X-GM-THRID: 1227361996873346512 X-Gmail-Labels: rsgb lf Delivered-To: daveyxm@gmail.com Received: by 10.70.58.13 with SMTP id g13cs138351wxa; Sat, 3 Feb 2007 03:53:33 -0800 (PST) Received: by 10.65.159.2 with SMTP id l2mr826864qbo.1170503613455; Sat, 03 Feb 2007 03:53:33 -0800 (PST) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.google.com with ESMTP id q15si7615860qbq.2007.02.03.03.53.31; Sat, 03 Feb 2007 03:53:33 -0800 (PST) Received-SPF: neutral (google.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) DomainKey-Status: bad (test mode) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1HDJOO-00060C-DK for rs_out_1@blacksheep.org; Sat, 03 Feb 2007 11:49:16 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1HDJON-000603-Vv for rsgb_lf_group@blacksheep.org; Sat, 03 Feb 2007 11:49:16 +0000 Received: from smtp809.mail.ird.yahoo.com ([217.146.188.69]) by relay3.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1HDJOK-0003W9-0U for rsgb_lf_group@blacksheep.org; Sat, 03 Feb 2007 11:49:15 +0000 Received: (qmail 32529 invoked from network); 3 Feb 2007 11:49:06 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btopenworld.com; h=Received:X-YMail-OSG:Received:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=NOwq8tBjCv0OlP/BRYdhk/9WpKkS6cgG8VIcDLOw4T1PRp4fTvtskwIgK3wy5w9qBTxu/LnfzMBRHd3uHwmPRqlhX/WNghNb6194lgYwkl0NHvP5MDnuWxR//dIeM7G2rftFfFbxwir6VXr26WqjWbjs7gBn1Tr668Yue1ty5Ww= ; Received: from unknown (HELO w4o8m9) (james.moritz@btopenworld.com@81.131.49.136 with login) by smtp809.mail.ird.yahoo.com with SMTP; 3 Feb 2007 11:49:05 -0000 X-YMail-OSG: g7JcZW8VM1m1QJb4xsWr919kjsYARZwzuYkWDMv9J0vp9GMDw7rRICFgmBaQr6MKsVL8UpsIG4pq6esj2sjQrnin9A9KSBfWZjC7zSCLD5c6wnylpd9yW5jIVOudZUgOFkv5APKUWX_e Received: from 127.0.0.1 (AVG SMTP 7.5.432 [268.17.21/665]); Sat, 03 Feb 2007 11:44:00 +0000 Message-ID: <000d01c74788$98c944c0$88318351@w4o8m9> From: "James Moritz" To: References: <014b01c7471a$33278be0$0b01a8c0@server> Date: Sat, 3 Feb 2007 11:44:00 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: LF: Re: Ladderline C per foot? 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 Status: O X-Status: X-Keywords: X-UID: 3192 Dear JB, LF Group, The capacitance (per metre) of a transmission line is: C = 1/(Zo.Vf.c) Where Zo is characteristic impedance in ohms, Vf is the velocity factor, which basically depends on the insulation, and c is the speed of light (3 x 10^8 m/s). For 450ohm ladder line, velocity factor seems to be around 0.9, and the above formula works out to 8.23pF/m, or as Peter says, 2.5pF per foot. Cheers, Jim Moritz 73 de M0BMU ----- Original Message ----- From: "J. B. Weazle McCreath" To: "LowFER at LW Cafe" Cc: Sent: Friday, February 02, 2007 10:33 PM Subject: LF: Ladderline C per foot? > Hello Lowfers & LFers, > > Does anyone on the lists happen to know the approximate > capacity per foot of 450 ohm windowed poly ladderline? > > 73, J.B., VE3EAR - VE3WZL > Solar and wind powered > Lowfer " EAR" 188.830 > EN93dr > > http://www.hurontel.on.ca/~weazle > > > >