Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-md02.r1000.mx.aol.com (Internet Inbound) with ESMTP id C6D79380000AC; Mon, 28 May 2012 17:59:47 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SZ7wz-0000MR-R2 for rs_out_1@blacksheep.org; Mon, 28 May 2012 22:58:05 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SZ7wy-0000MI-I7 for rsgb_lf_group@blacksheep.org; Mon, 28 May 2012 22:58:04 +0100 Received: from nm13.bullet.mail.ird.yahoo.com ([77.238.189.66]) by relay1.thorcom.net with smtp (Exim 4.77) (envelope-from ) id 1SZ7wv-0006pE-AB for rsgb_lf_group@blacksheep.org; Mon, 28 May 2012 22:58:03 +0100 Received: from [77.238.189.53] by nm13.bullet.mail.ird.yahoo.com with NNFMP; 28 May 2012 21:57:59 -0000 Received: from [212.82.108.247] by tm6.bullet.mail.ird.yahoo.com with NNFMP; 28 May 2012 21:57:59 -0000 Received: from [127.0.0.1] by omp1012.mail.ird.yahoo.com with NNFMP; 28 May 2012 21:57:59 -0000 X-DKIM-Result: Domain=yahoo.co.uk Result=Good and Known Domain X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 963632.10950.bm@omp1012.mail.ird.yahoo.com Received: (qmail 67609 invoked by uid 60001); 28 May 2012 21:57:59 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.co.uk; s=s1024; t=1338242279; bh=98fEUErgkGq9Q0nRNsXpJ43Dn0m9n//XPupEZ/XJSeo=; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=e0R1d9Fp2QbzRRhGCsCAmt0yHVqeglqt2ZD3PbMQlVQd4rpQB0vw5RR5O5dsZC3pA5huywDyO2g8A1e5XgRm626INnGGKCy8zQFu0jZjHy6uj4biKMk/dOb/HtJXsa4vm9TxXdCUALMIVOncddGpeX72LzPzmcbCq6OKMqGmk7c= 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=emMvEqH1hXFc7QmtYaqNgH3mwFn40+06d/uCDwqhb+sEvkHbn8bCZiH1JAecD5dHZxl7wNGOuzVdxbythRPTZ3wdj66kmIB+W5WgZ4hZsSsdhUxgki7eYfaAmwmTFSUmULYGQCb6rLKyANGEE7jpFyK1oqrxwn/evJgHFJh7EMg=; X-YMail-OSG: 5hxL95cVM1lkHH77W2C1uEBHxbHZ7vZHKFwUKC1mKeGl.ah wh812V42.egLthcJWosjjuoj8mkZQFdFhUaBTsyVoHJptr05qCgpUTSUygKB omogNxxccIvF7UayzYbx7_hRLxk2vNuwEkbyfQYQJt9lFn0a8mSzCYl3B2GQ URAnPXbyIsbmj1uJgZaO1FhkLXLGpWtrE2hfZ3DlhUDoWB.rYmVMlUkDmwtJ hMpmJFvjlH_cyZcGGpl3.t17sixV7NXauOJckjLsfnrCoWYmIN07XbpSopvv 5twwPr.B3wRdqaF0GB_G9tPvzmKirpVTYdL2ofQWVl8mxuLidxDjoFC3O9As DnaBbZFCARsuZ5C3DKlTOL3ake5KKfa33ie_8rfBOSdF2M5AOa05GTWX56bQ RwuAEiWjSbq8Ar6gc79R6sr3zP0pI700lbP4byIdaOadJCKSBj9I7cUmpY2o .2UN8ZiPrlj7WRcKhScj0w7wOl5QUx5lWCzg_drx0G2SYWEWtjMqYjAqEAfq Gbjh0ktVNQ26nHkPzkzam2Y_SyWeINDGmenpBu7gEYl486XO5NDZ5PCErA3C f1OuXWRzyK7PRpARxbKeWC0r2LRIrXg7vm96UjeXqp7CF29QVhueYAwz8Hmp iyzgVQxDm30uCBmhl5iM- Received: from [86.163.7.35] by web171602.mail.ir2.yahoo.com via HTTP; Mon, 28 May 2012 22:57:59 BST X-Mailer: YahooMailWebService/0.8.118.349524 References: <4FC39CF3.7020701@legal-medicine.de> <1338226811.63172.YahooMailNeo@web171601.mail.ir2.yahoo.com> <016501cd3d01$453debc0$4001a8c0@lark> Message-ID: <1338242279.43694.YahooMailNeo@web171602.mail.ir2.yahoo.com> Date: Mon, 28 May 2012 22:57:59 +0100 (BST) From: M0FMT To: "rsgb_lf_group@blacksheep.org" In-Reply-To: <016501cd3d01$453debc0$4001a8c0@lark> 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: Sounds good Alan. I don't think I have anything to add. I hope Peter3LP sorts his problems using a twisted pair DC feed through a (modified Coax cable , I like that idea) screen. Oh and I don't like to spend money either so good advice. Working at audio (8Kc/s Dreamers - 20kc/s SAQ / Mil) with an active antenna I could see there may be an issue with the long power feed to the amplifier picking up EMC which may be getting through to the RX (soundcard). The screen to conductor capacity varing owing to screening sheath to conductor spacing altering because of applied cyclic mechanical force did not seem an unlikely cause of microphony. Basically a very long capacitive microphone. However if no mechanical force (air born pressure wave or otherwise) is applied then no microphony should occur. So your explaination is the likely one..... probably. 73 es GL Pete M0FMT IO91UX [...] 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 [77.238.189.66 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: 860e51ceecdf98b32e8eba101d9d472d Subject: Re: LF: VLF/LF-Preamp Content-Type: multipart/alternative; boundary="1507048413-1026860600-1338242279=:43694" 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=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: 0:2:416895264:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m013.1 ; domain : yahoo.co.uk DKIM : fail x-aol-sid: 3039ac1d60564fc3f552481b X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --1507048413-1026860600-1338242279=:43694 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Sounds good=A0Alan.=0A=A0=0AI don't think I have anything to add. I hope Pe= ter3LP sorts his problems using=A0a twisted pair DC feed=A0through a (modif= ied=A0Coax cable , I like that idea) screen.