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[195.171.43.25]) by mx.google.com with ESMTP id b2si296696wja.1.2013.11.05.00.12.47 for ; Tue, 05 Nov 2013 00:12:48 -0800 (PST) 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=pass (test mode) header.i=@comcast.net Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1VdbDV-0004Vz-Hl for rs_out_1@blacksheep.org; Tue, 05 Nov 2013 07:38:25 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1VdbDU-0004Vq-E2 for rsgb_lf_group@blacksheep.org; Tue, 05 Nov 2013 07:38:24 +0000 Received: from qmta02.emeryville.ca.mail.comcast.net ([76.96.30.24]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1VdbDP-0000fg-H3 for rsgb_lf_group@blacksheep.org; Tue, 05 Nov 2013 07:38:23 +0000 Received: from omta02.emeryville.ca.mail.comcast.net ([76.96.30.19]) by qmta02.emeryville.ca.mail.comcast.net with comcast id ljdv1m0010QkzPwA2jeGbD; Tue, 05 Nov 2013 07:38:16 +0000 Received: from Owner ([166.147.71.189]) by omta02.emeryville.ca.mail.comcast.net with comcast id ljdu1m008451mrJ8Nje0r6; Tue, 05 Nov 2013 07:38:11 +0000 From: "hvanesce" To: References: <05b201ced8d7$24e85fe0$6eb91fa0$@comcast.net> <2FA25F9F5AB648A98C2F0C7A96F0D1B2@gnat> <02CA06069FC74FEAAEF85930320E0E34@White> In-Reply-To: Date: Tue, 5 Nov 2013 01:37:47 -0600 Message-ID: <06db01ced9f9$f6e4b1b0$e4ae1510$@comcast.net> MIME-Version: 1.0 X-Mailer: Microsoft Outlook 14.0 Thread-Index: AQL566ZJqJHlorSnw6nR1wDqLzSvowIbdoyDAf97+wUB4kYjTgHpWqYXl4DbgUA= Content-Language: en-us DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20121106; t=1383637097; bh=tSt0nELbPUJTaZu7HCpzxbf0b31nf2gSAyHYNcoZxzw=; h=Received:Received:From:To:Subject:Date:Message-ID:MIME-Version: Content-Type; b=przFguCMGb5pezSER71DJg707pB2LndqActD0auizLmEmDYPqnq9PkUEb+9IMdFmR bLdZrMT7hbtntMQS2v99wKdPsNYVG07c4bKrgYqOqCqvdcpeT7pJc/xXUYLD8ZCV8i 4q83n4mhO9bfpv+Aj9az1HyrL3qHMe5Zo+fnnbyU1G5sHjwC+NWWHlhIqZliWWN/Xb 8bqGIJNzArZGAoITtEBjQEwd8gk8oCGtp9TDmDoeD/ATD5TGXmx78QTgXRbvmrjddQ ZcnCWg2/2MdsQBFY5QFvTvxj7Yz6h10PTbPwxcwr/o9cE0J0QmlVq0DsmS5UkvPR8k tTg+wQtgzfr9Q== 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: Alan and Markus, Thank you for your feedback on ray-hop characteristics including Loran references, and many other effects, in the context of LF phase reinforcement. It will be enjoyable to consider new data with these insights. [...] 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 [76.96.30.24 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (hvanesce[at]comcast.net) -0.0 SPF_PASS SPF: sender matches SPF record -0.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 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: 7a2474f8514b50a7ab468c8b7bdbd65d Subject: RE: LF: Re: RE: Hartmut's Grabber On Last Night... Content-Type: multipart/alternative; boundary="----=_NextPart_000_06DC_01CED9C7.AC4BEF60" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.2 required=5.0 tests=HTML_50_60,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 Status: O X-Status: X-Keywords: X-UID: 1661 This is a multipart message in MIME format. ------=_NextPart_000_06DC_01CED9C7.AC4BEF60 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Alan and Markus, Thank you for your feedback on ray-hop characteristics including Loran references, and many other effects, in the context of LF phase reinforcement. It will be enjoyable to consider new data with these insights. Also just received my first copy of "LF Today"; thanks for the reference in an earlier message. 