X-GM-THRID: 1214434992783322238 X-Gmail-Labels: rsgb lf X-Gmail-Received: 7b54f5d95bc1777517371e3a2e25ce4305809b07 Delivered-To: daveyxm@gmail.com Received: by 10.64.250.20 with SMTP id x20cs907067qbh; Wed, 13 Sep 2006 16:48:35 -0700 (PDT) Received: by 10.48.202.19 with SMTP id z19mr11467971nff; Wed, 13 Sep 2006 16:48:34 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.gmail.com with ESMTP id x24si18154967nfb.2006.09.13.16.48.32; Wed, 13 Sep 2006 16:48:34 -0700 (PDT) Received-SPF: neutral (gmail.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) DomainKey-Status: bad (test mode) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1GNeR9-0007zN-CQ for rs_out_1@blacksheep.org; Thu, 14 Sep 2006 00:46:35 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1GNeR9-0007zE-0P for rsgb_lf_group@blacksheep.org; Thu, 14 Sep 2006 00:46:35 +0100 Received: from smtp814.mail.ird.yahoo.com ([217.146.188.74]) by relay1.thorcom.net with smtp (Exim 4.62) (envelope-from ) id 1GNeR5-0007rE-32 for rsgb_lf_group@blacksheep.org; Thu, 14 Sep 2006 00:46:34 +0100 Received: (qmail 45118 invoked from network); 13 Sep 2006 23:46:25 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btinternet.com; h=Received:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=X97E1K7dP2TvsZZ1S2/C9AvUdQJr+mrzaIxixHZ9/MBeFWqvZucr1HbVq7PecK3ntF6+vcckyalR0VAbmO5G0WpiZeusT76Ye85dTwqgjJngpp1ct0LC8L1mXFSuyhCerjW9fAHxKjZLyi96zF2b+H8ndOZ0oW8LdpEaydHFQ/c= ; Received: from unknown (HELO lark) (alan.melia@btinternet.com@213.122.75.63 with login) by smtp814.mail.ird.yahoo.com with SMTP; 13 Sep 2006 23:46:24 -0000 Message-ID: <003401c6d78e$d3dc5d00$0300a8c0@lark> From: "Alan Melia" To: References: <000801c6d757$0c6af2e0$60be3b3e@fujitsu> Date: Thu, 14 Sep 2006 00:46:22 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2615.200 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2615.200 X-Spam-Score: -0.5 (/) X-Spam-Report: autolearn=disabled,AWL=-0.489 Subject: LF: Re: antenna calculation..help needed Content-Type: text/plain; charset="iso-8859-1" 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=1.1 required=5.0 tests=MAILTO_TO_SPAM_ADDR 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 Status: O X-Status: X-Keywords: X-UID: 4571 Dick, You could use a quarter wave length of 75 ohm coax in series from the base, as a matching transformer....allowing for velocity factor of course Cheers de Alan G3NYK ----- Original Message ----- From: Dick To: Sent: 13 September 2006 18:06 Subject: LF: antenna calculation..help needed Hello all, It's off topic, but as I can't find it on the net I'll ask it here. I want to modify an old 27MHz CB antenna to an quarter wave vertical for 30m (10.14MHz) Diameter is tapering from 26 to 15mm. Question: what length should it have? I suppose 0.25 wavelength x 0.96 or so... Sofar not a big problem, but as I will use 36 radials direct on the ground, it's radiation resitance will be around 36Ohm. To match this to 50Ohm I can use a series capacitor, but what value this should be?? Who can tell me? 73 Dick, pa4vhf