Return-Path: X-Spam-DCC: paranoid 1290; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: * X-Spam-Status: No, score=1.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_HOTMAIL_RCVD,HTML_10_20,HTML_MESSAGE autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u19FmPDM027611 for ; Tue, 9 Feb 2016 16:48:25 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1aTAQ0-000388-Ni for rs_out_1@blacksheep.org; Tue, 09 Feb 2016 15:41:32 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1aTAQ0-00037s-8Y for rsgb_lf_group@blacksheep.org; Tue, 09 Feb 2016 15:41:32 +0000 Received: from blu004-omc1s34.hotmail.com ([65.55.116.45]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-SHA384:256) (Exim 4.86) (envelope-from ) id 1aTAOy-0001MI-9h for rsgb_lf_group@blacksheep.org; Tue, 09 Feb 2016 15:41:31 +0000 Received: from BLU185-W48 ([65.55.116.8]) by BLU004-OMC1S34.hotmail.com over TLS secured channel with Microsoft SMTPSVC(7.5.7601.23008); Tue, 9 Feb 2016 07:40:14 -0800 X-TMN: [dkvrpqJ6IKi0QyYUL8uK18IzlRWn32Q8] X-Originating-Email: [hellozerohellozero@hotmail.com] Message-ID: From: Laurence KL7 L To: "rsgb_lf_group@blacksheep.org" Date: Tue, 9 Feb 2016 06:40:13 -0900 Importance: Normal In-Reply-To: <56B9CC5E.27362.3B9702@roelof.ndb.demon.nl> References: , <013701d162a4$4c6aa0b0$e53fe210$@comcast.net>, ,<56B9CC5E.27362.3B9702@roelof.ndb.demon.nl> MIME-Version: 1.0 X-OriginalArrivalTime: 09 Feb 2016 15:40:14.0248 (UTC) FILETIME=[2B1F9A80:01D16350] X-Scan-Signature: c95b9a52470b89d54f2ef38e923e05cb Content-Type: multipart/alternative; boundary="_ba5c4b19-70b7-4785-a3d5-59031fa2fcfa_" Subject: LF: VLF and isolating transformers - More 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: RO X-Status: X-Keywords: X-UID: 6763 --_ba5c4b19-70b7-4785-a3d5-59031fa2fcfa_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks Roelof - Im the same - Ive tried countless revisions of isolations a= nd earth points and probably close to optimum within local site conditions = (overhead power to my left about 300ft away) =20 The large standard 1ohm 1mH 10m sided VLF loop is the same design we used = for VLF research in Antarctica/North Pole on the transglobe expedition back= in 79/82=2C but for the life of me I couldn't recall the transformer detai= ls=3B but having been given a prod by Jim/Edgar/Luis et al Ive figured out= what it was using some of the pictures of the AWESOME receiver and when it= gets light Ill try this new winding ratio and thicker primary wire. =20 We ended up not being able to use the VLF receiver up in the Arctic as we w= ere located in small huts just near the end of the runway at CFS Alert in 8= 1/82 and the runway lighting noise was awful - the VLF array was moved onto= fast sea ice but still the noise was too bad for whistlers etc. =20 Cheers Laurence =20 > From: roelof@ndb.demon.nl > To: rsgb_lf_group@blacksheep.org > Date: Tue=2C 9 Feb 2016 12:24:14 +0100 > Subject: Re: LF: RE: Vlf ot Penguins and awesomes - More >=20 > Hello Laurence=2C >=20 > For your interest. >=20 > I do not know how you couple the E-probe to your receiver. > For years=2C I have been using a rf - isolating transformer to=20 > separate antenna and receiver ground. >=20 > This is a home made transmission line transformer=2C consisting of 11=20 > bifilar turns on a small high mu toroid (AL=3D8300). The inductance is=20 > 1.2 mH. The measured -3dB bandwidth in a 50 ohm system covers 4 kHz=20 > - 200 MHz. >=20 > It appeared that the isolation was not perfect=2C due to the=20 > inter-winding capacitance. I have made a new transformer on the same=20 > core with two windings of each tree turns. The windings are opposite=20 > each other on the core. The bandwidth is now 45 kHz - 50 MHz. The=20 > loss is 1.3 dB. >=20 > Despite the raise in the lower -3dB point=2C reception at VLF is much=20 > improved due to lower noise ingress. See attachment. > The screen runs from 1 kHz - 13 kHz. At the right hand the dashes =20 > from the Russian Alpha system can be seen. The white band is with > common ground. Harmonics of the 50 Hz mains can be easily spotted.