=0A=A0=0AOh and I don't like to= spend money either so good advice.=A0=0A=A0=0AWorking at audio (8Kc/s Drea= mers=A0- 20kc/s SAQ /=A0Mil) with an active antenna I could see there may b= e an issue with the long power feed to the amplifier picking up EMC=A0which= may be=A0getting through to the RX (soundcard). The screen to conductor ca= pacity varing owing to screening sheath to conductor=A0spacing altering bec= ause of=A0 applied cyclic mechanical force did not seem an unlikely cause o= f microphony. Basically a very long capacitive microphone. However if no me= chanical force (air born pressure wave=A0or otherwise) is applied then no m= icrophony should occur. =0A=A0=0ASo your explaination is the likely one....= . probably.=0A=A0=0A73 es GL Pete M0FMT IO91UX=0A=0A=0A____________________= ____________=0A From: Alan Melia =0ATo: rsgb_lf_= group@blacksheep.org =0ASent: Monday, 28 May 2012, 19:18=0ASubject: Re: LF:= VLF/LF-Preamp=0A =0AHi Peter just a quick butt-in...... dont waste money = on noiseless microphone=0Acable! :-)) This is prevent noise on low-level au= dio signal WHEN THE CABLE=0AIS FLEXED AND TWISTED. It has no advantage is t= he cable is not moved. There=0Awhat is called a "tribo-electric effect in c= able which is akin to rubbing a=0Aplastic rod (or an amber rod if you are o= ld or rich enough :-)) ) which a=0Acats pelt. (or possibly silk) The flexin= g of the coax (or STP) generates a=0Astatic charge which varies with moveme= nt so generates an audio=0Anoise/crackle. Use a tightly twisted pair like y= ou suggested and you can=0Aactually pull the centre insulator out of old UR= 67 or RG213 and pull the=0Atwisted pair though that.=A0 Cheaper than solid = plumbing ! I was first shown=0Athat by telephone engineers :-))=0A=0AAlan= =0AG3NYK=0A=0A----- Original Message ----- =0AFrom: "M0FMT" =0ATo: =0ASent: Monday, May 28, 2012 6:40= PM=0ASubject: Re: LF: VLF/LF-Preamp=0A=0A=0AHi Peter=0A=0AIf you are talki= ng about the dc supply cable being both an electromagnetic=0Aantenna but al= so a microphone then I am sure you already know that A/ using=0Aa twisted b= alanced arrangement may cut the first, and B/ spending a load of=0Acash on = a specialist microphone cable by say ATM may cut the second=0Ahttp://www.mt= raudio.com/atmcables.htm ............. They say=0A=0A" The secret of noisel= ess microphone cable is to combat both electromagnetic=0Ainterference and m= echanical=0Avibration (microphony).=A0 ATM uses a twist technique and high = grade lapp=0Ashield=0Ato reject electro-magnetic interference.=A0 The outer= jacket material is=0Achosen=0Afor resilience and pliability but also has v= ibration absorbing=0Aproperties.=A0 Internal cotton fillers further reduce = microphony.=A0 These=0Afeatures=0Acombine to give ATM accurate, noise free = signal path=0Aperformance."=0A=0ABut a more practical approach may be to tw= ist your own wire in a hand drill=0A(like I do) and feed it through a thin = copper pumbing tube then filling the=0Awhole thing with that sealing expand= ing foam (which I don't do). It may=0Awork, never tried it myself. Also loo= k at the screen grounding, have the far=0Aend un-grounded or visa versa.=0A= =0AThinking about it some more I use microphone cable for my Rig to PC=0Aco= nnections stolen from my sons Guitar Kit Its very thick and squashy. That= =0Anever gives any RF or Microphony issues but that may be just luck.=0A=0A= Suggest you migrate to the Yahoo RSGB LF site for a wider discussion group= =0Athere are more informed people there than me.=0A=0AAny way good luck and= let us know how you get on, this cannot be a new issue=0AI am sure.=0A=0A7= 3 es GL Pete M0FMT IO91UX=0A=0A=0A________________________________=0AFrom: = pws =0ATo: "rsgb_lf_group@blacksheep.org" =0ASent: Monday, 28 May 2012, 16:42=0ASubject: LF: VLF/= LF-Preamp=0A=0AHi,=0A=0AAfter all those meta-discussions here's a more seri= ous problem:=0A=0AI'm playing around with a new e-field probe based on the = INA111.=0Ahttp://www.ti.com/product/ina111=0A=0ASchematic: http://www.df3lp= .de/misc/rx/INA111_preamp.png=0A=0AIt's working fine and the local interfer= ences are lower compared to=0Amy old non-balanced design running here on ba= lcony. That was the goal.=0A=0AAmplification is quite enough to drive a M-A= udio audiophile 192 soundcard.=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 the shields of a thin double coaxial line for bringing= up=0Athe supply voltage. The voltage splitter is located at the far end in= side=0Athe small amplifier box.=0A=0AThe problem is that I'm observing to a= lot of interferences/microphonics=0A"from behind" when touching the batter= y located inside the house.=0A=0A???=0A=0APeter, df3lp --1507048413-1026860600-1338242279=:43694 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Sounds good Alan.
 
