Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-me01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 601AE38000095; Sun, 11 Mar 2012 09:06:42 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1S6iTF-0001DE-4l for rs_out_1@blacksheep.org; Sun, 11 Mar 2012 13:05:57 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1S6iTE-0001D4-Gj for rsgb_lf_group@blacksheep.org; Sun, 11 Mar 2012 13:05:56 +0000 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1S6iTC-0000af-DF for rsgb_lf_group@blacksheep.org; Sun, 11 Mar 2012 13:05:56 +0000 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay2.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id q2BD5rVW021268 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 11 Mar 2012 14:05:53 +0100 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id q2BD5rlq025534 for ; Sun, 11 Mar 2012 14:05:53 +0100 Message-ID: <4F5CA326.9070604@iup.uni-heidelberg.de> Date: Sun, 11 Mar 2012 14:05:42 +0100 From: =?ISO-8859-15?Q?Stefan_Sch=E4fer?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4F5BD6FD.7080709@iup.uni-heidelberg.de> <3011499AB7FD4BBA8C1C0E232306CA1C@White> In-Reply-To: <3011499AB7FD4BBA8C1C0E232306CA1C@White> X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: VLF surprise Content-Type: multipart/alternative; boundary="------------010305030402050907040303" 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 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: 0:2:475298336:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d60894f5ca362387f X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------010305030402050907040303 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay2.uni-heidelberg.de id q2BD5rVW021268 Hi Markus, Unfortunately the SL instances stopped as i started a remote connection=20 from Darmstadt. Maybe this has to do with the windows remote connection.=20 Also it was not possible to restart the instances then. So i tried=20 Teamviewer and VNC as an alternative remote control tool but somehow it=20 doesn't work. Maybe it has to do with the University-Server, no idea.=20 Never mind. I will be back in Heidelberg on Monday evening and will=20 restart the instances on another PC... Am 11.03.2012 13:29, schrieb Markus Vester: > Hi Stefan, LF, > thanks for sharing this, fascinating indeed! The uploads to the web=20 > apparently froze somtime during the night. Good thing about this=20 > is that the "slow MSK" pic still shows some spectacular colour fading=20 > effects on DHO. Yes these effects are very interesting indeed. Unfortunately we haven't=20 seen how the colours are changing when the terminator crosses the path=20 for a specific transmitter. So i/we have to wait 2 days to see that. Oh yes, of course. All this is not new and someone else has done it=20 before. It's important to say that each time one is announcing something=20 personally new ;-) > Regarding SNR, I also found it hard to get low noise from any loops=20 > located near buildings, as magnetic fields from cables and=20 > appliances are not well contained inside. Yes, a pity. It was just a spontaneous test, yesterday, but now i like=20 these way of displaying the band and want to establish it in my system.=20 Don't want to miss it after some few hours :-) One needs a stereo RX for that configuration but on VLF this is no=20 problem since the soundcard... The screen of the loop is still floating. All ground that i tested have=20 made things worse. I will also try audio decoupling transformers and=20 other stuff in the next days but anyway i think the sensitivity will be=20 quite poor in that location. It would be perfect to have the loop in the=20 forest far away from the city and use a stereo wireless headphone=20 link... I really have to... you know ;-) > Perhaps the best solution would be combined RDF, mode using E-field=20 > for brightness (and SNR), and the loops only as an auxiliary colour=20 > channel. This also resolves the 180=B0 ambiguity. You will need to make= =20 > an audio 90=B0 phase-difference network to combine the two loops, eg.=20 > by scaling one of the well-known opamp designs to our frequency range.=20 > A common difficulty is the tight phase tolerance for SSB generation,=20 > but it will be much less stringent for an RDF application. Yes, that's the plan. The E field antenna is available (the "old"=20 grabber antenna) and probably i can move the loop on the top of the=20 building. I will do a pre test to see if its actually worth to move the=20 loop. The problem is the CPU load which is not available for so many SL=20 instances in stereo mode... I'll see ;-) 73, Stefan/DK7FC > Best 73, > Markus (DF6NM) > > *From:* Stefan Sch=E4fer > *Sent:* Saturday, March 10, 2012 11:34 PM > *To:* rsgb_lf_group@blacksheep.org > *Cc:* Paul ; Mike Smith=20 > > *Subject:* LF: VLF surprise > > VLF, > > I just build an arrangement of 2 orthogonal delta loops with a > circumference of 10m. They are not resonated and there is still no > 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=20 > 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 > on VLF. That is a new dimension for me, like switching from black-white > TV to colour TV ;-) > > Sensitivity is about 15 dB down to the E field grabber on the building. > This loop is 7m above ground but on the ground of the 2nd floor of that > building. Room for improvements. Anyway it is most interesting to see > the different colours of DHO38. > > See http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.ht= ml > > 73, Stefan/DK7FC > --------------010305030402050907040303 Content-Type: text/html; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay2.uni-heidelberg.de id q2BD5rVW021268 Hi Markus,

