Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_PASS,T_HK_NAME_DR autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: EATSERVER: mailn 1166; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v5PHde1m002002 for ; Sun, 25 Jun 2017 19:39:42 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1dPBR8-0002wf-Vb for rs_out_1@blacksheep.org; Sun, 25 Jun 2017 18:35:02 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1dPBR8-0002wW-2G for rsgb_lf_group@blacksheep.org; Sun, 25 Jun 2017 18:35:02 +0100 Received: from mailout02.t-online.de ([194.25.134.17]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1dPBR5-0006Jh-8z for rsgb_lf_group@blacksheep.org; Sun, 25 Jun 2017 18:35:00 +0100 Received: from fwd31.aul.t-online.de (fwd31.aul.t-online.de [172.20.26.136]) by mailout02.t-online.de (Postfix) with SMTP id 93C9F41A2F1B for ; Sun, 25 Jun 2017 19:34:57 +0200 (CEST) Received: from [192.168.1.6] (XpRPr6ZcwhUBD34dkIZqehu8GTzdDIJ3I8vcbHBTbZx-NoNWzymm8dW1dveLC+9Q5y@[31.213.199.110]) by fwd31.t-online.de with (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384 encrypted) esmtp id 1dPBR0-1PlLmK0; Sun, 25 Jun 2017 19:34:54 +0200 To: rsgb_lf_group@blacksheep.org References: <1649946984.20170624173724@gmail.com> From: "Dr. Wolf Ostwald" Message-ID: <14ef5335-0580-7887-edd1-431f99c882ff@t-online.de> Date: Sun, 25 Jun 2017 19:34:54 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <1649946984.20170624173724@gmail.com> X-ID: XpRPr6ZcwhUBD34dkIZqehu8GTzdDIJ3I8vcbHBTbZx-NoNWzymm8dW1dveLC+9Q5y X-TOI-MSGID: 78684758-250e-41c7-aa20-e55487483282 X-Scan-Signature: 7aa9ad08848e488e22e0ff1d71f4ef1d Subject: Re: LF: Insulating a Versatower from ground Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit 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-Scanned-By: MIMEDefang 2.75 Status: RO X-Status: X-Keywords: X-UID: 12104 hi Chris ! when we started to do 136 in the late 90s, i had a 100 ft tower with umbrella type tophat sitting on 1.5 inch Teflon blocks. 8000 pounds of steel winched with hydraulic tools onto it. loaded with a series adjustable coil. Worked OK from Italy to Scotland with audible CW. But after first enthusiastic experiments, the number of workable stations declined and now i have a 6 el for 15m on it. I have one of the Versatowers here to suspend another yagi, and it has the extension piece in it. I doubt whether it is possible to use Teflon under constant mechanical stress, it will do a cold flow and come loose. >From the electrical point of view, u dont need the large conducting surface of the steel tower at that impedance. I would rather run a vertical wire some ten feet away parallel to the tower up to Your toop-hat loop. of course suspended at the top by a beefy insulator of sufficient length. Create Your own ground screen with the feed say ten feet away from the tower base. In short, You are feeding at a high impedance point, therefor the thick tower is of no extra benefit as an RF- conductor. 73 de wolf df2py