I don't think I have anything to add. I hope Peter= 3LP sorts his problems using a twisted pair DC feed through a (mo= dified Coax cable , I like that idea) screen.
 
Oh and I don't like to spend money either so good advice. 
 
Working at audio (8Kc/s Dreamers - 20kc/s SAQ /&nbs= p;Mil) with an active antenna I could see there may be an issue with the lo= ng power feed to the amplifier picking up EMC which may be gettin= g through to the RX (soundcard). The screen to conductor capacity varing ow= ing to screening sheath to conductor spacing altering because of = applied cyclic mechanical force did not seem an unlikely cause of micropho= ny. Basically a very long capacitive microphone. However if no mechanical force (air born pressure wave or otherwise) is applied the= n no microphony should occur.
 
So your explainat= ion is the likely one..... probably.
 
73 es GL Pe= te M0FMT IO91UX
From: Alan Melia <alan.melia@btinternet.co= m>
To: rsgb_lf_grou= p@blacksheep.org
Sent: Monday, 28 May 2012, 19:18
Subj= ect: Re: LF: VLF/LF-Preamp

Hi Peter just a quick butt-in....= .. dont waste money on noiseless microphone
cable! :-)) This is prevent = noise on low-level audio signal WHEN THE CABLE
IS FLEXED AND TWISTED. It= has no advantage is the cable is not moved. There
what is called a "tri= bo-electric effect in cable which is akin to rubbing a
plastic rod (or a= n amber rod if you are old or rich enough :-)) ) which a
cats pelt. (or = possibly silk) The flexing of the coax (or STP) generates a
static charg= e which varies with movement so generates an audio
noise/crackle. Use a = tightly twisted pair like you suggested and you can
actually pull the ce= ntre insulator out of old UR67 or RG213 and pull the
twisted pair though= that.  Cheaper than solid plumbing ! I was first shown
that by tel= ephone engineers :-))

Alan
G3NYK

----- Original Message --= ---
From: "M0FMT" <m0fmt@yahoo.co.uk>
To: <= rsgb_lf_group@blacksheep.org>
Sent: Monday, = May 28, 2012 6:40 PM
Subject: Re: LF: VLF/LF-Preamp


Hi Peter<= br>
If you are talking about the dc supply cable being both an electroma= gnetic
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/ spen= ding 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 electromag= netic
interference and mechanical
vibration (microphony).  ATM u= ses a twist technique and high grade lapp
shield
to reject electro-magnetic interference.  The outer jacket material is
chose= n
for resilience and pliability but also has vibration absorbing
prop= erties.  Internal cotton fillers further reduce microphony.  Thes= e
features
combine to give ATM accurate, noise free signal path
pe= rformance."

But a more practical approach may be to twist your own w= ire in a hand drill
(like I do) and feed it through a thin copper pumbin= g tube then filling the
whole thing with that sealing expanding foam (wh= ich I don't do). It may
work, never tried it myself. Also look at the sc= reen grounding, have the far
end un-grounded or visa versa.

Think= ing about it some more I use microphone cable for my Rig to PC
connectio= ns 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.

Sugges= t 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 su= re.

73 es GL Pete M0FMT IO91UX


__________________________= ______
From: pws <pws@legal-medicine.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-discus= sions here's a more serious problem:

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

Schema= tic: h= ttp://www.df3lp.de/misc/rx/INA111_preamp.png

It's working fine a= nd the local interferences are lower compared to
my old non-balanced des= ign running here on balcony. That was the goal.

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

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

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

???
=
Peter, df3lp




--1507048413-1026860600-1338242279=:43694--