=20 > In reality the picture will be better=2Cas the sensitivity of the=20 > PERSEUS drops considerable below 10 kHz. >=20 > The level of interference on 380 kHz caused by a plasma TV in the=20 > neighbourhood is also much reduced. >=20 > Like you=2C I found that local noise on a loop is much worse. >=20 > 73=2C > Roelof=2C pa0rdt=20 >=20 >=20 = --_ba5c4b19-70b7-4785-a3d5-59031fa2fcfa_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks Roelof - Im the same - Iv= e tried countless revisions of isolations and earth points and probably clo= se =3Bto optimum within local =3Bsite conditions (overhead power to= my left about 300ft away)
 =3B
The large standard 1ohm 1mH 10m s= ided =3B =3BVLF loop is the same design we used for VLF research in= Antarctica/North =3BPole on the transglobe expedition back in 79/82=2C=  =3Bbut for the life of me I couldn't recall the transformer details=3B= but having been given a prod by Jim/Edgar/Luis et al =3B Ive figured o= ut what it was using some of the pictures of the AWESOME receiver and when = it gets light Ill try this new =3Bwinding =3Bratio and thicker prim= ary wire.
 =3B
We ended up not being able to use the VLF receiver= up in the Arctic as we were located in small huts =3Bjust near the end= of the runway at CFS Alert in 81/82 and the runway lighting noise was awfu= l - the VLF array was moved onto fast sea ice but still the =3Bnoise wa= s too bad for whistlers etc.
 =3B
Cheers
Laurence
 =3B<= BR>
>=3B From: roelof@ndb.demon.nl
>=3B To: rsgb_lf_group@blacks= heep.org
>=3B Date: Tue=2C 9 Feb 2016 12:24:14 +0100
>=3B Subject= : Re: LF: RE: Vlf ot Penguins and awesomes - More
>=3B
>=3B Hell= o Laurence=2C
>=3B
>=3B For your interest.
>=3B
>=3B = I do not know how you couple the E-probe to your receiver.
>=3B For ye= ars=2C I have been using a rf - isolating transformer to
>=3B separat= e antenna and receiver ground.
>=3B
>=3B This is a home made tra= nsmission line transformer=2C consisting of 11
>=3B bifilar turns on = a small high mu toroid (AL=3D8300). The inductance is
>=3B 1.2 mH. Th= e measured -3dB bandwidth in a 50 ohm system covers 4 kHz
>=3B - 200 = MHz.
>=3B
>=3B It appeared that the isolation was not perfect=2C= due to the
>=3B inter-winding capacitance. I have made a new transfo= rmer on the same
>=3B core with two windings of each tree turns. The = windings are opposite
>=3B each other on the core. The bandwidth is n= ow 45 kHz - 50 MHz. The
>=3B loss is 1.3 dB.
>=3B
>=3B Des= pite the raise in the lower -3dB point=2C reception at VLF is much
>= =3B improved due to lower noise ingress. See attachment.
>=3B The scre= en runs from 1 kHz - 13 kHz. At the right hand the dashes
>=3B from = the Russian Alpha system can be seen. The white band is with
>=3B comm= on ground. Harmonics of the 50 Hz mains can be easily spotted.
>=3B I= n reality the picture will be better=2Cas the sensitivity of the
>=3B= PERSEUS drops considerable below 10 kHz.
>=3B
>=3B The level of= interference on 380 kHz caused by a plasma TV in the
>=3B neighbourh= ood is also much reduced.
>=3B
>=3B Like you=2C I found that loc= al noise on a loop is much worse.
>=3B
>=3B 73=2C
>=3B Roel= of=2C pa0rdt
>=3B
>=3B
= --_ba5c4b19-70b7-4785-a3d5-59031fa2fcfa_--