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[195.171.43.25]) by mx.google.com with ESMTP id fr3si3227077wib.71.2014.03.16.10.01.33 for ; Sun, 16 Mar 2014 10:01:33 -0700 (PDT) Received-SPF: neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) client-ip=195.171.43.25; Authentication-Results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) smtp.mail=owner-rsgb_lf_group@blacksheep.org; dkim=fail (test mode) header.i=@btinternet.com Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1WPEKn-00012J-4Q for rs_out_1@blacksheep.org; Sun, 16 Mar 2014 16:54:49 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1WPEKm-00012A-Dz for rsgb_lf_group@blacksheep.org; Sun, 16 Mar 2014 16:54:48 +0000 Received: from smtpout15.bt.lon5.cpcloud.co.uk ([65.20.0.135]) by relay1.thorcom.net with esmtp (Exim 4.82) (envelope-from ) id 1WPEKi-0006Wx-LG for rsgb_lf_group@blacksheep.org; Sun, 16 Mar 2014 16:54:47 +0000 X-CTCH-RefID: str=0001.0A090206.5325D753.00A7,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-Junkmail-Premium-Raw: score=12/97,refid=2.7.2:2014.3.16.142114:17:12.731,ip=,rules=__HAS_MSGID, __SANE_MSGID, MSGID_32HEX_LC, INVALID_MSGID_NO_FQDN, __MSGID_32HEX, __HAS_FROM, __PHISH_FROM2, __FRAUD_WEBMAIL_FROM, __TO_MALFORMED_2, __TO_NO_NAME, __BOUNCE_CHALLENGE_SUBJ, __BOUNCE_NDR_SUBJ_EXEMPT, __SUBJ_ALPHA_END, __MIME_VERSION, __CT, __CTYPE_MULTIPART_ALT, __CTYPE_HAS_BOUNDARY, __CTYPE_MULTIPART, __HAS_X_PRIORITY, __HAS_MSMAIL_PRI, __HAS_X_MAILER, USER_AGENT_OE, __OUTLOOK_MUA_1, __USER_AGENT_MS_GENERIC, __ANY_URI, __CP_MEDIA_BODY, __CP_URI_IN_BODY, __SUBJ_ALPHA_NEGATE, SUPERLONG_LINE, __HTML_FONT_BLUE, __HAS_HTML, BODY_SIZE_10000_PLUS, __MIME_HTML, __TAG_EXISTS_HTML, __STYLE_RATWARE_NEG, __URI_NS, HTML_50_70, __PHISH_FROM, __OUTLOOK_MUA, __FRAUD_WEBMAIL, FORGED_MUA_OUTLOOK X-CTCH-Spam: Unknown Received: from gnat (81.129.181.41) by smtpout15.bt.lon5.cpcloud.co.uk (8.6.100.99.10223) (authenticated as alan.melia@btinternet.com) id 5321F9D700297EFA for rsgb_lf_group@blacksheep.org; Sun, 16 Mar 2014 16:54:42 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btinternet.com; s=btcpcloud; t=1394988884; bh=3Q7uMCCf8a1lbZYiXjoORUvHmVmLybMBHbk9OzJmBO4=; h=Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:X-Mailer; b=pbiOoFT7ING6CGyebELCLaVai9/YxtBpoyoerUNAByFyffxtXgDiK01W2kCMXWG8PJGRvBwryw3EAo2O8QF7ASpj50jTUFJX3s8msm9XsS8NBH9g+179P7yhaikOnk569E8C6hhbwNZ74vShALA9d4Uu3IpZOM9mK9cADzqLAyo= Message-ID: <693C340E9C0542DABE7821331538ACA8@gnat> From: "Alan Melia" To: References: <094701cf411d$421dcce0$c65966a0$@comcast.net> Date: Sun, 16 Mar 2014 16:54:41 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hi Jim interesting looking papers.....I visited GBR in about 1962 which was when it was still essentially in the "build state" of circa 1926 .....banks of 20 50kW water cooled tubes :-) We were taken into the tuning loft (it would not happen these days .....we were asked to remove any watches or jewellry. The prize was to see the 4inch diameter "rope" of 6000 odd strand litz supported on a white oak frame (no metal parts or nails) trashing around as the key went down. The party trick was a 60 watt fluorescent tube lit to full brighness and wavedaround by the guide. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [65.20.0.135 listed in list.dnswl.org] 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: e6ca507e494efc41e4b71d154e5805b0 Subject: LF: Re: DHO Link Content-Type: multipart/alternative; boundary="----=_NextPart_000_0008_01CF4138.6CF5DD20" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.1 required=5.0 tests=FORGED_MUA_OUTLOOK,HTML_40_50, 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 This is a multi-part message in MIME format. ------=_NextPart_000_0008_01CF4138.6CF5DD20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Jim interesting looking papers.....I visited GBR in about 1962 which = was when it was still essentially in the "build state" of circa 1926 = .....banks of 20 50kW water cooled tubes :-) We were taken into the = tuning loft (it would not happen these days .....we were asked to remove = any watches or jewellry. The prize was to see the 4inch diameter "rope" = of 6000 odd strand litz supported on a white oak frame (no metal parts = or nails) trashing around as the key went down. The party trick was a 60 = watt fluorescent tube lit to full brighness and wavedaround by the = guide. The point was that GBR was not phase stabilised until the1967 re-build. = I dont know what the phase variations were, but the re-build was to = enable it to be used for time transfer and comparison and as a precursor = to the Omega VLF nav system. Alan G3NYK ----- Original Message -----=20 From: hvanesce=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Sunday, March 16, 2014 1:39 PM Subject: LF: DHO Link Markus, =20 Thanks for the DHO diurnal plot. =20 It's a memorable image, with interesting symmetries.