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 vBUDhZr8014501 for ; Sat, 30 Dec 2017 14:43:38 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1eVHMS-0003bd-0a for rs_out_1@blacksheep.org; Sat, 30 Dec 2017 13:39:40 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1eVHMR-0003bU-Fv for rsgb_lf_group@blacksheep.org; Sat, 30 Dec 2017 13:39:39 +0000 Received: from omr-a010e.mx.aol.com ([204.29.186.54]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.89) (envelope-from ) id 1eVHMN-0007pl-S2 for rsgb_lf_group@blacksheep.org; Sat, 30 Dec 2017 13:39:38 +0000 Received: from mtaomg-aao02.mx.aol.com (mtaomg-aao02.mx.aol.com [172.27.21.16]) by omr-a010e.mx.aol.com (Outbound Mail Relay) with ESMTP id C1C413800058 for ; Sat, 30 Dec 2017 08:39:33 -0500 (EST) Received: from core-acx10e.mail.aol.com (core-acx10.mail.aol.com [172.27.155.135]) by mtaomg-aao02.mx.aol.com (OMAG/Core Interface) with ESMTP id 5B87E38000082 for ; Sat, 30 Dec 2017 08:39:33 -0500 (EST) Received: from 188.194.222.230 by webjas-vae049.srv.aolmail.net (10.96.23.52) with HTTP (WebMailUI); Sat, 30 Dec 2017 08:39:32 -0500 Date: Sat, 30 Dec 2017 08:39:32 -0500 From: Markus Vester To: rsgb_lf_group@blacksheep.org Message-Id: <160a7a62949-171d-2f322@webjas-vae049.srv.aolmail.net> In-Reply-To: <5A479303.5010100@posteo.de> MIME-Version: 1.0 X-MB-Message-Source: WebUI X-MB-Message-Type: User X-Mailer: JAS STD X-Originating-IP: [188.194.222.230] x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20150623; t=1514641173; bh=Z01wjUAEq6SPbBQRCKnsL7/KLoeefozf13WJ5m2wwps=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=G4PG2nsBFNxzzO9ertQTX3jmcaHf9JFg4CuRortbx1XOXI2wK6WYrqEtjbvC+WAGg EVSn0EInoavLNjOvPvYobHzPX3iUupasE80iOvwPBfMvMu+3SQtpL9uT5RAHN5+nfV M5lIQzE4C5MW5BYAxGEEtRrqMDPdjgm6oQ2QEGj8= x-aol-sid: 3039ac1b15105a4797157a9a X-Spam-Score: 0.0 (/) 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 the administrator of that system for details. Content preview: Hi Stefan, > ... and it would also rise the question if using 3rd party propagation data is allowed to get a valid decode at all... In my opinion, the answer is yes. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (markusvester[at]aol.com) -0.0 T_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: 80dfd4418e586cee7526d670ae10acbc Subject: Re: LF: VLF NA Ebnaut Content-Type: multipart/alternative; boundary="----=_Part_249449_1707785130.1514641172809" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=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_249449_1707785130.1514641172809 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hi Stefan, > ... and it would also rise the question if using 3rd party propagation da= ta is allowed to get a valid decode at all... In my opinion, the answer is yes. 73 and all the best, Markus -----Urspr=C3=BCngliche Mitteilung-----=20 Von: DK7FC An: rsgb_lf_group Verschickt: Sa, 30. Dez 2017 14:24 Betreff: Re: LF: VLF NA Ebnaut Thanks Jim, I would be helpful to understand what causes these phase variations. And=20 in a next step it would be nice to learn how to predict / estimate the=20 phase variation. This would allow to correct the phase, for getting a=20 (valid) decode. But that is probably not easy at all and it would also=20 rise the question if using 3rd party propagation data is allowed to get=20 a valid decode at all... 73 es HNY, Stefan Am 29.12.2017 21:53, schrieb hvanesce@comcast.net: > Stefan and Paul, > > I had been guessing issues in or near the receiver, as in your comments b= elow, and the near field reference sounded like a great idea. > > I thought I would mention that on a few occasions I've been surprised by = atypical phase variations on minutes or hours timescales for signals along = similar paths, down the US east coast over land-water-land-water-land-water= -land... paths at distances up to 1500 km or so, when concurrent signal pha= se in (for example) Florida (mostly water path) and inland (all land) at ro= ughly