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 vBIKnoHW021205 for ; Mon, 18 Dec 2017 21:49:53 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1eR2HV-0002tf-Dy for rs_out_1@blacksheep.org; Mon, 18 Dec 2017 20:45:01 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1eR2HU-0002tU-Po for rsgb_lf_group@blacksheep.org; Mon, 18 Dec 2017 20:45:00 +0000 Received: from omr-a009e.mx.aol.com ([204.29.186.49]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.89) (envelope-from ) id 1eR2HR-0004rS-IC for rsgb_lf_group@blacksheep.org; Mon, 18 Dec 2017 20:44:59 +0000 Received: from mtaomg-aao01.mx.aol.com (mtaomg-aao01.mx.aol.com [172.27.21.15]) by omr-a009e.mx.aol.com (Outbound Mail Relay) with ESMTP id DF19438000B7 for ; Mon, 18 Dec 2017 15:44:55 -0500 (EST) Received: from core-ace05b.mail.aol.com (core-ace05.mail.aol.com [172.27.23.5]) by mtaomg-aao01.mx.aol.com (OMAG/Core Interface) with ESMTP id E729838000086 for ; Mon, 18 Dec 2017 15:44:54 -0500 (EST) Received: from 188.194.222.230 by webjas-vae046.srv.aolmail.net (10.96.23.49) with HTTP (WebMailUI); Mon, 18 Dec 2017 15:44:52 -0500 Date: Mon, 18 Dec 2017 15:44:54 -0500 From: Markus Vester To: rsgb_lf_group@blacksheep.org Message-Id: <1606b5f3f19-1b25-60732@webjas-vae046.srv.aolmail.net> In-Reply-To: <5A381F2B.7000304@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=1513629895; bh=rXi7g1gotS3nykNrzYRaVSDDAHpJaup4YoxQfQDKX4M=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=cplGxyiiU9qgMbRMP9Am1PN9Z7MpFfZl3BFG8Q3IBQioHbQkbGht34M9NbX97g5nF xTGT6NO3LXVkzoRej1qx8GXrmUfREH4R/R/6GnFO3p1ixomCImtEvQOfb47aaS5JJW LugGXwnLE5T5zOO00lSoT3d2h5LKu0tT57fXj+AE= x-aol-sid: 3039ac1b150f5a3828c65653 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, why give up? At -2.5 dB EbN0, Mike and Paul already had about 65% of the required energy for three characters. That's about 2 out of 3, or one character's worth left to do. Now throwing that away and starting afresh, you'll have to do twice the work.... [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 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 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: ee37f4b261e58bbaf6a18fc5319c092e Subject: Re: VLF: Transatlantic success East to West Content-Type: multipart/alternative; boundary="----=_Part_524511_770470127.1513629892377" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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_524511_770470127.1513629892377 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hi Stefan, why give up? At -2.5 dB EbN0, Mike and Paul already had about 65% of the re= quired energy for three characters. That's about 2 out of 3, or one charact= er's worth left to do. Now throwing that away and starting afresh, you'll h= ave to do twice the work.... =20 One could also send a reference carrier to enable phase alignment before st= acking, without "cheating" by using known message content, One practical wa= y would be to unbalance the PSK by reducing the shift from +-90=C2=B0 to e.= g. +-60=C2=B0, which would spend 25% of the transmitted energy for a -6 dB = reference carrier. Best 73, Markus =20 -----Urspr=C3=BCngliche Mitteilung-----=20 Von: DK7FC An: rsgb_lf_group Verschickt: Mo, 18. Dez 2017 21:06 Betreff: Re: VLF: Transatlantic success East to West Thanks Paul for the summary.=20 Well, 8 days already and it gets worse. I think the phase changes are not = from my side, so it must be the path. I think i will give up now with this 3 character message. But even a faile= d attempt gives us a set of data showing the difficulties and phase variati= ons.=20 On the other side, a single character message is to short to let it be as = it is. So i'm trying a new message with just 2 characters before going down= to 5170 Hz. If possible, i daily feedback is apprechated. f =3D 17470.1000 Hz Start time: 18.Dec.2017 21:30:00 UTC Symbol period: 45 s Characters: 2 CRC bits: 14 Coding 16K21A Duration: 09:12 [hh:mm]=20 Antenna current: 1.2 A 73, Stefan Am 18.12.2017 18:56, schrieb Paul Nicholson:=20 Results from eight overnight transmissions of the=20 3 character message:=20 2017-12-10/11 Eb/N0 =3D -13.1 dB=20 2017-12-11/12 Eb/N0 =3D -6.3 dB, phase 125.3=20 2017-12-12/13 Eb/N0 =3D -6.8 dB, phase 143.2=20 2017-12-13/14 Eb/N0 =3D -19.6 dB (stopped 03:40 by safety limit)=20 2017-12-14/15 Eb/N0 =3D -6.0 dB, phase 68.8=20 2017-12-15/16 Eb/N0 =3D -11.0 dB=20 2017-12-16/17 Eb/N0 =3D -14.6 dB=20 2017-12-17/18 Eb/N0 =3D -9.9 dB, phase 37.0 (stopped 04:19 by snow)=20 Stacking=20 11/12 + 12/13 gives Eb/N0 =3D -3.6 dB.=20 11/12 + 12/13 + 14/15 gives Eb/N0 =3D -3.0 dB.=20 11/12 + 12/13 + 14/15 + 15/16 gives Eb/N0 =3D -2.5 dB.=20 11/12 + 12/13 + 14/15 + 17/18 gives Eb/N0 =3D -3.4 dB.=20 There's some phase changing going on here which is making=20 stacking not so effective.=20 --=20 Paul Nicholson=20 -- ------=_Part_524511_770470127.1513629892377 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Hi Stefan,

