Return-Path: Received: (qmail 19867 invoked from network); 15 May 2002 03:59:09 -0000 Content-Transfer-Encoding: 8bit X-Priority: 3 Received: from unknown (HELO marstons.services.quay.plus.net) (212.159.14.223) by excalibur.plus.net with SMTP; 15 May 2002 03:59:09 -0000 X-MSMail-Priority: Normal Received: (qmail 15601 invoked by uid 10001); 15 May 2002 04:03:06 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from unknown (HELO post.thorcom.com) (193.82.116.70) by marstons.services.quay.plus.net with SMTP; 15 May 2002 04:03:06 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 177poO-0002d1-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 15 May 2002 04:50:48 +0100 Received: from astral.infomsk.ru ([212.164.44.2] helo=astral.omskcity.com) by post.thorcom.com with esmtp (Exim 3.33 #2) id 177poM-0002cv-00 for rsgb_lf_group@blacksheep.org; Wed, 15 May 2002 04:50:47 +0100 Received: from fitec.omskcity.com (mu06.dialup2.infomsk.ru [212.164.44.118]) by astral.omskcity.com (8.9.3/8.9.3) with SMTP id KAA3ce1da4b1f09 for ; Wed, 15 May 2002 10:47:23 +0700 (OSS) Date: Wed, 15 May 2002 11:27:44 +0000 (GMT) From: "Alexander S. Yurkov" To: rsgb_lf_group@blacksheep.org Subject: RE: LF: Ground loss In-reply-to: <3.0.1.16.20020514131621.08dfed86@pb623250.kuleuven.be> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi, Rik. On Tue, 14 May 2002, Rik Strobbe wrote: > > >If Lcp=0 this means that ground wire only touch to the ground in infinity > >small point. So R should be infinity large. If there is no conterpoint > >Lcp is a ground rod length. > I agree about Lcp is really 0. > But if I take Lcp = 0.2m (short ground rod only), Lant= 30m , C = 150pF (Xc > = 7800 Ohm) and a = 0.01 then R = (Lant/Lcp)*a*Xc = 11700 Ohm. I believe > that this value is far too high, a more realistic value would be a few > hundred Ohm. When I derive the formula I assumed wires capacitance 5 pF/meter If wire is VERY short (0.2 meters) it's not true. For such a short wire there is about 20 pF/meter. If do some corrections resistance for ground rode of 0.2 meter is about 3000 Ohm, not 11700 Ohm. Are You sure real resistance is few hundred Ohm WHEN THERE IS NO LONG WIRE to connect TX to such a short ground rod? Does You do such experiment? 73 de RA9MB/Alex http://www.qsl.net/ra9mb