Unfortunately the SL instances stopped as i started a remote connection from Darmstadt. Maybe this has to do with the windows remote connection. Also it was not possible to restart the instances then. So i tried Teamviewer and VNC as an alternative remote control tool but somehow it doesn't work. Maybe it has to do with the University-Server, no idea. Never mind. I will be back in Heidelberg on Monday evening and will restart the instances on another PC...

Am 11.03.2012 13:29, schrieb Markus Vester:
Hi Stefan, LF,
=A0
thanks for sharing this, fascinati= ng indeed!=A0 The uploads to the web apparently froze somtime during the night. Good thing about this is=A0that the=A0"slow MSK" pic still shows some spectacular=A0colour fadi= ng effects on DHO.
Yes these effects are very interesting indeed. Unfortunately we haven't seen how the colours are changing when the terminator crosses the path for a specific transmitter. So i/we have to wait 2 days to see that.
Oh yes, of course. All this is not new and someone else has done it before. It's important to say that each time one is announcing something personally new ;-)

=A0
Regarding SNR, I also found it har= d to get low noise from any loops located near buildings, as=A0magnetic=A0fields=A0from=A0cables and appliances=A0are not well cont= ained inside.
Yes, a pity. It was just a spontaneous test, yesterday, but now i like these way of displaying the band and want to establish it in my system. Don't want to miss it after some few hours :-)
One needs a stereo RX for that configuration but on VLF this is no problem since the soundcard...
The screen of the loop is still floating. All ground that i tested have made things worse. I will also try audio decoupling transformers and other stuff in the next days but anyway i think the sensitivity will be quite poor in that location. It would be perfect to have the loop in the forest far away from the city and use a stereo wireless headphone link... I really have to... you know ;-)

Perhaps the=A0best solution would= be combined RDF, mode using E-field for brightness (and SNR), and the loops only as an auxiliary=A0colour channel.=A0This=A0also resolves the 1= 80=B0 ambiguity.=A0You will=A0need to=A0make an audio=A090=B0 phase-difference = network to combine the two loops, eg. by=A0scaling one of the=A0well-known opamp designs=A0to our frequency range. A=A0common difficulty is=A0the=A0tight = phase tolerance for SSB generation, but it=A0will be=A0much less stringent=A0fo= r=A0an RDF application.
Yes, that's the plan. The E field antenna is available (the "old" grabber antenna) and probably i can move the loop on the top of the building. I will do a pre test to see if its actually worth to move the loop. The problem is the CPU load which is not available for so many SL instances in stereo mode...

I'll see ;-)

73, Stefan/DK7FC


=A0
=A0
=A0
Best 73,
Markus (DF6NM)
=A0

VLF,

I just build an arrangement of 2 orthogonal delta loops with a
circumference of 10m. They are not resonated and there is still no
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
on VLF. That is a new dimension for me, like switching from black-white
TV to colour TV ;-)

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

See http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.h= tml

73, Stefan/DK7FC

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