why give up? At -2.5 dB Eb= N0, Mike and Paul already had about 65% of the required energy fo= r three characters. That's about 2 out of 3, or one character's worth = left to do. Now throwing that away and starting afresh, you'll have to=  do twice the work....     
<= br>One could also send a reference carrier to enable phase alignm= ent before stacking, without "cheating" by using known message content, One= practical way would be to unbalance the PSK by reducing the = ;shift from +-90=C2=B0 to e.g. +-60=C2=B0, which would spend 25% of the tra= nsmitted energy for a -6 dB reference carrier.

Best 73,
Markus  

-----Urspr=C3=BCngliche Mitte= ilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Mo, 18. Dez 2017 21:06
Betreff: Re: VLF: Tra= nsatlantic success East to West

Thanks Paul for the summary.

Well, 8 days already and it gets worse. I think the phase changes are not from my side, so it must be the path.
I think i will give up now with this 3 character message. But even a failed attempt gives us a set of data showing the difficulties and phase variations.

On the other side, a single character message is to short to let it be as it is. So i'm trying a new message with just 2 characters before going down to 5170 Hz.
If possible, i daily feedback is apprechated.

f =3D 17470.1000 Hz
Start time: 18.Dec.2017  21:30:00 UTC
Symbol period: 45 s
Characters: 2
CRC bits: 14
Coding 16K21A
Duration: 09:12 [hh:mm]
Antenna current: 1.2 A

73, Stefan



Am 18.12.2017 18:56, schrieb Paul Nicholson:

Results from eight overnight transmissions of the
3 character message:

 2017-12-10/11  Eb/N0 =3D -13.1 dB
 2017-12-11/12  Eb/N0 =3D  -6.3 dB, phase 125.3
 2017-12-12/13  Eb/N0 =3D  -6.8 dB, phase 143.2
 2017-12-13/14  Eb/N0 =3D -19.6 dB (stopped 03:40 by safety limit= )
 2017-12-14/15  Eb/N0 =3D  -6.0 dB, phase 68.8
 2017-12-15/16  Eb/N0 =3D -11.0 dB
 2017-12-16/17  Eb/N0 =3D -14.6 dB
 2017-12-17/18  Eb/N0 =3D  -9.9 dB, phase 37.0 (stopped 04:1= 9 by snow)

Stacking

 11/12 + 12/13 gives Eb/N0 =3D -3.6 dB.
 11/12 + 12/13 + 14/15 gives Eb/N0 =3D -3.0 dB.
 11/12 + 12/13 + 14/15 + 15/16 gives Eb/N0 =3D -2.5 dB.
 11/12 + 12/13 + 14/15 + 17/18 gives Eb/N0 =3D -3.4 dB.

There's some phase changing going on here which is making
stacking not so effective.

--
Paul Nicholson
--

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