73, Jim AA5BW From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Alan Melia Sent: Sunday, November 3, 2013 7:28 PM To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Re: RE: Hartmut's Grabber On Last Night... Hi Markus....Ah used the wrong thumb :-)) yes I though it did seem odd..... I had taken the low level instead of the difference. A recalc gives hop 3 at -7dB wrt hop 2 that ties in nicely with your Loran figure. The sea hop estimate was based on 136kHz I just assumed that the sea was smoother than land in the wavelength dimension so less scattering. Overland signals to here seemed relatively weaker than Joe's signal, but there is all the problem with antenna efficiency to consider. and there were not many signals at 4000km at the time. Your Loran transmitters area more reliable source. Of course if you take maximum range, the "downcomming" wave comes in tangentialy so grazes rather than "reflects". Fascinating stuff....thanks for your correction....that thumb erased :-)) Alan ----- Original Message ----- From: Markus Vester To: rsgb_lf_group@blacksheep.org Sent: Monday, November 04, 2013 12:00 AM Subject: Re: LF: Re: RE: Hartmut's Grabber On Last Night... Alan, based on Loran-C measurements, I would agree on the ballpark figure of -6 dB per hop. Not sure though if land reflections are really so much worse than seawater, as for low angle incidence the reflection coefficient may still be close to unity. > A 16dB fade suggests 20dB or so difference in amplitude. No. -20 dB = 0.1 x amplitude for the weaker signal. But 1+-0.1 = 1.1...0.9, which would be a very flat fade (1.74 dB max to min). To produce deep fades, the signals would need to be rather similar in magnitude. 73, Markus (DF6NM) From: Alan Melia Sent: Monday, November 04, 2013 12:40 AM To: rsgb_lf_group@blacksheep.org Subject: LF: Re: RE: Hartmut's Grabber On Last Night... Hi Jim yes I think it is a phase effect, the reinforcement/cancellation is probably between 2 hop and 3 hop paths. A 16dB fade suggests 20dB or so difference in amplitude. I used to reckon on about a 12dB per ionospheric hop and less, maybe 6dB, for a sea "bounce" based on signal from Joe VO1NA and the Naval station at Newport Corner near Halifax NS. Each hop has a maximum range of about 2000km. There are several effects around the sunset shadow area that could add to the effect too. Higher angles at the ionosphere may penetrate futher before returning giving higher attenuation to the higher hop modes. A thumbnail calculation suggests hop3 ampltude of about -23dB below hop 2 would give a 17dB fade as it goes in and out of phase. Very much a "hand waving" estimate but a useful empirical guide. Alan G3NYK ----- Original Message ----- From: hvanesce To: rsgb_lf_group@blacksheep.org Sent: Sunday, November 03, 2013 8:56 PM Subject: LF: RE: Hartmut's Grabber On Last Night... Bob, This is the third time that I've noticed Dex's signal peaking substantially (>15dB?) starting around 0500, at approximately the same time that your signal begins a substantial fade. I've seen this twice on captures from Hartmut's grabber, and once on a capture from Mike's grabber. An interesting example is 21 October 2013, when captures by Henny, Mike and Hartmut all showed a fade of roughly 10-15dB in your signal from 0500-0530, with Mike's grabber (which showed Dex's signal clearly around that time) showing a rise in Dex's signal of roughly 10-15dB. I wonder if this could be attributable to modal phase reinforcement/cancellation near the terminator? The relative change between your signal and Dex's seems rather high for that mechanism, but I suppose not out of the question. AGARD CP 305 includes a paper (Morfitt) with some interesting plots in this context, and a number of other papers with interesting propagation studies at frequencies near 74kHz; is there a good place for me to post info of this type? 73, Jim AA5BW From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Bob Raide Sent: Sunday, November 3, 2013 12:07 PM To: rsgb_lf_group@blacksheep.org Subject: LF: Hartmut's Grabber On Last Night... Good shots of Me and Dex-Bob WG2XRS/4 NY [XRS4] and [XRS5]... ------=_NextPart_000_06DC_01CED9C7.AC4BEF60 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Alan and Markus,

