Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dh06.r1000.mx.aol.com (Internet Inbound) with ESMTP id E0C3638000106; Wed, 12 Oct 2011 11:14:51 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1RE0VH-0003X5-8U for rs_out_1@blacksheep.org; Wed, 12 Oct 2011 16:13:55 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1RE0VG-0003Ww-QY for rsgb_lf_group@blacksheep.org; Wed, 12 Oct 2011 16:13:54 +0100 Received: from smtp-out12.han.skanova.net ([195.67.226.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1RE0VE-0007hJ-48 for rsgb_lf_group@blacksheep.org; Wed, 12 Oct 2011 16:13:54 +0100 Received: from [127.0.0.1] (62.20.250.30) by smtp-out12.han.skanova.net (8.5.133) (authenticated as u33233109) id 4E79D83A0060C98A for rsgb_lf_group@blacksheep.org; Wed, 12 Oct 2011 17:13:45 +0200 Message-ID: <4E95AEAA.3070006@telia.com> Date: Wed, 12 Oct 2011 17:13:46 +0200 From: "Johan H. Bodin" User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:7.0.1) Gecko/20110929 Thunderbird/7.0.1 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <1717990DBBAA415989FB6320953D8754@acer> In-Reply-To: X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: Ballpark L & C values for tuner 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=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-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:410815744:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d411a4e95aeeb3b66 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Yes, I have seen it before. That rule of thumb is near resonance with about 500 ohms of reactance (Xc = -j500.5 and Xl = +j471.2 ohms). If you replace 1 metre with 37 inches, the error will be less than 1 percent :-) For C - 1.0 pF. for every 37 inches of wavelength For L - 0.25 uH for every 37 inches of wavelength 73 Johan SM6LKM ---- John Bruce McCreath wrote 2011-10-12 14:44: > Hi LFers, > > I stumbled upon an interesting tidbit of info yesterday which I'd not seen before. > Regarding ballpark figures for the L and C values required for an AMU, the > following was suggested: > > For C - 1.0 pF. for every metre of wavelength > > For L - 0.25 uH. for every metre of wavelength > > Has anyone here seen this before and/or could you confirm it? > > 73, J.B., VE3EAR > > LowFER Beacon "EAR" > 188.830 kHz. QRSS30 > EN93dr