130.86.fur], HTML_00_01, HTML_00_10, BODY_SIZE_5000_LESS, RDNS_SUSP_GENERIC, __PHISH_FROM, __OUTLOOK_MUA, __PHISH_SPEAR_STRUCTURE_1, RDNS_SUSP, __FRAUD_WEBMAIL, FORGED_MUA_OUTLOOK, BODY_SIZE_7000_LESS, REFERENCES, NO_URI_HTTPS X-CTCH-Spam: Unknown Received: from gnat (86.130.247.207) by rgout01.bt.lon5.cpcloud.co.uk (8.6.122.06) (authenticated as alan.melia@btinternet.com) id 55F31B5F0084D925 for rsgb_lf_group@blacksheep.org; Sat, 19 Sep 2015 11:26:58 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btinternet.com; s=btcpcloud; t=1442658437; bh=hF8LzVKgbRxa3S5mtojbgbLGaMt0za3TTJ85kh0gF5E=; h=Message-ID:From:To:References:Subject:Date:MIME-Version:X-Mailer; b=ZSX+mZXP8QjPEQts/PVQRWqOwwyNNjhwR2zaRzqjX2BvfaUEFcKIpDTP+dNDwTjiiSlhLVIHqnS+URoLI0aRcRL6s82fT0b5RjC1aY6Mwis76Z1EYZ41S2nuZbqElE5/QCP9UC4NK65/ba+fQkrbOmHKxa9fY7ic2LbYlBDiO3c= Message-ID: <21D465C632E748AEB1B44B29D0A538CA@gnat> From: "Alan Melia" To: References: <001301d0f2ae$fa2eb260$6401a8c0@ehnebrcdvojcgn> Date: Sat, 19 Sep 2015 11:24:24 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 X-HELO-Warning: Remote host 65.20.0.126 (smtpout06.bt.lon5.cpcloud.co.uk) used invalid HELO/EHLO rgout0106.bt.lon5.cpcloud.co.uk - verification failed X-Scan-Signature: ce0e5a4ae990e5a63db3ab7aea21191b Subject: LF: Re: Ground Content-Type: text/plain; format=flowed; charset="iso-8859-2"; reply-type=original Content-Transfer-Encoding: 7bit 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 4102 Sadly Marcin there is probably no answer to your question. Over the early years of LF activity I tried to make sense of the various "recipes" that were floating around. I found that in general they don't necessarily work for you. The reason being that the local ground condition varies widely at different locations and in various weather patterns. The commercial site designs bear little relation to amateur dimensions. Eventually I came to the conclusion that the only way to proceed was to do measurements at your site and see what strategy is the best. The "best" solution will depend very much on the type of antenna you intend to erect above it. The idea that quantities radials are necessary by comparision with 160m and commercial systems is a myth. To be reasonably effective radials need to me of the order of 1/8th wavelength long at least. This is way beyond practical amateur site dimensions. Running one conductor along the ground under a top-wire (of say an inv L) has a positive effect, but often running out more can be a waste of effort and money. Again it depens on your local conditions. These measurements proved that after you reach the diminishing returns point of ground stakes and counterpoises, then increasing the antenna capacity has most effect. It seems counter-intuitive but putting more horizonal wire in the air reduces the "ground loss" !! In my case doubling the capacity halved the "ground loss". At LF in amateur situations the loss resistance is very often not due to grounding but to the effect of the surrounding environment. Commercial station chose open land and do not try to install antenna in the middle of a forest. Amateurs have to deal with building and foliage with the near field range of the radiator. There is no advice in the manuals about this and the condition is not modelled well (or at all !) in simulator packages. Alan G3NYK ----- Original Message ----- From: "Marcin" To: Sent: Saturday, September 19, 2015 8:44 AM Subject: LF: Ground > Hello, > > I'd like to design a ground for 136kHz/472kHz. I have a few hundred metres > of steel tape at my disposal for this. I'd like to find out how deep into > ground 136kHz and 472kHz respectively can go? > How deep do I have to dig the tape for 136kHz and for 472kHz, or what > would > suit both frequencies? > > Thanks in advance. > 73! Marcin SQ2BXI > >