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[195.171.43.25]) by mx.google.com with ESMTP id n1si2946785wib.27.2013.07.13.16.38.54 for ; Sat, 13 Jul 2013 16:38:55 -0700 (PDT) Received-SPF: neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) client-ip=195.171.43.25; Authentication-Results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) smtp.mail=owner-rsgb_lf_group@blacksheep.org Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Uy8vP-0001K2-Rq for rs_out_1@blacksheep.org; Sun, 14 Jul 2013 00:08:23 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Uy8vP-0001Jt-EH for rsgb_lf_group@blacksheep.org; Sun, 14 Jul 2013 00:08:23 +0100 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.77) (envelope-from ) id 1Uy8vN-0008MJ-UB for rsgb_lf_group@blacksheep.org; Sun, 14 Jul 2013 00:08:22 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay2.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id r6DN8Lfs009570 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 14 Jul 2013 01:08:21 +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 r6DN8Koi026802 for ; Sun, 14 Jul 2013 01:08:21 +0200 Message-ID: <51E1DDDF.3020904@iup.uni-heidelberg.de> Date: Sun, 14 Jul 2013 01:08:15 +0200 From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= 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: <51D498BD.3050007@iup.uni-heidelberg.de> <005b01ce798a$b0476600$6d01a8c0@DELL4> <20130706131640.GG5246@cs.utwente.nl> <7D6B8CBB38964C9C82487F5D0F3648FC@FMVXD1232> <20130707203537.GA30691@cs.utwente.nl> <51DA00C8.6000600@iup.uni-heidelberg.de> <51DA0212.8020808@iup.uni-heidelberg.de> <51DA03CE.6020508@iup.uni-heidelberg.de> <51DA1680.6030602@iup.uni-heidelberg.de> <51DB6CB3.2080708@iup.uni-heidelberg.de> <001601ce7c95$f235b360$6401a8c0@JAYDELL> <51DBFF7D.9050807@iup.uni-heidelberg.de> <51DC58E9.5030005@iup.uni-heidelberg.de> <51DF1D06.8020208@iup.uni-heidelberg.de> <51DF43E7.8080300@iup.uni-heidelberg.de> <51E147E2.8080302@iup.uni-heidelberg.de> <002701ce7ff5$714bc830$53e35890$@nifty.com> In-Reply-To: <002701ce7ff5$714bc830$53e35890$@nifty.com> X-Spam-Score: -2.3 (--) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hello Hideho, Thank you. I hope to continue tomorrow or so. I have prepared a list of experiments that i want to do :-) Am 13.07.2013 20:18, schrieb Hideho YAMAMURA: > [...] > Last year, I made a Mini-Dipole with an instrumentation amplifier AD8429 set > at Av=10 (+20dB), > which worked fine, and is in current use. > The dipole elements are aluminum L shape angles, 50cm long each. > I noticed that adding common-mode chokes, LPF on the coax, isolation > transformer to the RX > gave no improvement of signal to noise ratio, > but on the Mini-Whip they slightly did. > I interpret this that the mini-DP is more immune to coax induced noise. > It depends on the grounding situation. If the whip is grounded at the top of the pole and the pole is connected to a clean RF earth and the coax is connected to a noisy shack earth, then the common mode chokes will probably help. But if the whip is only grounded by the coax in the shack, there will be no difference, at least no significant. And the coupling capacity between the windings of an isolation transformer can easily reach the order of magnitude of the probe, i.e. a few pF.... [...] Content analysis details: (-2.3 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [129.206.210.211 listed in list.dnswl.org] -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: 2e2f7cbbe9f38dd7bf3fac4fc012e6fc Subject: Re: LF: Re: MiniWhip antenna, fiber optic TEST SIGNALS NEEDED on 630m WSPR Content-Type: text/plain; charset=ISO-8859-1; 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 Status: O X-Status: X-Keywords: X-UID: 2835 Hello Hideho, Thank you. I hope to continue tomorrow or so. I have prepared a list of experiments that i want to do :-) Am 13.07.2013 20:18, schrieb Hideho YAMAMURA: > [...] > Last year, I made a Mini-Dipole with an instrumentation amplifier AD8429 set > at Av=10 (+20dB), > which worked fine, and is in current use. > The dipole elements are aluminum L shape angles, 50cm long each. > I noticed that adding common-mode chokes, LPF on the coax, isolation > transformer to the RX > gave no improvement of signal to noise ratio, > but on the Mini-Whip they slightly did. > I interpret this that the mini-DP is more immune to coax induced noise. > It depends on the grounding situation. If the whip is grounded at the top of the pole and the pole is connected to a clean RF earth and the coax is connected to a noisy shack earth, then the common mode chokes will probably help. But if the whip is only grounded by the coax in the shack, there will be no difference, at least no significant. And the coupling capacity between the windings of an isolation transformer can easily reach the order of magnitude of the probe, i.e. a few pF.... 73, Stefan/DK7FC