 

Thank you for your feedback on ray-hop characteristics including = Loran references, and many other effects, in the context of LF phase = reinforcement. It will be enjoyable to consider new data with these = insights.

 

Also just received my first copy of “LF Today”; thanks = for the reference in an earlier message.

 

73,

 

Jim AA5BW   

 

From:= = owner-rsgb_lf_group@blacksheep.org = [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Alan = Melia
Sent: Sunday, November 3, 2013 7:28 PM
To: = rsgb_lf_group@blacksheep.org
Subject: Re: LF: Re: RE: = Hartmut's Grabber On Last Night...

 

Hi = Markus....Ah used the wrong thumb :-)) yes I though it did seem odd..... = I had taken the low level instead of the difference.  A recalc = gives hop 3 at  -7dB wrt hop 2 that ties in nicely with your Loran = figure. The sea hop estimate was based on 136kHz I just assumed that the = sea was smoother than land in the wavelength dimension so less = scattering. Overland signals to here seemed relatively weaker than Joe's = signal, but there is all the problem with antenna efficiency to = consider. and there were not many signals at 4000km at the time. Your = Loran transmitters area more reliable source. Of course if you take = maximum range, the "downcomming" wave comes in tangentialy so = grazes rather than "reflects". Fascinating stuff....thanks for = your correction....that thumb erased  = :-))

 

Alan

----- = Original Message -----

From:<= /b> Markus Vester =

Sent:<= /b> = Monday, November 04, 2013 12:00 AM

Subject: = Re: LF: Re: RE: Hartmut's Grabber On Last = Night...

 

Alan,<= o:p>

 

based on = Loran-C measurements, I would agree on the ballpark figure of -6 dB = per hop. Not sure though if land reflections are really so much worse = than seawater, as for low angle incidence the reflection = coefficient may still be close to = unity.

 

> A 16dB = fade suggests 20dB or so difference in = amplitude.

 

No. -20 = dB =3D 0.1 x amplitude for the weaker signal. But 1+-0.1 = =3D 1.1...0.9, which would be a very flat fade (1.74 = dB max to min). To produce deep fades, the signals would need = to be rather similar in magnitude.

 

73, =

Markus = (DF6NM)

 <= /o:p>

From:= = Alan Melia =

Sent:= = Monday, November 04, 2013 12:40 AM

Subject: LF: Re: = RE: Hartmut's Grabber On Last = Night...

 

Hi Jim yes I = think it is a phase effect, the reinforcement/cancellation is probably = between 2 hop and 3 hop paths. A 16dB fade suggests 20dB or so = difference in amplitude. I used to reckon on about a 12dB per = ionospheric hop and less, maybe 6dB, for a sea "bounce" based = on signal from Joe VO1NA and the Naval station at Newport Corner near = Halifax NS. Each hop has a maximum range of about 2000km. There are = several effects around the sunset shadow area that could add to the = effect too. Higher angles at the ionosphere may penetrate futher before = returning giving higher attenuation to the higher hop = modes. 

 

A thumbnail = calculation suggests hop3 ampltude of about -23dB below hop 2 would = give a 17dB fade as it goes in and out of = phase.

 

Very much a = "hand waving" estimate but a useful empirical = guide.

 

Alan

G3NYK<= o:p>

----- = Original Message -----

From:<= /b> hvanesce =

Sent:<= /b> = Sunday, November 03, 2013 8:56 PM

Subject: = LF: RE: Hartmut's Grabber On Last = Night...

 

Bob,

 

This is the third time that I’ve noticed Dex’s signal = peaking substantially (>15dB?) starting around 0500, at approximately = the same time that your signal begins a substantial fade. I’ve = seen this twice on captures from Hartmut’s grabber, and once on a = capture from Mike’s grabber.

 

An interesting example is 21 October 2013, when captures by Henny, = Mike and Hartmut all showed a fade of roughly 10-15dB in your signal = from 0500-0530, with Mike’s grabber (which showed Dex’s = signal clearly around that time) showing a rise in Dex’s signal of = roughly 10-15dB.  

 

I wonder if this could be attributable to modal phase = reinforcement/cancellation near the terminator? The relative change = between your signal and Dex’s seems rather high for that = mechanism, but I suppose not out of the question. AGARD CP 305 includes = a paper (Morfitt) with some interesting plots in this context, and a = number of other papers with interesting propagation studies at = frequencies near 74kHz; is there a good place for me to post info of = this type?

 

73,

 

Jim AA5BW

 

From:= = owner-rsgb_lf_group@bl= acksheep.org [mailto:owner-rsgb_lf_g= roup@blacksheep.org] On Behalf Of Bob Raide
Sent: = Sunday, November 3, 2013 12:07 PM
To: rsgb_lf_group@blacksheep.org=
Subject: LF: Hartmut's Grabber On Last = Night...

 

Good shots of Me and = Dex-Bob WG2XRS/4 NY [XRS4] and [XRS5]... =

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