Return-Path: Received: from mtain-de04.r1000.mx.aol.com (mtain-de04.r1000.mx.aol.com [172.29.64.204]) by air-me10.mail.aol.com (v127_r1.1) with ESMTP id MAILINME102-8bc54bb1579ff9; Mon, 29 Mar 2010 21:45:03 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-de04.r1000.mx.aol.com (Internet Inbound) with ESMTP id 6A7AC380000A0; Mon, 29 Mar 2010 21:45:01 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NwQUE-0003RX-FU for rs_out_1@blacksheep.org; Tue, 30 Mar 2010 02:43:22 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NwQUD-0003RO-Se for rsgb_lf_group@blacksheep.org; Tue, 30 Mar 2010 02:43:21 +0100 Received: from smtp102.sbc.mail.ac4.yahoo.com ([76.13.13.241]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1NwQUA-0003SM-K7 for rsgb_lf_group@blacksheep.org; Tue, 30 Mar 2010 02:43:21 +0100 Received: (qmail 68101 invoked from network); 30 Mar 2010 01:43:09 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=snet.net; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Reply-To:From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE:In-Reply-To:Importance; b=rT/6QiojhRog7evI5AXwpIJVXLzxfl7inRCVjuB2BxAc3M9V4DDgMypyFz0NWZtkImJ7bGcmV1TyXTTKZF5CswVepyhwJ6rAosmacaBtWu0gyGypDCdXPLtfl4f3HYxWWGC1Toxev0kIN9s8BNnE1Z4qUT1uW5/5R2g2kmGhVa4= ; Received: from adsl-75-58-179-224.dsl.wlfrct.sbcglobal.net (paulc@75.58.179.224 with login) by smtp102.sbc.mail.ac4.yahoo.com with SMTP; 29 Mar 2010 18:43:09 -0700 PDT X-Yahoo-SMTP: .XXmOBOswBCkuxW404eTLsnd.RdCQPge3WAF X-YMail-OSG: GdMuM.EVM1kaoBUHdyjvJtKKbgCs88fWNOv0JwAi9Opw0omMi62zkyvA1uqP16PtVFSzLgxOvWGGnqipeUH3lHKclI.Rbf11hPJ9QDxrzlDTFQ4G6LfDezEmISmRwDO_bxT1Kow7H_Us2hkHJzi.1Mowyl.FaNVjp5xS9wnPO_lmIIv7jEjx5iRlvJ7wwUIoivZt3fI3Q2.0NjaSb51jdMQdPT1tGko7tbzLaXDFvVUSvL2Xtv7fL5YA0FkcnNpqGdIFn3d9GfMnJARSNrboy4e0JflLXvANnXwvmIVfFGy3VBQMpFnD2W_dMjcag7PjzcjtA.4fKjPRCA_68b6Jfmk- X-Yahoo-Newman-Property: ymail-3 From: "Paul A. Cianciolo" To: Date: Mon, 29 Mar 2010 21:43:15 -0400 Message-ID: MIME-Version: 1.0 X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 In-Reply-To: <000801cacf95$c6808a70$0901a8c0@lark> Importance: Normal DomainKey-Status: good (testing) X-Spam-Score: 0.9 (/) X-Spam-Report: autolearn=disabled,DNS_FROM_RFC_WHOIS=0.879,UNPARSEABLE_RELAY=0.001 Subject: LF: RE: Re: RE: Re: PF per Meter dependant on wire size? Content-Type: text/plain; charset="iso-8859-1" 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-global-disposition: G x-aol-sid: 3039ac1d40cc4bb1579d7c42 X-AOL-IP: 193.82.116.20 Alan, There is no free lunch. It sounded too simple to be true.. But installation of the system you describe would not be very difficult. Keeping it stable and in one place as you say would be problematic. Then there is matter of trees. Just finished reading about Jim Moritz experiment measuring tree current. My tower has many behind it 2 acres of trees that are 60' high I am afraid now that any current I do manage to get into the air will all be shunted to ground!!!! His experiments were done at 137 so perhaps this loss might be less at 9KHz?? I doubt it though Is there nothing about working this band that is an advantage? :>) Thank you again Alan PauLC W1VLF -----Original Message----- From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Alan Melia Sent: Monday, March 29, 2010 7:16 PM To: rsgb_lf_group@blacksheep.org Subject: LF: Re: RE: Re: PF per Meter dependant on wire size? Hi Paul, there could be a slight problem I suspect. As I understand your set-up, you have a wire (soon to be wires) from the shack to the top of the mast. The bottom of the wires is about 6feet above ground level. The problem that I can see is as follows.......ideally you want the extra capacitance beyond the "radiating part" of the antenna. The radiatingpart being the vertical section in most cases. I