=20 =20 I remain hopeful of finding or making a model that qualitatively = represents VLF amplitude and phase diurnals for a substantial percentage = of cases. This would be very helpful in preparing for DX, QRP and other = activities. =20 Thomson has done some great work in this area (VLF diurnals). I was = surprised to find that he reverted (prior to 2011) to Wait's 2-parameter = ionospheric reflection model (using h and beta*, and adjusting them = empirically), instead of using LWPC or ModeFinder (which he mentions = require more knowledge of ionospheric parameters than is currently = available: = http://www.physics.otago.ac.nz/space/Thomson_LongPath_paper_JGR_2011.pdf = ; I thought Paul might also find this point interesting) =20 To make matters more interesting, Han = (http://people.ee.duke.edu/~cummer/reprints/132_Han11_JGR_DaytimeDRegionS= harpness.pdf ) recently showed considerable and substantial = disagreement (qualitative and quantitative) between beta* parameters = values derived (empirically) by a number of expert sources including = Thomson. Han's findings are well-summarized on the last page of his = paper. The kind of discrepancies shown by Han seem (to me) suggest a lot = of work remaining on the way to good diurnal amplitude and phase models. = Among the four expert sources on D-region beta cited by Han, there were = three different findings on the polarity of the change in beta with = zenith angle: decreasing beta with increasing zenith angle (1 of 4), = increasing beta with increasing zenith angle (2 of 4), relatively = constant beta with increasing zenith angle (1 of 4); not to mention = considerable disagreement between the four sources in magnitude of = sensitivity of beta to zenith angle. All of this is clearly summarized = on the last page of the paper. =20 I thought you might find the paragraph above interesting because it = shows a significant gap in the understanding of some basics that affect = (at some distances and on some days) whether VLF daytime signal strength = increases or decreases. In his conclusion, Han describes the magnitude = of disagreement in derived values for beta as surprising. He suggests = that the two-parameter model may not be sufficient (a circumstance that = Thomson hoped to avoid, see above) =20 On a related topic, Han's method of deriving beta (using broadband = signals) is interesting and appears to have substantial merit, but I'm = guessing that the available broadband sources used by Han (sferics) come = with their own issues in this type of measurement.=20 =20 I think I can end on a light note: if you have a chance to look at one = figure and one paragraph in this paper by Volland: = http://nvlpubs.nist.gov/nistpubs/jres/68D/jresv68Dn2p225_A1b.pdf , Adobe = Reader page 4 (document page 228), including Figure 3 and the paragraph = including "A remarkable exception from this rule has been observed in = Lindau (Germany), Figure 3 shows two successive daily phase variations = of GBR. Such phase inversions are rare.", I think you may find something = interesting, odd or even humorous.=20 =20 * (D-region electron density sharpness) =20 Regards, =20 Jim =20 ------=_NextPart_000_0008_01CF4138.6CF5DD20 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Jim interesting looking papers.....I = visited GBR=20 in about 1962 which was when it was still essentially in the "build = state" of=20 circa 1926  .....banks of 20  50kW water cooled tubes  = :-) =20 We were taken into the tuning loft (it would not happen these days = .....we were=20 asked to remove any watches or jewellry. The prize was to see the 4inch = diameter=20 "rope" of 6000 odd strand litz supported on a white oak frame (no metal = parts or=20 nails) trashing around as the key went down. The party trick was a 60 = watt=20 fluorescent tube lit to full brighness and wavedaround by the=20 guide.
 
