Return-Path: <owner-rsgb_lf_group@blacksheep.org> Received: from mtain-dc01.r1000.mx.aol.com (mtain-dc01.r1000.mx.aol.com [172.29.64.129]) by air-df06.mail.aol.com (v127_r1.1) with ESMTP id MAILINDF063-5ef84b9ec03b33; Mon, 15 Mar 2010 19:18:19 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dc01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 5DC34380000C5; Mon, 15 Mar 2010 19:18:17 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NrJTJ-0000WJ-ST for rs_out_1@blacksheep.org; Mon, 15 Mar 2010 23:13:17 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NrJTJ-0000WA-CT for rsgb_lf_group@blacksheep.org; Mon, 15 Mar 2010 23:13:17 +0000 Received: from imr-da01.mx.aol.com ([205.188.105.143]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from <markusvester@aol.com>) id 1NrJTG-0006mU-BT for rsgb_lf_group@blacksheep.org; Mon, 15 Mar 2010 23:13:17 +0000 Received: from mtaout-mb01.r1000.mx.aol.com (mtaout-mb01.r1000.mx.aol.com [172.29.41.65]) by imr-da01.mx.aol.com (8.14.1/8.14.1) with ESMTP id o2FND0l1017883 for <rsgb_lf_group@blacksheep.org>; Mon, 15 Mar 2010 19:13:00 -0400 Received: from Black (g229121179.adsl.alicedsl.de [92.229.121.179]) by mtaout-mb01.r1000.mx.aol.com (WebSuites/MUA Thirdparty client Interface) with ESMTPA id B0A9FE000101 for <rsgb_lf_group@blacksheep.org>; Mon, 15 Mar 2010 19:12:59 -0400 (EDT) Message-ID: <CFF7007088334878BC0C967CF5AEB4D9@Black> From: "Markus Vester" <markusvester@aol.com> To: <rsgb_lf_group@blacksheep.org> References: <Pine.LNX.3.95.1100225172510.244A-100000@noname.nodomain.nowhere> In-Reply-To: <Pine.LNX.3.95.1100225172510.244A-100000@noname.nodomain.nowhere> Date: Tue, 16 Mar 2010 00:12:14 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6000.16480 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6000.16669 x-aol-global-disposition: G x-aol-sid: 3039ac1d29414b9ebefb132d X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: Ionospheric VLF propagation Content-Type: multipart/alternative; boundary="----=_NextPart_000_007A_01CAC49D.551353C0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_20_30,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-sid: 3039ac1d40814b9ec0391d72 X-AOL-IP: 193.82.116.20 ------=_NextPart_000_007A_01CAC49D.551353C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dear LF, on the phone, Stefan mentioned that he was running about 0.4 A into th= e nearly vertical (70=B0), 100 m long kite antenna. Thus radiated powe= r would be=20 EMRP =3D 1579 ohm * (0.4 A * sin(70=B0) * 50 m / 33 km)^2 =3D 0.5 mW= =3D -3 dBm. Using 1/distance field decay above lossless flat earth, at 830 km we= would expect a field strength E =3D -3 + 49.5 - 20 log (830) dBuV/m =3D -12 dBuV/m. However Paul's calibrated spectrum at 14:38 UT showed a peak B =3D 3.1= fT at 8970 Hz, equivalent to an electrical field E =3D c * B =3D 0.93 uV/m =3D - 0.5 dBuV/m. Taking into account a couple of dB's for measurement uncertainties, we= are still left with an observed signal very significantly stronger th= an expected. This seems to support Alexander's statement about a slowe= r than inverse distance decay in the two-dimensional ionosphere-earth= waveguide. On http://freenet-homepage.de/df6nm/vlf/vlf_DHO_dualfreq.htm , I have= another observation pointing out an ionospheric effect on VLF. In 200= 6, the German naval transmitter DHO38, normally on 23.4 kHz, was simul= taneously transmitting on 18.5 kHz as well. Surprisingly the fieldstre= ngths and the diurnal patterns for the two frequencies appeared to be= completely different, presumably due to different phaseshifts between= ground and skywave component. Best regards, MArkus (DF6NM) ----- Original Message -----=20 From: Alexander S. Yurkov=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, February 25, 2010 6:53 PM Subject: Re: LF: AW: 9 Dreamers Hellow, Stefan. > If that calculation is reasonably correct, what distance could be= =20 > reached with 1,4mW @ 8,9 kHz=20 With such a condition you'll get about 2.5 uV/m at 100 km. Seems it= can be recievid. If there is no atmospheric and industrial noise it should= be very strong signal. But all depends on noise on 9 kHz. I have no ide= as about noise on 9 kHz. I neglet ionosphere in estimations. But at D= =3D100 km it should be approximately right.