similar SSW bearings looked stable. On one such occasion I checked ph= ase sensitivity of the high-variability path (many land-water transitions) = using LWPC, and compared with sensitivity of the mostly-water and all-land = paths using LWPC. The LWPC comparison was qualitatively similar to the empi= rical comparison: high sensitivity of phase to ionospheric variations along= the path with many land-water transitions. Guessing this is not the explan= ation for VO1NA-Forest night-to-night phase variations, but I thought I'd m= ention it, perhaps for future reference. I thought briefly about ice variat= ions along the path but guessed that any ice would be far too thin to matte= r. > > Also thought I would mention that in general, for path lengths shorter th= an 1000 km or so, lower VLF frequencies generally have larger groundwave-sk= ywave-interference phase variations on minutes/hours/diurnal timescales tha= n do higher VLF frequencies, but this should not generally be a factor at 8= 270 Hz for distances much greater than 1000 km, i.e. not a likely factor on= the VO1NA-Forest path. > > 73, > > Jim AA5BW > > > -----Original Message----- > From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blac= ksheep.org] On Behalf Of DK7FC > Sent: Friday, December 29, 2017 10:43 AM > To: rsgb_lf_group@blacksheep.org > Subject: Re: LF: VLF NA Ebnaut > > Am 29.12.2017 08:51, schrieb Paul Nicholson: >=20 >> I've examined the software at Forest and all appears to be working >> fine, at least as well as my own. >>=20 > OK Paul, thanks for working that out. > > A near field reference for testing the phase stability is certainly a goo= d idea. It should be there all the time ideally. Then one could even correc= t the faulty segments. A safety redundance. > >=20 >> If we see distant >> MSK phase changing (which we probably will), is it caused by >> the rx or the propagation? Alpha signals are a bit tricky >> to use when there are two transmitters interleaved in the signal being >> averaged. >>=20 > In my Alpha RDF spectrogram, the colours (indicating the phase) are repro= ducing day by day quite nicely. There are 2 glitches. One is when the TX sw= itches the phase at 0 clock Moscow time. The other glitch is at > 0 UTC. Then there is the slow change of the phase between day and night. > I am in another location and it is another path though. > >=20 >> Perhaps just the weakness of the signal at Forest? >> Eb/N0 -0.1 =3D S/N 7.5 dB in the 30.6 uHz bandwidth in which the phase >> is measured. >>=20 > Could be the reason. But you are comparing just 2 or 3 days. On my 1 char= acter message at 17470.1 Hz there were no unexpected phase changes > > Another idea could be a damage in an electrical component in the high imp= edance preamp. Maybe a water drop that changes the capacity somewhere, lead= ing to a phase shift. This would not affect the timing but the phase Just a= guess. > > I find it most useful to get an overview of the system performance by loo= king on a 'wideband' spectrogram, covering e.g. 0...24 kHz and half a day o= r a day. You will immediately see if something changed, like the signal lev= els, the phase and timing and sample rate correction (when running an Alpha= plot for example). Or you will see if a new QRM source appeared or disappe= ared. All this without a particular search for eventual errors, just the us= ual daily view on that spectrogram. I would feel blind without that :-) > > So in the end, is it propagation or not? For me it sound unlikely that it= is propagation. On 17.4701 kHz, over such a distance, maybe. But not on 82= 70 Hz on the path between VO1NA and Mike. > Uuh, another strange idea: Maybe a faulty component in the preamp that ch= anges the phase frequency dependently, like a capacitor moving the edge fre= quency of a LPF or HPF and changing the phase hereby? > > 73, Stefan > > > > > ------=_Part_249449_1707785130.1514641172809 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Hi Stefan,

