Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dh02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 63A1038000117; Tue, 16 Aug 2011 12:30:22 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QtMW5-0003Td-Hu for rs_out_1@blacksheep.org; Tue, 16 Aug 2011 17:29:25 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QtMW5-0003TU-6L for rsgb_lf_group@blacksheep.org; Tue, 16 Aug 2011 17:29:25 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QtMW4-0000PM-PI for rsgb_lf_group@blacksheep.org; Tue, 16 Aug 2011 17:29:25 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id p7GGTNEL009295 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 16 Aug 2011 18:29:24 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id p7GGTNfe025093 for ; Tue, 16 Aug 2011 18:29:23 +0200 Message-ID: <4E4A9A1F.2060600@iup.uni-heidelberg.de> Date: Tue, 16 Aug 2011 18:26:07 +0200 From: =?UTF-8?B?U3RlZmFuIFNjaMOkZmVy?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <68BE37BD69E54DEE89CEBA8E30E9B94E@PcMinto> <4E47FFE9.10100@iup.uni-heidelberg.de> <3ED8E5422F1F45DBB8186E9D9870AD63@PcMinto> <4E480E02.9020706@iup.uni-heidelberg.de> <938BF599006244949F6CDDB5BA91F347@PcMinto> <4E482FBD.7030402@freenet.de> <4E484183.9090805@iup.uni-heidelberg.de> <4E494A57.90105@freenet.de> <4E4956DA.1060201@iup.uni-heidelberg.de> <4E49643E.5090708@freenet.de> <4E496FF9.4040608@iup.uni-heidelberg.de> <0A4ED65EC3B244A3BD0DAD6ACFF43793@JimPC> <4E4A5597.4070709@iup.uni-heidelberg.de> <3746D901368F4C139E414F9110153EEE@JimPC> In-Reply-To: <3746D901368F4C139E414F9110153EEE@JimPC> X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: Ferrite RX antennas Content-Type: text/plain; charset=UTF-8; format=flowed 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: 0:2:396602272:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d41164e4a9b1d3e2d X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Hi Jim, Am 16.08.2011 17:54, schrieb James Moritz: > >> I took an analog homemade VFO to generate a sine wave at 137 kHz, 20 >> mVp at 50 Ohm, measured with an oscilloscope. Then i added a 43 dB >> attenuator between RX (which has a 50 Ohm input) and VFO. > > So, assuming the oscilloscope also had a 50ohm input termination, the > input to the receiver would be (20mV - 43dB) = 142uV, actually 3dB > more than the 100uV figure you mention. I did the measurement with a high-Z probe while the VFO was connected to the attenuator (50 Ohm type), using a BNC T-piece. The 20 mV is the peak level (thus mVp ;-) ) while the mentioned 100 uV is rms. 73, Stefan/DK7FC