Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dd04.r1000.mx.aol.com (Internet Inbound) with ESMTP id A28F0380000B1; Mon, 28 May 2012 13:41:45 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SZ3vW-0007cM-2z for rs_out_1@blacksheep.org; Mon, 28 May 2012 18:40:18 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SZ3vV-0007cD-4j for rsgb_lf_group@blacksheep.org; Mon, 28 May 2012 18:40:17 +0100 Received: from nm17-vm0.bullet.mail.ird.yahoo.com ([77.238.189.214]) by relay1.thorcom.net with smtp (Exim 4.77) (envelope-from ) id 1SZ3vR-0005qv-Mx for rsgb_lf_group@blacksheep.org; Mon, 28 May 2012 18:40:16 +0100 Received: from [77.238.189.232] by nm17.bullet.mail.ird.yahoo.com with NNFMP; 28 May 2012 17:40:11 -0000 Received: from [212.82.108.238] by tm13.bullet.mail.ird.yahoo.com with NNFMP; 28 May 2012 17:40:11 -0000 Received: from [127.0.0.1] by omp1003.mail.ird.yahoo.com with NNFMP; 28 May 2012 17:40:11 -0000 X-DKIM-Result: Domain=yahoo.co.uk Result=Good and Known Domain X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 502765.27141.bm@omp1003.mail.ird.yahoo.com Received: (qmail 63721 invoked by uid 60001); 28 May 2012 17:40:11 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.co.uk; s=s1024; t=1338226811; bh=ycGwAT+bvSQp9K7QwovORv3kUplBovVm7R0t8XK954s=; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=wX2OgZ8AbhYSwI/IJjJlBXb43HlK7oh6PmgBdBmZ8qqW8mIBj6a/M+lmT+tjDfUnoyYvl9yM/h0YI7yj6w2iHbegFPWmXoOAgWjzHFUf2HkiNqMeK5ti0iI63V/OLcAWPdpxSgIF0HkrXNR1Dsk5TtoKvDImJNQanuEQ1lOrumA= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.co.uk; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=38Ip1FhdI6QakuX41m64+qUZYnYoPBq08BZ1z9uLlGi9MudLcOftIOjrkEGZIlKBCAz8S81Ko+s9HX7FYM8woecu108TQ+OMTDTvJhxsr319F6cMiGqZFPphl2eJuYOnJGZV2CO6LAk5rqhZJU9iq2YcKNAzrZY3lXqxjhQgj50=; X-YMail-OSG: m68iLzQVM1mt.Pt3yNyFqC7bt0nQ1pU6m2.VGAOdNyIGNKS I3Zy9e4EdIncH.2FDqmq5fEA6LTLPuI_K_5ZDQRw00JXPkQmwsbI3vME5ggI vwHPLTFHZ1tKAFNBExHMnJ75Ll8bYz93XpvZvycONtvaf0AXmIfz3QKbwMR3 RoUQ2fXiN1cd0VRfp0fnb13AHUyshr7qFxnCqrXg36FALB1ujK4wMFBgKNH9 1y_6RhxpX0xJ7Xn89Uzi7a8373hCiO6iSof7fU6Gji9jYhArQ3qo4L11Jj5. MqC7b0HTKKG5910Rkjrf8VinJDzRv2LBhvphVuu7t.KwDR80Z.mV620aSIb2 zjbx8te7n9mYoYlKLMCmWMiHKYl4UjkYJUj6gvkUFAUjeQS.FmV12QCSdTLZ JYJlmDWHE7FF0P0wFukpR2qUJ6LF8nSDwrqjK.Dz9ActHd_wxZzSsOSb6f56 dGc8bjmRMEOLF2YJF8czOKPEx0K4m5sP10cXCx5icUOO3_L8EPKEjJqmd7X. IsdxP.ZemObHLAnHIhz8gskvfwmgQQxe0TxP3aAP.F9rblBkFAlu23prZUSc 5qOqKN2TGCqE9PGs_hWf.DcOHJ.lrda0oeBgMfdj2Y0kiNzXsiAKPPR6ONPn 8qiijmELMFyJa5ermKvDckqM- Received: from [86.128.227.228] by web171601.mail.ir2.yahoo.com via HTTP; Mon, 28 May 2012 18:40:11 BST X-Mailer: YahooMailWebService/0.8.118.349524 References: <4FC39CF3.7020701@legal-medicine.de> Message-ID: <1338226811.63172.YahooMailNeo@web171601.mail.ir2.yahoo.com> Date: Mon, 28 May 2012 18:40:11 +0100 (BST) From: M0FMT To: "rsgb_lf_group@blacksheep.org" In-Reply-To: <4FC39CF3.7020701@legal-medicine.de> MIME-Version: 1.0 X-Spam-Score: 0.0 (/) 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: Hi Peter If you are talking about the dc supply cable being both an electromagnetic antenna but also a microphone then I am sure you already know that A/ using a twisted balanced arrangement may cut the first, and B/ spending a load of cash on a specialist microphone cable by say ATM may cut the second http://www.mtraudio.com/atmcables.htm They say " The secret of noiseless microphone cable is to combat both electromagnetic interference and mechanical vibration (microphony). ATM uses a twist technique and high grade lapp shield to reject electro-magnetic interference. The outer jacket material is chosen for resilience and pliability but also has vibration absorbing properties. Internal cotton fillers further reduce microphony. These features combine to give ATM accurate, noise free signal path performance." But a more practical approach may be to twist your own wire in a hand drill (like I do) and feed it through a thin copper pumbing tube then filling the whole thing with that sealing expanding foam (which I don't do). It may work, never tried it myself. Also look at the screen grounding, have the far end un-grounded or visa versa. Thinking about it some more I use microphone cable for my Rig to PC connections stolen from my sons Guitar Kit Its very thick and squashy. That never gives any RF or Microphony issues but that may be just luck. Suggest you migrate to the Yahoo RSGB LF site for a wider discussion group there are more informed people there than me. Any way good luck and let us know how you get on, this cannot be a new issue I am sure. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [77.238.189.214 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (m0fmt[at]yahoo.co.uk) 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 85c54099682e8e65d9e25bf804a68673 Subject: Re: LF: VLF/LF-Preamp Content-Type: multipart/alternative; boundary="-1613889061-1031218145-1338226811=:63172" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,HTML_MESSAGE, TO_ADDRESS_EQ_REAL 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: 0:2:387015648:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d012.1 ; domain : yahoo.co.uk DKIM : fail x-aol-sid: 3039ac1d40904fc3b8d87e79 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ---1613889061-1031218145-1338226811=:63172 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Hi Peter=0A=A0=0AIf you are talking about the dc supply cable being both an= electromagnetic antenna but also a microphone then I am sure you already k= now that A/ using a twisted balanced arrangement may cut the first,=A0 and = B/=A0spending a load of cash on a specialist microphone cable by=A0say ATM= =A0may cut the second=A0=A0http://www.mtraudio.com/atmcables.htm=A0=A0.....= ........ They say=0A=A0=0A"=A0The secret of noiseless microphone cable is t= o combat both electromagnetic interference and mechanical =0Avibration (mic= rophony). ATM uses a twist technique and high grade lapp shield =0Ato reje= ct electro-magnetic interference. The outer jacket material is chosen =0Af= or resilience and pliability but also has vibration absorbing =0Aproperties= . Internal cotton fillers further reduce microphony. These features =0Aco= mbine to give ATM accurate, noise free signal path =0Aperformance."=0A=A0= =0ABut a more practical approach may be to twist your own wire in a hand dr= ill (like I do) and feed it through a thin copper pumbing tube then filling= the whole thing with that sealing expanding foam (which I don't do). It ma= y work, never tried it myself. Also look at the screen grounding, have the = far end un-grounded or visa versa.=0A=A0=0AThinking about it some more I us= e microphone cable for my Rig to PC connections stolen from my sons Guitar = Kit Its very thick and squashy. That never gives any RF or Microphony issue= s but that may=A0be just luck.=0A=A0=0ASuggest you migrate to the Yahoo RSG= B LF site for a wider discussion group there are more informed people there= than me.=0A=A0=A0=0AAny way good luck and let us know how you get on, this= cannot be a new issue I am sure.=0A=0A73 es GL Pete M0FMT IO91UX=0A=0A=0A_= _______________________________=0A From: pws =0ATo: = "rsgb_lf_group@blacksheep.org" =0ASent: Mond= ay, 28 May 2012, 16:42=0ASubject: LF: VLF/LF-Preamp=0A =0AHi,=0A=0AAfter a= ll those meta-discussions here's a more serious problem:=0A=0AI'm playing a= round with a new e-field probe based on the INA111.=0Ahttp://www.ti.com/pro= duct/ina111=0A=0ASchematic: http://www.df3lp.de/misc/rx/INA111_preamp.png= =0A=0AIt's working fine and the local interferences are lower compared to= =0Amy old non-balanced design running here on balcony. That was the goal.= =0A=0AAmplification is quite enough to drive a M-Audio audiophile 192 sound= card.=0AThere's a second transformer (1:4) at the af-inputs. The coupling= =0Acapacitance of those transformers are below 10pF each.=0A=0AI'm using th= e shields of a thin double coaxial line for bringing up=0Athe supply voltag= e. The voltage splitter is located at the far end inside the small amplifie= r box.=0A=0AThe problem is that I'm observing to a lot of interferences/mic= rophonics=0A"from behind" when touching the battery located inside the hous= e.=0A=0A???=0A=0APeter, df3lp ---1613889061-1031218145-1338226811=:63172 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Hi Peter
=
 
