Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id x5BFa79t029751 for ; Tue, 11 Jun 2019 17:36:09 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1haiju-0001Nb-C5 for rs_out_1@blacksheep.org; Tue, 11 Jun 2019 16:31:10 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1haijt-0001NS-Fq for rsgb_lf_group@blacksheep.org; Tue, 11 Jun 2019 16:31:09 +0100 Received: from sonic314-13.consmr.mail.bf2.yahoo.com ([74.6.132.123]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92) (envelope-from ) id 1haijo-00050y-5l for rsgb_lf_group@blacksheep.org; Tue, 11 Jun 2019 16:31:08 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=aol.com; s=a2048; t=1560267062; bh=Tu3S5JMkzu2V2nvwNJjK6ISBUv7AA2LLDfrEJ/jPWH4=; h=Date:From:To:In-Reply-To:References:Subject:From:Subject; b=jDD+EsrMhIzEo8YPkIFO+pTvyMOSTlRDV6hpGscFRu82nv2rGtT9VV9/N9ha1DivUlOBvx99FyjjBw7IayJg9ZE70kB6dE+ymbnUSbJaZ7a1GcKzP4Bk1K0BGS6Oosrjzjh2HVo/9A03q4MtMty4NxQSo9/i6+gUKZfL6QqoyDX5zdEaIkC34lvppb+y1+GrkVAbvJKNqFCUyQPjVZvKDDHsRDhaQe1f2rwr+CpSNefW/YDWR6ioSxFw4pqcww/eR8qrcvQq0LxWC4+0OgnOMLIU8dZmaQAo7hMOifrST+rQ0VWb9Tbixpz+is4Fmdxwa0nIv+ySxj6K9l5y4pg5tA== X-YMail-OSG: GbceNvgVM1kDEvI_tPehPW8EZYqiYQeV5RcqtY1BPa5p1.HDAKfZugh4OudOP8w AFgXCQCuX8Eo_7HIH5c3mxmZgBz4uSMnm2VX9gAat7Sq2csOD_UviJe.G6UESlH1bv0vIQSzq5O6 .au1bts50l6ZA.sgPKWKXAeNE0UsuqlELpFOstVUIrrn.PVpu26aEf4TlafbCpGYRnKs7P5QgU6a 7HgJ0O85wslY.qK8weeUu0kcKurAS7L5HkUf_J9PCF_ROmEqPdsHnuMhZVDAlV_cYTqhQauJM4zh nF.N06Kx0BIdfH_LckUEasB2dzneCgXw5fLYFlIe91zKZ.OLWwfZtUuR8bvElgC7PSIMx04pVXZ8 nI865vKKOUHfgxM1fsRsoX0.0Mi7BY8ToL_WjZvR7m66LrsujL4dCqYXTlC9kBy3mcVYlbrPuEsf tUjoI.VaXCA8OVZbZjqQ4DPhwiAWkZlwPK7uv3lprhemCIMvNnuwn04BVimtLtVwW9uZCcPlwJMS UULeGygSKyKioPmHgUx95qaBQo6f_3KJaX6lVO3dLrMUgPe6riqX5Bgdytm.9kzkHEUfDw.LRNIo rH3CVk.gP0JtD6vh8QSYpvYn0cfEF9AEFq6dPnflyhi44xkiz7U4JlRCNxMLIyZPvDeZhRGQmfBn IZsABJXXubJki7IOxZkQDCRN7oeWAlw2RCnt8uLi4LC2ydWnUN1QZMeMopnru2pkUZnEN.bUBYSR jzyWHpL6P8rWG2prClnDSMnEeuIQ052SOefglEgLQpVJWXpg8ZohFEuitcsyHH1Qknh0lUkVZHRE CNWi1pIvd6YBEL83vOxiKDZ3aJ6ehAjYdyr1w5qFL1Cv98ht6vzHleduxwmztPyzy727Zmj0CL5Y gj1BXfi0fKqAsZZGbr0bQVaJyWE4SpVemoPgBVzUUxWsoonf5mFpPB.wiT3_Ljbz9OjJih5H3vRj X4eUpYqLdF6d.1Ij15Jh_54yusl4r64a4.NHUGtw_zrBzxaVYaOO.z9evOkEoborpDXOkV6A0CgJ cvzJc3y_QJ4Dd_vxTVH4.uKhkjwu.PQrUbjQ6PJAGILdoYElGk5rh9zi2H6W5iAC8txerwIdhHfG D8ZIwz1nu8sx_D63MmdZF6X2fT9GXcg2WxWv03ozSmHOt5q3ilS8P7EAOuzbYhM3zEWUv6X4biEp yjzP7_vBrB16YKovT Received: from sonic.gate.mail.ne1.yahoo.com by sonic314.consmr.mail.bf2.yahoo.com with HTTP; Tue, 11 Jun 2019 15:31:02 +0000 Date: Tue, 11 Jun 2019 15:30:56 +0000 (UTC) From: Markus Vester To: rsgb_lf_group@blacksheep.org Message-ID: <483364676.1177353.1560267056891@mail.yahoo.com> In-Reply-To: <2074026906.578167.1560164412605@mail.yahoo.com> References: <6DB8451D7F3D3947A5918808A59621EA31596319@servigilant.vigilant.local> <5CF283CC.9010701@posteo.de> <6DB8451D7F3D3947A5918808A59621EA5BEB7DAC@servigilant.vigilant.local> <5CF57C41.7020008@posteo.de> <6DB8451D7F3D3947A5918808A59621EA5BEB9071@servigilant.vigilant.local> <5CF75AE7.8080103@posteo.de> <6DB8451D7F3D3947A5918808A59621EA5BEBAD4F@servigilant.vigilant.local> <5CF907FC.803@posteo.de> <6DB8451D7F3D3947A5918808A59621EA5BEBBACC@servigilant.vigilant.local> <5CF9695E.8020006@posteo.de> <6DB8451D7F3D3947A5918808A59621EA5BEBBF0B@servigilant.vigilant.local> <5CFA7580.5070009@posteo.de> <5CFCCD52.2000203@posteo.de> <2074026906.578167.1560164412605@mail.yahoo.com> MIME-Version: 1.0 X-Mailer: WebService/1.1.13634 aolwebmail Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36 X-Spam-Score: -0.2 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: Hi Stefan, looking through stored screenshots from the DL0AO grabber, I noticed a fascinating detail: During night hours where resonant spherics appear around 1670 Hz, mains interference on 1650 and 1 [...] Content analysis details: (-0.2 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [74.6.132.123 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (markusvester[at]aol.com) 0.0 HTML_MESSAGE BODY: HTML included in message -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain X-Scan-Signature: 07fee8d4a4e8ea80934a0e0aaa44e788 Subject: Re: ULF/VLF: Tweek resonances - also on 50 Hz harmonics? Content-Type: multipart/alternative; boundary="----=_Part_1177352_290037510.1560267056889" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: *** X-Spam-Status: No, hits=3.5 required=5.0 tests=FORGED_MUA_MOZILLA,HTML_30_40, 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 ------=_Part_1177352_290037510.1560267056889 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi Stefan, looking through stored screenshots from the DL0AO grabber, I noticed a fasc= inating detail: During night hours where resonant spherics appear around 16= 70 Hz, mains interference on 1650 and 1700 Hz seems to become significantly= stronger as well. This enhancement is also present during quiet nights wit= h low QRN levels. Here's a collection of some recent spectrograms: http://df6nm.bplaced.net/dl0ao/files/dl0ao_vlf2_1650Hz_all.jpg We had always assumed that 50 Hz harmonics were a local effect, due to the = earth antennas picking up stray ground currents from the neighbourhood. How= ever the nighttime enhancement strongly suggests that they may=C2=A0in fact= be emitted by more distant sources, like high-voltage transmission lines, = radiating upwards to the ionosphere.=C2=A0 I wonder if others might be seeing similar effects on their loop antennas? Best 73,Markus (DF6NM) -----Urspr=C3=BCngliche Mitteilung----- Von: DK7FC An: rsgb_lf_group Verschickt: So, 9. Jun. 2019 11:14 Betreff: ULF/VLF: Tweak resonance measurements Hi ULF/VLF friends, Last wednesday there was a heavy local thunderstorm with cloud-earthbut als= o with cloud-cloud lightnings. The latter produce well visibletweak resonan= ce patterns in spectrograms taken from the H field. Thefundamental frequenc= y is at a wavelength where the distance betweenground and D-layer is just L= ambda/2, i.e. near 1650 Hz. But they alsoappear at integer multiples. Such = peaks can reach in the order of 20 dBabove the level besides the resonance = frequency. A reprocessed spectrogram from that night shows such tweaks for a timeof ab= out 6 hours.http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/Tweaks_on_NS-= Loop.png They started in daylight, where the D layer refelction height is lower.Then= the night set in and the resonance frequency went down to about 1638Hz, wh= ich becomes visible in this spectrogram and plot:=20 http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/Tweak-resonances_detail1.= png Again it is a good result done by vlfrx-tools and SpectrumLab. SpecLabs'lon= g term average graph' (red colour in the spectrum) was set todifferent half= time values, 10 minutes was one of the best values. Theplot shows the freq= uency of the highest peak of that graph.Unfortunately the time stamps are n= ot correct, but they are correct forthe spectrogram. It looks like the frequency is reasonably stable=C2=A0 from 21 UTC onwards. Sometimes that frequency is jumping by a few Hz. I guess that isbecause the= location of the lightnings is varying and this will have aneffect. However= the peak is not to small, so it could work to make useof that resonator fo= r amateur transmissions? Also the 2nd resonance at 3305 Hz is quite expressed. The antennaefficiency= at that frequency is much higher so maybe it is a good ideato start in tha= t range. With some luck, there will be a time-stamped and streamable VLF stationat D= L0AO soon. Signals from DL0AO and DK7FC could be joined invlfrx-tools and t= hen analysed side by side in SpecLab. With theplotter, the resonance freque= ncys from both locations could be plottedsynchronuously, which will give a = better impression of the dependencyof the peak resonance from the location. It is the ideal time for analysing such resonances from lightnings,however = not for transmitting amateur signals ;-) 73, Stefan ------=_Part_1177352_290037510.1560267056889 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Hi Stefan,

