Return-Path: Received: from mtain-me05.r1000.mx.aol.com (mtain-me05.r1000.mx.aol.com [172.29.96.141]) by air-dc06.mail.aol.com (v129.4) with ESMTP id MAILINDC064-86a44d0a7f0a241; Thu, 16 Dec 2010 16:05:14 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-me05.r1000.mx.aol.com (Internet Inbound) with ESMTP id CD44A38000181; Thu, 16 Dec 2010 16:05:12 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PTKzw-00013y-P7 for rs_out_1@blacksheep.org; Thu, 16 Dec 2010 21:04:24 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PTKzw-00013p-8R for rsgb_lf_group@blacksheep.org; Thu, 16 Dec 2010 21:04:24 +0000 Received: from nm19-vm0.bullet.mail.ac4.yahoo.com ([98.139.53.212]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1PTKzv-00082d-Dj for rsgb_lf_group@blacksheep.org; Thu, 16 Dec 2010 21:04:24 +0000 Received: from [98.139.52.195] by nm19.bullet.mail.ac4.yahoo.com with NNFMP; 16 Dec 2010 21:04:17 -0000 Received: from [98.139.52.178] by tm8.bullet.mail.ac4.yahoo.com with NNFMP; 16 Dec 2010 21:04:17 -0000 Received: from [127.0.0.1] by omp1061.mail.ac4.yahoo.com with NNFMP; 16 Dec 2010 21:04:17 -0000 X-Yahoo-Newman-Id: 90618.55338.bm@omp1061.mail.ac4.yahoo.com Received: (qmail 7051 invoked from network); 16 Dec 2010 21:04:16 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btinternet.com; h=DKIM-Signature:Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=V7B+LBxGhUM0zXkOlSAZvCSF5JvXIPJIr5KD0CCWKTon6dfX3YnxpbiGo/TGLOin+wotX1g1kSqXbwbnke/xlYK8tPf0ZQ5F4KxqMlvmtWSxt/DM2TN9mOE0GVFsWTueyJLBxODhB3kX/fuGeQ1GIAqkWPVEgzOdM1SV592MNrE= ; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btinternet.com; s=s1024; t=1292533456; bh=E6YXPxW37KW2h9nPP9/JxXndqPXs+vEddOQrUYOU/hk=; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=A2M+I+yzgb+hdrLdGK7AtgrI0D7V9vJECkOFyPB950Ti91z+r40cXkhxQLXDNpr9prRSOxs0sgEIW0iTq/JBaXCJrWvtWKWYaiO1WMlVs/UCyaGipdfmQy2yCV5XTDhNFtkdMzQQwAuxWPkSZkaPU6emTc9V7mFgvTJss0ofBwo= Received: from lindavideo (ken.h.wright@86.162.64.127 with login) by smtp130.mail.mud.yahoo.com with SMTP; 16 Dec 2010 13:04:16 -0800 PST X-Yahoo-SMTP: 9Y6mUHuswBAgnrOsukIiNdFDf95uy_Dz34nY1hlg2liKgYD952sjbg-- X-YMail-OSG: 91IzykwVM1kppLHJjNAI8Yn5PjCVGo_rDBz9NHmvCqIeHyR mhmWOueQb9MnsO4lnM54U6pqpB_2Pzb0uUwS7bMqi_W7kd7q5fiQODm_emBw 9CV2MaTuNXC2iHjEZM3ESjENECBU.lyoVMajtf8Dz.PL1860UWX9ow9p2PEU mKxLMgBaHx81A8cEgyoKFB43yKufISglvuMRVRZSHIS1HtxhuV_Mxd8_03UD ynXCrO_pW3YPCmrfVpx1DKjEVLHADDcM5dxxXDChXEH4dqRo71ZUUbcIuP3R nC0K7LcraABSoxGUWEEmIBrSzNZe0ORj0Hxnzqthj8uC0FYcg53xv.jXVtoF u7a8ZlzdCNGOWGscrV_NN4YZf1HUpKnVYGy4FQXmh0v4cjMk_ X-Yahoo-Newman-Property: ymail-3 Message-ID: <061B7DFBCF9048E9A7F715A530E1EE96@lindavideo> From: "Ken" To: References: <005201cb9d61$8bdf3200$0201a8c0@Clemens04> Date: Thu, 16 Dec 2010 21:04:13 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5994 DomainKey-Status: good (testing) X-Spam-Score: 3.4 (+++) X-Spam-Report: autolearn=disabled,FORGED_MUA_OUTLOOK=3.36,HTML_MESSAGE=0.001,UNPARSEABLE_RELAY=0.001 Subject: LF: Re: Re: Sound Card mic Impedance Content-Type: multipart/alternative; boundary="----=_NextPart_000_0066_01CB9D64.CAD30AB0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.1 required=5.0 tests=FORGED_MUA_OUTLOOK,HTML_40_50, HTML_MESSAGE 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-AUTHENTICATION: mail_rly_antispam_dkim-d288.2 ; domain : btinternet.com DKIM : fail x-aol-sid: 3039ac1d608d4d0a7f087a38 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_0066_01CB9D64.CAD30AB0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Clements. Are you sure, shunting a 50 ohm resistor with 4k ohms reduces it down= to 49.38 ohms or am I missing something?. 73. Ken M0KHW=20 ----- Original Message -----=20 From: Clemens Paul=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, December 16, 2010 8:40 PM Subject: LF: Re: Sound Card mic Impedance Ken, >I am doing a Low Pass Filter to use with Winrad, F1, 20kHz, F2, 30= kHz, 100kHz -80 dB (theoretical) with a >characteristic impedance of= 50 ohms, with this high input impedance I can locate the filter very= close to the sound >card mic input and terminate the filter output wi= th a 50 ohm resistor. Assuming 4kOhm input impedance of the soundcard this will cause a mi= smatch loss of around 13dB (95% loss) which may or may not cause concern dependi= ng of the signal level of your antenna. 73 Clemens DL4RAJ ----- Original Message -----=20 From: Ken=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, December 16, 2010 9:06 PM Subject: LF: Sound Card mic Impedance Thank you all LFs. Thank you for all the info that you sent me, it looks they can be= anything from 4k ohms upwards, this is ok for me, I am doing a Low= Pass Filter to use with Winrad, F1, 20kHz, F2, 30 kHz, 100kHz -80 dB= (theoretical) with a characteristic impedance of 50 ohms, with this= high input impedance I can locate the filter very close to the sound= card mic input and terminate the filter output with a 50 ohm resistor= . Hopefully this will eliminate the BC intermod I was experiencing whe= n trying to receive Chris G3XIZ the other day. 73 Ken M0KHW I091TV=20 ------=_NextPart_000_0066_01CB9D64.CAD30AB0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Clements.
Are you sure, shunting a 50 ohm resis= tor with 4k=20 ohms reduces it down to 49.38 ohms or am I missing something?.<= /DIV>
73.
Ken
M0KHW 
----- Original Message -----
Sent: Thursday, December 16,= 2010 8:40=20 PM
Subject: LF: Re: Sound Card= mic=20 Impedance