If y= ou are talking about the dc supply cable being both an electr= omagnetic antenna but also a microphone then I am sure you already know tha= t A/ using a twisted balanced arrangement may cut the first,  and B/ spending a load of cash on = a specialist microphone cable b= y say ATM may cut the second  http://www.mtraudio.com/atmcables.htm &nb= sp;............. They say
 
" The secret of noiseless =0Amicrophone cable is to combat both electromagnetic interference an= d mechanical =0Avibration (microphony). ATM uses a = twist technique and high grade lapp shield =0Ato reject electro-magnetic in= terference. The outer jacket material is chosen =0Afor resilience and plia= bility but also has vibration absorbing =0Aproperties. Internal cotton fil= lers further reduce microphony. These features =0Acombine to give ATM accu= rate, noise free signal path =0Aperformance."
 
But a more practical approach may be to twist your own wire = in a hand drill (like I do) and feed it through a thin copper pumbing tube = then filling the whole thing with that sealing expanding foam (which I don'= t do). It may work, never tried it myself. Also look at the screen groundin= g, have the far end un-grounded or visa versa.
 
Thinking about it some more I use microphone cable for my Rig to = PC connections stolen from my sons Guitar Kit Its very thick and squashy. T= hat never gives any RF or Microphony issues but that may be just luck.=
 <= /div>
Suggest you migrate to the Yahoo RSG= B LF site for a wider discussion group there are more informed people there than me.
  
Any way good luck = and let us know how you get on, this cannot be a new issue I am sure.
73 es GL Pete M0FMT IO91UX
<= b>From: pws <pws@legal-med= icine.de>
To: "rsgb= _lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
Sent: Monday, 28 May 2012, 16:42<= br> Subject: LF: VLF/LF-Preamp

Hi,

After all those meta-discussions here's a more s= erious problem:

I'm playing around with a new e-field probe based on= the INA111.
http://www.ti.com/product/ina111

Schematic: http://www.df3l= p.de/misc/rx/INA111_preamp.png

It's working fine and the local i= nterferences are lower compared to
my old non-balanced design running he= re on balcony. That was the goal.

Amplification is quite enough to d= rive a M-Audio audiophile 192 soundcard.
There's a second transformer (1= :4) at the af-inputs. The coupling
capacitance of those transformers are= below 10pF each.

I'm using the shields of a thin double coaxial lin= e for bringing up
the supply voltage. The voltage splitter is located at the far end inside the small amplifier box.

The problem is that I'm= observing to a lot of interferences/microphonics
"from behind" when tou= ching the battery located inside the house.

???

Peter, df3lp<= br>


 
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