> ... and it would als= o rise the question if using 3rd party propagation data is allowed to get a= valid decode at all...

In my opinion, the answer is&nb= sp;yes.

73 and all the best,
Markus

-----Ursp= r=C3=BCngliche Mitteilung-----
Von: DK7FC <selberdenken= @posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blackshe= ep.org>
Verschickt: Sa, 30. Dez 2017 14:24
Betreff: Re: LF: VLF NA Ebnaut

Th= anks Jim,

I would be helpful to understand= what causes these phase variations. And
in a next step it= would be nice to learn how to predict / estimate the
phas= e variation. This would allow to correct the phase, for getting a
(valid) decode. But that is probably not easy at all and it would= also
rise the question if using 3rd party propagation dat= a is allowed to get
a valid decode at all...

73 es HNY, Stefan

Am 2= 9.12.2017 21:53, schrieb hvanesce@comcast.net:
> Stefan and Paul,
>
> I had been guessing issues in or near t= he receiver, as in your comments below, and the near field reference sounde= d like a great idea.
>
> I thought I = would mention that on a few occasions I've been surprised by atypical phase= variations on minutes or hours timescales for signals along similar paths,= down the US east coast over land-water-land-water-land-water-land... path= s at distances up to 1500 km or so, when concurrent signal phase in (for ex= ample) Florida (mostly water path) and inland (all land) at roughly similar= SSW bearings looked stable. On one such occasion I checked phase sensitivi= ty of the high-variability path (many land-water transitions) using LWPC, a= nd compared with sensitivity of the mostly-water and all-land paths using L= WPC. The LWPC comparison was qualitatively similar to the empirical compari= son: high sensitivity of phase to ionospheric variations along the path wit= h many land-water transitions. Guessing this is not the explanation for VO1= NA-Forest night-to-night phase variations, but I thought I'd mention it, pe= rhaps for future reference. I thought briefly about ice variations along th= e path but guessed that any ice would be far too thin to matter.
>
> Also thought I would mention that in genera= l, for path lengths shorter than 1000 km or so, lower VLF frequencies gener= ally have larger groundwave-skywave-interference phase variations on minute= s/hours/diurnal timescales than do higher VLF frequencies, but this should = not generally be a factor at 8270 Hz for distances much greater than 1000 k= m, i.e. not a likely factor on the VO1NA-Forest path.
><= br abp=3D"2754">> 73,
>
> Jim AA5B= W
>
>
> -----Origi= nal Message-----
> From: owner-rsgb_lf_group@blacksheep.org [mailto:owner= -rsgb_lf_group@blacksheep.org] On Behalf Of DK7FC
> = Sent: Friday, December 29, 2017 10:43 AM
> To: rsgb_lf_group@blacksh= eep.org
> Subject: Re: LF: VLF NA Ebnaut
>
> Am 29.12.2017 08:51, schrieb Paul Nicholson:=
>
>> I've examined the softwa= re at Forest and all appears to be working
>> fine, a= t least as well as my own.
>>
&= gt; OK Paul, thanks for working that out.
>
> A near field reference for testing the phase stability is certainl= y a good idea. It should be there all the time ideally. Then one could even= correct the faulty segments. A safety redundance.
>
>
>> If we see distant
>> MSK phase changing (which we probably will), is it caused by=
>> the rx or the propagation? Alpha signals are a = bit tricky
>> to use when there are two transmitters = interleaved in the signal being
>> averaged.
>>
> In my Alpha RDF spectrogram, = the colours (indicating the phase) are reproducing day by day quite nicely.= There are 2 glitches. One is when the TX switches the phase at 0 clock Mos= cow time. The other glitch is at
> 0 UTC. Then there is = the slow change of the phase between day and night.
> I = am in another location and it is another path though.
><= br abp=3D"2788">>
>> Perhaps just the weakness= of the signal at Forest?
>> Eb/N0 -0.1 =3D S/N 7.5 d= B in the 30.6 uHz bandwidth in which the phase
>> is = measured.
>>
> Could be the = reason. But you are comparing just 2 or 3 days. On my 1 character message a= t 17470.1 Hz there were no unexpected phase changes
>> Another idea could be a damage in an electrical componen= t in the high impedance preamp. Maybe a water drop that changes the capacit= y somewhere, leading to a phase shift. This would not affect the timing but= the phase Just a guess.
>
> I find i= t most useful to get an overview of the system performance by looking on a = 'wideband' spectrogram, covering e.g. 0...24 kHz and half a day or a day. Y= ou will immediately see if something changed, like the signal levels, the p= hase and timing and sample rate correction (when running an Alpha plot for = example). Or you will see if a new QRM source appeared or disappeared. All = this without a particular search for eventual errors, just the usual daily = view on that spectrogram. I would feel blind without that :-)
>
> So in the end, is it propagation or not? For m= e it sound unlikely that it is propagation. On 17.4701 kHz, over such a dis= tance, maybe. But not on 8270 Hz on the path between VO1NA and Mike.
> Uuh, another strange idea: Maybe a faulty component in the p= reamp that changes the phase frequency dependently, like a capacitor moving= the edge frequency of a LPF or HPF and changing the phase hereby?
>
> 73, Stefan
>
>
>
>
&g= t;


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