Ken,
 
>I am doing  a Low Pass Fil= ter to use=20 with Winrad, F1, 20kHz, F2, 30 kHz, 100kHz -80 dB (theoretical) = ;with a=20 >characteristic impedance of 50 ohms, with this high input impeda= nce I=20 can locate the filter very close to the sound >card mic inpu= t and=20 terminate the filter output with a 50 ohm resistor.
 
Assuming 4kOhm input impedance of= the soundcard=20 this will cause a mismatch loss
of around 13dB (95% loss) which may= or=20 may not cause concern depending of the signal=20 level of
your antenna.
 
 
73
Clemens
DL4RAJ
----- Original Message -----
From:=20 Ken
Sent: Thursday, December 16= , 2010 9:06=20 PM
Subject: LF: Sound Card mic= =20 Impedance

Thank you all LFs.
Thank you for all the info that= you sent me, it=20 looks they can be anything from 4k ohms upwards, this is ok for me= , I am=20 doing  a Low Pass Filter to use with Winrad, F1, 20kHz, F2,= 30 kHz,=20 100kHz -80 dB (theoretical) with a characteristic impedance= of 50 ohms,=20 with this high input impedance I can locate the filter= very close=20 to the sound card mic input and terminate the filter output with= a 50 ohm=20 resistor. Hopefully this will eliminate the BC intermod I was= =20 experiencing when trying to receive Chris G3XIZ the other day.
 
73
Ken
M0KHW  =20 I091TV 
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