Return-Path: Received: (qmail 298 invoked from network); 13 Jul 2001 14:12:34 -0000 Received: from unknown (HELO warrior-inbound.servers.plus.net) (212.159.14.227) by excalibur.plus.net with SMTP; 13 Jul 2001 14:12:34 -0000 Received: (qmail 15257 invoked from network); 13 Jul 2001 14:11:33 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior with SMTP; 13 Jul 2001 14:11:33 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 15L3aU-0002jj-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 13 Jul 2001 15:06:34 +0100 Content-Transfer-Encoding: 8bit Received: from relay.dera.gov.uk ([192.5.29.49]) by post.thorcom.com with smtp (Exim 3.16 #2) id 15L3aS-0002je-00 for rsgb_lf_group@blacksheep.org; Fri, 13 Jul 2001 15:06:32 +0100 Received: (qmail 17692 invoked from network); 13 Jul 2001 15:04:13 +0100 Received: from trtnmail.dera.gov.uk (146.80.9.56) by relay.dera.gov.uk with SMTP; 13 Jul 2001 15:04:13 +0100 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 1882 invoked from network); 13 Jul 2001 15:07:46 +0100 Received: (ofmipd 192.5.29.90); 13 Jul 2001 14:07:24 -0000 Received: by bob.dera.gov.uk; (8.8.8/1.3/10May95) id PAA22285; Fri, 13 Jul 2001 15:11:18 +0100 (BST) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: (qmail 11792 invoked from network); 13 Jul 2001 14:57:57 -0000 Received: from gauntlet.mail.dera.gov.uk (172.16.9.10) by baton.dera.gov.uk with SMTP; 13 Jul 2001 14:57:57 -0000 Received: by gauntlet.mail.dera.gov.uk; id OAA21582; Fri, 13 Jul 2001 14:47:06 GMT Received: from unknown(10.71.64.31) by gauntlet.mail.dera.gov.uk via smap (3.2) id xma021565; Fri, 13 Jul 01 14:46:40 GMT Received: from mailex.dera.gov.uk (unverified) by mailguard.dera.gov.uk (Content Technologies SMTPRS 4.1.5) with SMTP id for ; Fri, 13 Jul 2001 15:04:34 +0100 Received: (qmail 12446 invoked from network); 13 Jul 2001 13:54:41 +0100 Received: from softdnserror (HELO cchecker.dstl.gov.uk) (192.168.248.52) by mailex.dstl.gov.uk with SMTP; 13 Jul 2001 12:54:41 -0000 Received: from FRN-MAIL-R3 (unverified) by cchecker.dstl.gov.uk (Content Technologies SMTPRS 4.1.2) with ESMTP id for ; Fri, 13 Jul 2001 13:54:44 +0100 Received: by FRN-MAIL-R3 with Internet Mail Service (5.5.2650.21) id <356X22WF>; Fri, 13 Jul 2001 15:04:18 +0100 Date: 13 Jul 2001 15:04:19 +0100 Message-ID: <7D653C9C42F5D411A27C00508BF8803D55C552@pdw-mail-r1.dstl.gov.uk> From: "Andrew Talbot" To: rsgb_lf_group@blacksheep.org Subject: LF: RE: Fw: Near field of 9kHz antenna MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset=iso-8859-1; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Looks very much like like 1/R^3 fall off - just as the equations predict. I seem to recall the magnetic field falls off even faster - 1/R^6 sound familiar. Looks as if allocations at 9kHz could be a headache. If below 9kHz is not allocated by ITU then administrations cannot issue licences / NoVs. But any radiation there are indeed radio transmission, so should be licensed. Does anyone have a spare 1.2H inductor, rated for 100kV at 9kHz :-) Andy G4JNT -----Original Message----- From: Dick Rollema [mailto:d.w.rollema@freeler.nl] Sent: 2001-07-13 14:09 To: LF-Group Subject: LF: Fw: Near field of 9kHz antenna >To All from PA0SE >Computer program Antenna Optimizer by K6STI permits to calculate the near field of an antenna up to a distance of 2km. I did so for a vertical for >9kHz. I had to make it 180m high before computation was possible -- The Information contained in this E-Mail and any subsequent correspondence is private and is intended solely for the intended recipient(s). For those other than the recipient any disclosure, copying, distribution, or any action taken or omitted to be taken in reliance on such information is prohibited and may be unlawful.