Return-Path: Received: (qmail 26497 invoked from network); 19 Jun 2001 18:36:42 -0000 Received: from unknown (HELO warrior-inbound.servers.plus.net) (212.159.14.227) by excalibur.plus.net with SMTP; 19 Jun 2001 18:36:42 -0000 Received: (qmail 21916 invoked from network); 19 Jun 2001 18:36:25 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior with SMTP; 19 Jun 2001 18:36:25 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 15CQGo-0006Cz-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 19 Jun 2001 19:30:34 +0100 Received: from tor-smtp4.attcanada.ca ([207.181.101.72] helo=attcanada.ca) by post.thorcom.com with esmtp (Exim 3.16 #2) id 15CQGj-0006Cu-00 for rsgb_lf_group@blacksheep.org; Tue, 19 Jun 2001 19:30:29 +0100 Received: from david (ham-on54-161.netcom.ca [142.154.69.33]) by attcanada.ca (8.8.7-s-4/8.8.7) with SMTP id OAA09445 for ; Tue, 19 Jun 2001 14:29:46 -0400 (EDT) Message-ID: <001501c0f8e5$640c49a0$6655872c@david> From: "Tenty" To: rsgb_lf_group@blacksheep.org References: <000201c0f8e3$74c7f520$736401d5@default> Subject: LF: Re: Static effects Date: Tue, 19 Jun 2001 18:29:24 +0100 Organization: Holland Data and Wireless MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2462.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: I had this problem when I was still living in the Netherlands and my antenna for HF was on top of a 13 story building.. My very thick coax was running true the living room to the shack and I heard from time to time...tick... tick and my wife didn't know where it was coming from...No storm was audible .. Well it was.... little sparks jumping between the shield and the inner conductor! Also did see sparks jumping between the center of a PL259 connector and the outside ring at other times!.. So be aware! 73, Bob ve3tok / pa0tok ----- Original Message ----- From: "Alan Melia" To: "LF-Group" Sent: June 19, 2001 14:48 PM Subject: LF: Static effects Hi All, I am not too sure about Dick's theory. During a period when electrically charged clouds are passing overhead there are extremely high vertical gradients. Imagine a cloud at 3000m charged to 900kV (a modest amount) .....underneath it there would be a gradient of 300V /m thus a wire at 10m would acquire a charge of 3kV wrt gound (This may be modified by the fact the the cloud will induce an equal and opposite charge in the ground so the field may be 600V/m) Thus even Dick's floating wire will become charged up to about 3kV and a 600pF cap charged to 3kV makes quite a nice flash when shorted. I have certainly seem little sparks bridging from a disconnected aerial wire to earthed metallic trunking and central heating radiators, even when there was no storm audible. This is why TV braid breaker filters have a bleeder resistor installed. Rik's bleeder resistors would do the job nicely. Being a coward, I ensure that if possible, the end of the aerial is outside the house and grounded during a storm. This is probably one time when lossy wet trees around the aerial are a positive benefit !! Cheers de Alan G3NYK Alan.Melia@btinternet.com Cheers de Alan G3NYK