Return-Path: Received: from rly-dc06.mx.aol.com (rly-dc06.mail.aol.com [172.19.136.35]) by air-dc04.mail.aol.com (v123.4) with ESMTP id MAILINDC042-b2b4a09675e3ce; Tue, 12 May 2009 08:11:19 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-dc06.mx.aol.com (v123.4) with ESMTP id MAILRELAYINDC067-b2b4a09675e3ce; Tue, 12 May 2009 08:11:13 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1M3qnr-0002fz-Jv for rs_out_1@blacksheep.org; Tue, 12 May 2009 13:09:47 +0100 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1M3qnr-0002fq-5c for rsgb_lf_group@blacksheep.org; Tue, 12 May 2009 13:09:47 +0100 Received: from ttsmtp-3.cpwnetworks.com ([62.24.128.244] helo=ttsmtp.cpwnetworks.com) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1M3qnp-00035x-1d for rsgb_lf_group@blacksheep.org; Tue, 12 May 2009 13:09:47 +0100 X-Path: TalkTalk-smtp X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AqsEADQECUpZ8PlN/2dsb2JhbACEUMd4hAIF Received: from unknown (HELO mal769a60aa920) ([89.240.249.77]) by ttsmtp.cpwnetworks.com with SMTP; 12 May 2009 13:09:39 +0100 Message-ID: <007401c9d2fa$863a6280$0301a8c0@mal769a60aa920> From: "mal hamilton" To: References: <4A01AEA0.1030308@btconnect.com>, <003801c9cfed$3754c170$0301a8c0@mal769a60aa920> <4A094F88.31094.2E46CD4@mike.dennison.ntlworld.com> Date: Tue, 12 May 2009 13:09:37 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: Re: Re: 500kHz Portable Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-AOL-IP: 193.82.116.20 You are certainly NO EXPERT at amateur radio never mind LF/MF and especially antennas. I have worked the world on LF/MF using Inv L antennas with the far end just above ground , and in normal CW mode. Some time ago it was Comics, elevated lemonade bottles as coil formers, thought an AR88D was a diversity fly catcher. What is coming next? The diversity UMBRELLA!!!! My current MF antenna is a full 1/4 wave inv L, 100 ft high and performs well but for some this might be difficult, therefore use what you can get on your property and let the far end tilt down if necessary. G3KEV ----- Original Message ----- From: "Mike Dennison" To: Sent: Tuesday, May 12, 2009 10:29 AM Subject: Re: LF: Re: Re: 500kHz Portable >> You do not need 2 masts for an inv L or T antenna. >> The so called horizontal wire(s) can slope down and the far end tied >> to a bush or tree, or a stake in the ground via an insulator, as far >> away as possible from the vert section, the longer the better. Keep it >> simple. mal/g3kev > > This is quite wrong. Any slope downwards will reduce the effective > height of a Marconi. Since ERP is a function of the square of the > effective height this is extremely important. An umbrella is far > preferable to an inverted-L in a single mast situation because a > large amount of capacitance to ground can be achieved without much > reduction of effective height. > > Based on my experience of LF portable (both on 73 and 136kHz), my > advice is to make very sure that the remote ends of a Marconi are > very well insulated as they carry large voltages. Keep well away from > wet trees. This is not just a safety issue; any voltage leaked is > power lost. > > Mike, G3XDV > ========== > > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.325 / Virus Database: 270.12.25/2109 - Release Date: 05/11/09 16:14:00