=20 Anyway if you can use 100 m high antenna then few of 100's km you sh= ould reach. May be substantionally more. For large distances dependance= of E on D changes. On the distances more then ~100 km field should have behaviour E ~ sqrt(1/D). This yelds only 10 dB attenuation if distan= ce became 10 times more. Thus if you'll have 20 dB over noise at 100 km= (if noise is 0.25 uV/m for example) then you'll have ~10 dB over noise= at 1000 km. =20 Do it if you have such an oportunity! It is very interesting. Regards, Alexander ------=_NextPart_000_007A_01CAC49D.551353C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=3DContent-Type content=3D"text/html; charset=3Diso-88= 59-1"> <META content=3D"MSHTML 6.00.6000.16982" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV><FONT face=3DArial size=3D2> <DIV><FONT face=3DArial size=3D2>Dear LF,</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>on the phone, Stefan mentioned that= he was running=20 about 0.4 A into the nearly vertical (70=B0), 100 m long kit= e=20 antenna. Thus radiated power would be </FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2> EMRP =3D 1579 ohm *= (0.4 A * sin(70=B0)=20 * 50 m / 33 km)^2 =3D 0.5 mW =3D -3 dBm.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>Using 1/distance field decay above lo= ssless flat=20 earth, at 830 km we would expect a field strength</FONT></DI= V> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2> E =3D -3 + 49.5 - 20 log (830)= dBuV/m =3D -12=20 dBuV/m.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV> <DIV><FONT face=3DArial size=3D2>However Paul's calibrated spectrum at= 14:38 UT=20 showed a peak B =3D 3.1 fT at 8970 Hz, equivalent to an elec= trical=20 field</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2> E =3D c * B =3D 0.93 uV/m =3D= - 0.5=20 dBuV/m.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>Taking into account a couple of= dB's=20 for measurement uncertainties, we are still left with an observed= signal=20 very significantly stronger than expected. This seems t</FONT><FONT fa= ce=3DArial size=3D2>o support Alexander's statement&n= bsp;about a slower=20 than inverse distance decay in the two-dimensional ionospher= e-earth=20 waveguide.</FONT></DIV> <DIV> </DIV> <DIV><FONT face=3DArial size=3D2>On <FONT face=3DArial size=3D2><= A href=3D"http://freenet-homepage.de/df6nm/vlf/vlf_DHO_dualfreq.htm"= >http://freenet-homepage.de/df6nm/vlf/vlf_DHO_dualfreq.htm</A></FONT>= =20 , I have another observation pointing out an ionospheri= c effect=20 on VLF. In 2006, the German naval transmitter DHO38, normall= y on 23.4=20 kHz, was simultaneously transmitting on 18.5 kHz as=20 well. Surprisingly the fieldstrengths and the diurnal patterns fo= r the two=20 frequencies appeared to be completely different, presumably due= to=20 different phaseshifts between ground and skywave component.</FONT></DI= V> <DIV> </DIV> <DIV>Best regards,</DIV> <DIV>MArkus (DF6NM)</DIV> <DIV> </DIV></DIV></FONT></DIV> <BLOCKQUOTE style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-L= EFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV> <DIV style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color:= black"><B>From:</B>=20 <A title=3Dfitec@omskcity.com href=3D"mailto:fitec@omskcity.com">Ale= xander S.=20 Yurkov</A> </DIV> <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A title=3Drsgb_lf_group@= blacksheep.org href=3D"mailto:rsgb_lf_group@blacksheep.org">rsgb_l= f_group@blacksheep.org</A>=20 </DIV> <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Thursday, February 25,= 2010 6:53=20 PM</DIV> <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: LF: AW: 9 Dreame= rs</DIV> <DIV><FONT face=3DArial size=3D2></FONT><FONT face=3DArial size=3D2>= </FONT><FONT face=3DArial size=3D2></FONT><BR></DIV>Hellow, Stefan= .<BR><BR>> If that=20 calculation is reasonably correct, what distance could be <BR>>= reached=20 with 1,4mW @ 8,9 kHz <BR><BR>With such a condition you'll get about= 2.5 uV/m=20 at 100 km. Seems it can be<BR>recievid. If there is no atmospheric= and=20 industrial noise it should be<BR>very strong signal. But all depends= on noise=20 on 9 kHz. I have no ideas<BR>about noise on 9 kHz. I neglet ionosphe= re in=20 estimations. But at D=3D100 km<BR>it should be approximately right.= =20 <BR><BR>Anyway if you can use 100 m high antenna then few of 100's= km you=20 should<BR>reach. May be substantionally more. For large distances de= pendance=20 of E<BR>on D changes. On the distances more then ~100 km field shoul= d=20 have<BR>behaviour E ~ sqrt(1/D). This yelds only 10 dB attenuation= if=20 distance<BR>became 10 times more. Thus if you'll have 20 dB over noi= se at 100=20 km (if<BR>noise is 0.25 uV/m for example) then you'll have ~10 dB ov= er noise=20 at 1000<BR>km. <BR><BR>Do it if you have such an oportunity!= It is very=20 interesting.<BR><BR>Regards,<BR>Alexander<BR></BLOCKQUOTE></BODY></H= TML> ------=_NextPart_000_007A_01CAC49D.551353C0--