The point was that GBR was not phase = stabilised=20 until the1967 re-build. I dont know what the phase variations were, but = the=20 re-build was to enable it to be used for time transfer and comparison = and as a=20 precursor to the Omega VLF nav system.
 
Alan
G3NYK
 
----- Original Message -----
From:=20 hvanesce=20
Sent: Sunday, March 16, 2014 = 1:39=20 PM
Subject: LF: DHO Link

Markus,

 

Thanks=20 for the DHO diurnal plot.

 

It=92s=20 a memorable image, with interesting symmetries.

 

I=20 remain hopeful of finding or making a model that qualitatively = represents VLF=20 amplitude and phase diurnals for a substantial percentage of cases. = This would=20 be very helpful in preparing for DX, QRP and other=20 activities.

 

Thomson=20 has done some great work in this area (VLF diurnals). I was surprised = to find=20 that he reverted (prior to 2011) to Wait=92s 2-parameter ionospheric = reflection=20 model (using h and beta*, and adjusting them empirically), instead of = using=20 LWPC or ModeFinder (which he mentions require more knowledge of = ionospheric=20 parameters than is currently available:  http://www.physics.otago.ac.nz/space/Thomson_LongPath_paper_JGR_= 2011.pdf=20 ; I thought Paul might also find this point = interesting)

 

To=20 make matters more interesting, Han (http://people.ee.duke.edu/~cummer/reprints/132_Han11= _JGR_DaytimeDRegionSharpness.pdf=20  ) recently showed considerable and substantial disagreement = (qualitative=20 and quantitative) between beta* parameters values derived = (empirically) by a=20 number of expert sources including Thomson. Han=92s findings are = well-summarized=20 on the last page of his paper. The kind of discrepancies shown by Han = seem (to=20 me) suggest a lot of work remaining on the way to good diurnal = amplitude and=20 phase models. Among the four expert sources on D-region beta cited by = Han,=20 there were three different findings on the polarity of the change in = beta with=20 zenith angle:  decreasing beta with increasing zenith angle (1 of = 4),=20 increasing beta with increasing zenith angle (2 of 4), relatively = constant=20 beta with increasing zenith angle (1 of 4); not to mention = considerable=20 disagreement between the four sources in magnitude of sensitivity of = beta to=20 zenith angle. All of this is clearly summarized on the last page of = the=20 paper.

 

I=20 thought you might find the paragraph above interesting because it = shows a=20 significant gap in the understanding of some basics that affect (at = some=20 distances and on some days) whether VLF daytime signal strength = increases or=20 decreases. In his conclusion, Han describes the magnitude of=20  disagreement in derived values for beta as surprising. He = suggests that=20 the two-parameter model may not be sufficient (a circumstance that = Thomson=20 hoped to avoid, see above)

 

On=20 a related topic, Han=92s method of deriving beta (using broadband = signals) is=20 interesting and appears to have substantial merit, but I=92m guessing = that the=20 available broadband sources used by Han (sferics) come with their own = issues=20 in this type of measurement.

 

I=20 think I can end on a light note: if you have a chance to look at one = figure=20 and one paragraph in this paper by Volland: http://nvlpubs.nist.gov/nistpubs/jres/68D/jresv68Dn2p225_A1b.pdf=20 , Adobe Reader page 4 (document page 228), including Figure 3 and the=20 paragraph including =93A = remarkable=20 exception from this rule has been observed in Lindau (Germany), Figure = 3 shows=20 two successive daily phase variations of GBR=85 Such phase inversions = are=20 rare=85=94, I=20 think you may find something interesting, odd or even = humorous.

 

 =20 *  (D-region electron density sharpness)

 

Regards,

 

Jim

 

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