think of extra capacitance low in the vertical section as shunting antenna current to ground "before it has passed through all the radiation resistance"....so it is lost power. I believe when I was searching for ideas fro 136kHz the suggestion was to spread the wires at the top of the vertical but cone them in to a single point from 20 or 25 feet above ground level. I finished with a flat-top 6 feet wide but with the vertical wired brought in to a single point. This idea is not quite so easy to install in your system. You may need to dummy or strainer cords to stop the upper section thashing around. There is not a lot of advantage to spreading 4 wires over 9m to speading them over 3m. my "guess" is you will get about 800 to 850pF with 4 wires on a 3m spreader and about 1000pF if you go to a 9m spreader. (dont ask me to explain I knock things over when I wave my arms around :-)) ) Alan G3NYK ----- Original Message ----- From: "Paul A. Cianciolo" To: Sent: Monday, March 29, 2010 11:36 PM Subject: LF: RE: Re: PF per Meter dependant on wire size? > Hi Jim > > Thank you for the formula for calculating "C" of a wire. > Also the information about adding additional wires is valuable. > > There are 2 methods I could try with my 55 meters of wire. > With the use of fiberglass spreaders, multiple wires could be spread apart > at the top of the tower forming a fan of the wires. > With a single point on the shack end where the wires would all would > combine. > > Probably better would be to support 4 wires equally spaced on a fiber glass > poles 9 meters long on both the tower end and the shack end. > > This seems too easy Jim, there must be a point of diminishing returns. > > Knowing that the wire is 55 meters long, and 1 wire measures at 340 pf would > you hazard a guess as to 4 wires 1 meter apart each the value of "C" > > Do you think 700 pf is achievable? > > Thank you for reading > > PaulC > W1VLF > > > > > -----Original Message----- > From: owner-rsgb_lf_group@blacksheep.org > [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of James Moritz > Sent: Sunday, March 28, 2010 4:09 PM > To: rsgb_lf_group@blacksheep.org > Subject: LF: Re: PF per Meter dependant on wire size? > > > Dear Paul, LF Group, > > One formula for C per unit length: > > C = 24/Log(4H/d) picofarads/m , H= height, m, d = diameter, m > > So the capacitance depends on the logarithm of the ratio of height over wire > diameter, which only varies a little for a large change in diameter, e.g for > 1mm wire at 10m high = 5.2pF/m, 10mm diameter wire at 10m high 6.7pF/m. > Actually this formula only applies to an infinitely long, uniform, > horizontal, straight wire. In practice, the presence of ends, downleads, > things on the ground, insulation on the wire, etc. etc. will all have an > effect, and are difficult to calculate, so 6pF/m is usually as good an > estimate as you are likely to get. > > Adding multiple wires will increase capacitance. If the wires are many > metres apart (spacing large compared to height), you can multiply the > capacitance by the number of wires. But usually, the wires are more closely > spaced, and there is less increase in capacitance. The figures I have to > hand are for two 1mm wires 100mm apart, C is higher by 39% compared to a > single wire, 1m apart and C is 68% higher. > > Cheers, Jim Moritz > 73 de M0BMU > > ----- Original Message ----- > From: "Paul A. Cianciolo" > To: > Sent: Sunday, March 28, 2010 8:24 PM > Subject: LF: PF per Meter dependant on wire size? > > > > Hello, > > > > I see from previous posts that a number of aprox 6 PF what size wire is > > this for? > > > > Increasing wire size should in "C" as should several conductors in > > parallel > > spaced a few feet apart. > > > > PauLC > > > > W1VLF > > > > > > > > > > >