looking through stored screenshot= s from the DL0AO grabber, I noticed a fascinating detail: During night hour= s where resonant spherics appear around 1670 Hz, mains interference on 1650= and 1700 Hz seems to become significantly stronger as well. This enhanceme= nt is also present during quiet nights with low QRN levels. Here's a collec= tion of some recent spectrograms:

=
http://df6nm.bplaced.net/dl0ao/files/= dl0ao_vlf2_1650Hz_all.jpg

We had always assumed that 50 Hz harmonics were a= local effect, due to the earth antennas picking up stray ground currents f= rom the neighbourhood. However the nighttime enhancement strongly suggests = that they may in fact be emitted by more distant sources, like high-vo= ltage transmission lines, radiating upwards to the ionosphere. 

I wond= er if others might be seeing similar effects on their loop antennas?
<= div style=3D"font-family: arial,helvetica,sans-serif; font-size: 10pt; colo= r: black;" data-mce-style=3D"font-family: arial,helvetica,sans-serif; font-= size: 10pt; color: black;">
Best 73,
Markus (DF6NM)


-----Urspr=C3= =BCngliche Mitteilung-----
Von: DK7FC <selberdenken@po= steo.de>
An: rsgb_lf_group <rsgb_lf_group@blackshee= p.org>
Verschickt: So, 9. Jun. 2019 11:14
Betreff: ULF/VLF: Tweak resonance measurements

Hi ULF/VLF friends,

Last wednesday there was a heavy local thunderstorm with cloud-earth but also with cloud-cloud lightnings. The latter produce well visible tweak resonance patterns in spectrograms taken from the H field. The fundamental frequency is at a wavelength where the distance between ground and D-layer is just Lambda/2, i.e. near 1650 Hz. But they also appear at integer multiples. Such peaks can reach in the order of 20 dB above the level besides the resonance frequency.
A reprocessed spectrogram from that night shows such tweaks for a time of about 6 hours. http://www.iup.uni-heidelberg.de/sc= haefer_vlf/ULF/Tweaks_on_NS-Loop.png
They started in daylight, where the D layer refelction height is lower. Then the night set in and the resonance frequency went down to about 163= 8 Hz, which becomes visible in this spectrogram and plot:
http://www.iup.uni-heidelber= g.de/schaefer_vlf/ULF/Tweak-resonances_detail1.png

Again it is a good result done by vlfrx-tools and SpectrumLab. SpecLabs 'long term average graph' (red colour in the spectrum) was set to different half time values, 10 minutes was one of the best values. The plot shows the frequency of the highest peak of that graph. Unfortunately the time stamps are not correct, but they are correct for the spectrogram.
It looks like the frequency is reasonably stable  from 21 UTC onwards.=
Sometimes that frequency is jumping by a few Hz. I guess that is because the location of the lightnings is varying and this will have an effect. However the peak is not to small, so it could work to make use of that resonator for amateur transmissions?

Also the 2nd resonance at 3305 Hz is quite expressed. The antenna efficiency at that frequency is much higher so maybe it is a good idea to start in that range.

With some luck, there will be a time-stamped and streamable VLF station at DL0AO soon. Signals from DL0AO and DK7FC could be joined in vlfrx-tools and then analysed side by side in SpecLab. With the plotter, the resonance frequencys from both locations could be plotted synchronuously, which will give a better impression of the dependency of the peak resonance from the location.

It is the ideal time for analysing such resonances from lightnings, however not for transmitting amateur signals ;-)


73, Stefan


------=_Part_1177352_290037510.1560267056889--