Return-Path: Received: (qmail 14713 invoked from network); 4 Aug 2003 14:04:24 -0000 Received: from netmail01.services.quay.plus.net (212.159.14.219) by netmail00.services.quay.plus.net with SMTP; 4 Aug 2003 14:04:24 -0000 Content-Transfer-Encoding: 8bit Received: (qmail 16950 invoked by uid 10001); 4 Aug 2003 14:04:23 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from post.thorcom.com (193.82.116.70) by netmail01.services.quay.plus.net with SMTP; 4 Aug 2003 14:04:23 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.14) id 19jfsv-0004SB-Jo for rsgb_lf_group-outgoing@blacksheep.org; Mon, 04 Aug 2003 15:00:25 +0100 Received: from [212.125.75.12] (helo=mail4.messagelabs.com) by post.thorcom.com with smtp (Exim 4.14) id 19jfsq-0004S2-GH for rsgb_lf_group@blacksheep.org; Mon, 04 Aug 2003 15:00:20 +0100 X-VirusChecked: Checked X-Env-Sender: William.Ashlock@bocedwards.com X-Msg-Ref: server-14.tower-4.messagelabs.com!1060005613!1012587 X-StarScan-Version: 5.0.7; banners=bocedwards.com,-,- Received: (qmail 32476 invoked from network); 4 Aug 2003 14:00:13 -0000 Received: from ukfw1.ge.boc.com (193.131.2.157) by server-14.tower-4.messagelabs.com with SMTP; 4 Aug 2003 14:00:13 -0000 Received: from exc_wil04.edwards.boc.com ([162.118.144.226]) by exc_cra03.edwards.boc.com with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2653.13) id PTKGF56J; Mon, 4 Aug 2003 15:06:03 +0100 Received: by EXC_WIL04 with Internet Mail Service (5.5.2653.19) id <33WG59A6>; Mon, 4 Aug 2003 10:00:11 -0400 Message-ID: From: "Ashlock,William" To: rsgb_lf_group@blacksheep.org Date: Mon, 4 Aug 2003 10:00:09 -0400 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) Subject: RE: LF: RE: Re: 500m drums of coax dipole Content-Type: text/plain; charset=iso-8859-1; format=flowed X-Spam-Status: No, hits=0.0 required=5.0tests=noneversion=2.55 X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rsgb_lf_group-outgoing@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false David, > Yes, yes I agree. But there is something interesting about seeing a self resonant antenna at these frequencies. Also I remember a QEX article a while ago that detailed underground dipoles used by USAF for emergency communication with aircraft. The efficiencies were all less than 5 % but that's much better than our -30dB etc. The USAF antennas were suspended in tubes so the antenna had a few inches of 'air' before meeting the soil. I remember seeing a Buried Antenna' article some time back! I'll see if I can find this. BTW, when you resonate your antenna don't neglect the the reduction in length due to the change in 'velocity factor' because of the proximity of the ground. This may reduce the length considerably (and save some work/money). Bill A _____________________________________________________________________ This e-mail has been scanned for viruses by MCI's Internet Managed Scanning Services - powered by MessageLabs. For further information visit http://www.mci.com