Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mb01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 3855B38000081; Sun, 11 Mar 2012 08:30:09 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1S6htf-0000m7-2I for rs_out_1@blacksheep.org; Sun, 11 Mar 2012 12:29:11 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1S6hte-0000ly-Ik for rsgb_lf_group@blacksheep.org; Sun, 11 Mar 2012 12:29:10 +0000 Received: from imr-db02.mx.aol.com ([205.188.91.96]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1S6htb-0000LH-UG for rsgb_lf_group@blacksheep.org; Sun, 11 Mar 2012 12:29:10 +0000 Received: from mtaout-mb06.r1000.mx.aol.com (mtaout-mb06.r1000.mx.aol.com [172.29.41.70]) by imr-db02.mx.aol.com (8.14.1/8.14.1) with ESMTP id q2BCT5gW024961 for ; Sun, 11 Mar 2012 08:29:05 -0400 Received: from White (nrbg-4d0747b3.pool.mediaWays.net [77.7.71.179]) by mtaout-mb06.r1000.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id C9F86E0000BE for ; Sun, 11 Mar 2012 08:29:04 -0400 (EDT) Message-ID: <3011499AB7FD4BBA8C1C0E232306CA1C@White> From: "Markus Vester" To: References: <4F5BD6FD.7080709@iup.uni-heidelberg.de> Date: Sun, 11 Mar 2012 13:29:03 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 12.0.1606 X-MimeOLE: Produced By Microsoft MimeOLE V12.0.1606 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20110426; t=1331468945; bh=0r1ah4cGS8el7/QRgXK1Bff9GsMZlJyU1s/mKnf3asg=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=xZSzZKI/LCH4ilj8zr8ItiJ9gdSvLJ8pnzv1eoX0w/Vso63mKCx/d+eh0V+ebKlBH lTQlV4yFyBrPexloQiPOjjFc9d/UtA+lfk4aSgxzdoyctu1f7G7UtYY8h2z3wEbUJo yx9er6ajsYOFkN9db4OxelmfA1Plm2pZzNkFCIks= X-AOL-SCOLL-SCORE: 0:2:446142848:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: VLF surprise Content-Type: multipart/alternative; boundary="----=_NextPart_000_000F_01CCFF8A.ED152F20" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,HTML_MESSAGE, MISSING_OUTLOOK_NAME 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: 0:2:479835040:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d017.1 ; domain : mx.aol.com DKIM : pass x-aol-sid: 3039ac1d60154f5c9ad14eb1 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Dies ist eine mehrteilige Nachricht im MIME-Format. ------=_NextPart_000_000F_01CCFF8A.ED152F20 Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable Hi Stefan, LF, thanks for sharing this, fascinating indeed! The uploads to the web = apparently froze somtime during the night. Good thing about this is that = the "slow MSK" pic still shows some spectacular colour fading effects on = DHO. Regarding SNR, I also found it hard to get low noise from any loops = located near buildings, as magnetic fields from cables and appliances = are not well contained inside. Perhaps the best solution would be = combined RDF, mode using E-field for brightness (and SNR), and the loops = only as an auxiliary colour channel. This also resolves the 180=B0 = ambiguity. You will need to make an audio 90=B0 phase-difference network = to combine the two loops, eg. by scaling one of the well-known opamp = designs to our frequency range. A common difficulty is the tight phase = tolerance for SSB generation, but it will be much less stringent for an = RDF application.=20 Best 73, Markus (DF6NM) From: Stefan Sch=E4fer=20 Sent: Saturday, March 10, 2012 11:34 PM To: rsgb_lf_group@blacksheep.org=20 Cc: Paul ; Mike Smith=20 Subject: LF: VLF surprise VLF, I just build an arrangement of 2 orthogonal delta loops with a=20 circumference of 10m. They are not resonated and there is still no=20 preamp in use, so they are directly connected to the soundcard. They are made out of CAT5 STP cable, so it is a shielded loop with 8 = turns. Now it is possible to run SpecLab in the Colour Direction Finder mode. Tonite i will be silent on LF just to see how the wideband windows look=20 on VLF. That is a new dimension for me, like switching from black-white=20 TV to colour TV ;-) Sensitivity is about 15 dB down to the E field grabber on the building.=20 This loop is 7m above ground but on the ground of the 2nd floor of that=20 building. Room for improvements. Anyway it is most interesting to see=20 the different colours of DHO38. See = http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html 73, Stefan/DK7FC ------=_NextPart_000_000F_01CCFF8A.ED152F20 Content-Type: text/html; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable
Hi Stefan, LF,
 
thanks for sharing this, fascinating = indeed! =20 The uploads to the web apparently = froze somtime=20 during the night. Good thing about this is that the "slow MSK" = pic=20 still shows some spectacular colour fading effects on = DHO.
 
Regarding SNR, I also found it hard to = get low=20 noise from any loops located near buildings,=20 as magnetic fields from cables and = appliances are not=20 well contained inside. Perhaps the best solution would be combined = RDF,=20 mode using E-field for brightness (and SNR), and the loops only as an=20 auxiliary colour channel. This also resolves the 180=B0=20 ambiguity. You will need to make an audio 90=B0=20 phase-difference network to combine the two loops, eg. by scaling = one of=20 the well-known opamp designs to our frequency range. = A common=20 difficulty is the tight phase tolerance for SSB generation, = but=20 it will be much less stringent for an RDF=20 application. 
 
 
Best 73,
Markus (DF6NM)
 

From: Stefan = Sch=E4fer
Sent: Saturday, March 10, 2012 11:34 PM
Cc: Paul ; Mike=20 Smith
Subject: LF: VLF surprise

VLF,

I just build an arrangement of 2 = orthogonal=20 delta loops with a
circumference of 10m. They are not resonated and = there is=20 still no
preamp in use, so they are directly connected to the=20 soundcard.
They are made out of CAT5 STP cable, so it is a shielded = loop with=20 8 turns.

Now it is possible to run SpecLab in the Colour = Direction Finder=20 mode.

Tonite i will be silent on LF just to see how the wideband = windows=20 look
on VLF. That is a new dimension for me, like switching from = black-white=20
TV to colour TV ;-)

Sensitivity is about 15 dB down to the E = field=20 grabber on the building.
This loop is 7m above ground but on the = ground of=20 the 2nd floor of that
building. Room for improvements. Anyway it is = most=20 interesting to see
the different colours of DHO38.

See http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.ht= ml

73,=20 Stefan/DK7FC

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