Return-Path: Received: (qmail 21801 invoked from network); 31 Jan 2002 22:39:37 -0000 Received: from unknown (HELO warrior.services.quay.plus.net) (212.159.14.227) by excalibur.plus.net with SMTP; 31 Jan 2002 22:39:37 -0000 Received: (qmail 19070 invoked from network); 31 Jan 2002 22:39:34 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior.services.quay.plus.net with SMTP; 31 Jan 2002 22:39:34 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16WPpF-00017T-00 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 31 Jan 2002 22:37:01 +0000 Received: from lycee.ns.uk.easynet.net ([195.40.1.37]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16WPpD-00017O-00 for rsgb_lf_group@blacksheep.org; Thu, 31 Jan 2002 22:36:59 +0000 Received: from erica (tnt-3-253.easynet.co.uk [195.40.202.253]) by lycee.ns.uk.easynet.net (Postfix) with SMTP id B7B11A2F3 for ; Thu, 31 Jan 2002 22:36:01 +0000 (GMT) Message-ID: <000401c1aaa8$325455e0$fdca28c3@erica> From: "g3ldo" To: rsgb_lf_group@blacksheep.org References: <3.0.1.16.20020130114238.31479a9a@pb623250.kuleuven.be> Subject: Re: LF: Tesla Coil as an antenna Date: Thu, 31 Jan 2002 22:38:54 -0000 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 5.50.4522.1200 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 have not experimented in a while with my partially built tesla coil, > >> but has anyone used their Tesla coil as an antenna for ELF or other Freqs? > I assume that a typical tesla coil is a rather short and fat structure. I > am not sure that in this case the magnetic field can be ignored, compared > to the electric field. And since a Tesla coil has rather small dimensions - > compared to other LF transmitting antennas - I'm afraid that it will have a > very low efficiency. > BUT ... since you have the Tesla coil available I would certainly recommend > to do some tests (that's what all the fun is about). Over two years ago I reported on the Tesla coil as a radiator. I was operating at radio station at Amberley Museum and was told that there could be some QRM because of a Tesla group who had set up at the Electricity Hall. I did not experience any QRM so after my operating stint I drove my car near to where some of the larger coils were being tested. I was told by the group that the frequencies in used depended on the size of the coil with the large ones on about 130kHz and the one very big one on 70kHz. These coils produced some very spectacular displays. I had my old 707 rig with a converter with me and used a 2m length of wire as an antenna. The rig was located about 100m from the coils. I tuned around the LF bands while some of these monsters were being fired up and heard - nothing! The receiver was working because I could hear the lager commercial stations without difficulty. It could be that all the energy was being dissipated the spark - but I would have expected to receive something. All these big coils were using the rotary spark gap method of firing the primary coils - a spectacular display in themselves. Regards, Peter, G3LDO e-mail Web