Return-Path: X-Spam-DCC: paranoid 1290; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=BAYES_00,HTML_40_50, HTML_MESSAGE,NO_REAL_NAME autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id sBTBKKcL022559 for ; Mon, 29 Dec 2014 12:20:22 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Y5YDD-0005mj-Mn for rs_out_1@blacksheep.org; Mon, 29 Dec 2014 11:10:11 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Y5YDD-0005ma-9b for rsgb_lf_group@blacksheep.org; Mon, 29 Dec 2014 11:10:11 +0000 Received: from smtp-out01.xworks.net ([31.25.48.13]) by relay1.thorcom.net with esmtps (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.84) (envelope-from ) id 1Y5YDA-000301-WC for rsgb_lf_group@blacksheep.org; Mon, 29 Dec 2014 11:10:10 +0000 Received: from MAILBACKEND4 (cluster06.xworks.net [10.100.1.80]) by smtp-out01.xworks.net (Postfix) with ESMTP id B65B1613E0 for ; Mon, 29 Dec 2014 12:10:06 +0100 (CET) X-DKIM-Result: Domain=kabelmail.de Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kabelmail.de; s=mail; t=1419851406; bh=QR5ZKlqHVDwQVCs1lkMUom3PMwiO6Y+rssl0SVImeuA=; h=Date:From:To:Subject; b=C9q0e8BMANtZQ0Xmo+x9V9lV5k4dbY0ETYyrxCHDQtKghGdjIdlY96MBXN6oMrMd6 G4eU7lJlaGuOWpzOgKx45goVsQfFV9wtjfhIzbdlYT5sAWktogtbD8xtIX1ujgoMOn dEvtxXujT+Zkx47J7FRtAI5BI3RC+kUhKPnzsEQY= Date: Mon, 29 Dec 2014 12:10:05 +0100 From: uwe-jannsen@kabelmail.de To: rsgb_lf_group@blacksheep.org Message-ID: X-Priority: 3 (Normal) MIME-Version: 1.0 X-Scan-Signature: 617a5faed955112e448650f4d003a84d Subject: VLF: 8270 Hz BPSK Content-Type: multipart/alternative; boundary="----458A810700304FDEB885BCA5AEA04E75" 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: RO X-Status: X-Keywords: X-UID: 1651 ------458A810700304FDEB885BCA5AEA04E75 Content-type: text/plain; charset=Windows-1252 Content-Transfer-Encoding: quoted-printable Paul,=20 are you aware of my yesterdays transmission/message? Uwe Von: rsgb_lf_group@blacksheep=2Eorg Gesendet: 24=2E12=2E2014 16:08 An: rsgb_lf_group@blacksheep=2Eorg Betreff: Re: Re: VLF: 8270 Hz BPSK Paul, Markus,=20 OK:, new constellation: =20 Code:Rate 1/18 K =3D 25 Characters: 25 10sec/symb 1520 signal bits duration: 4h14sec =20 TX time: 11:00 to 16:00, day: when the WX will be fine=2E=20 Uwe/dj8wx=20 Von: rsgb_lf_group@blacksheep=2Eorg Gesendet: 22=2E12=2E2014 21:59 An: rsgb_lf_group@blacksheep=2Eorg Betreff: Re: VLF: 8270 Hz BPSK Uwe wrote: > I would prefer Rate 1/8K =3D 25 out of your convolution code > message generator, i=2Ee=2E 560bits in 4h40min=2E Your last transmission I think was on 2014-11-07 and I just examined the recording: You were S/N 14=2E7dB in 278uHz between 12:00 and 14:00=2E Signal is strong enough to send data quite fast=2E You could use 14 second symbols to send 10 characters (800 signal bits in 03:06:40) for a virtually certain decode=2E A more challenging test with 11 second symbols would still have 95% chance of correct decode=2E So far the best radio amateur message transmission at VLF was by Markus DF6NM on 2014-05-18 when he sent 14 characters across 1028km=2E If we use product of distance and characters as a metric then that's a score of 14392 kmchars=2E At 762km you would have to send 19 or more characters to beat that=2E Daytime should allow a 4 hour message without trouble=2E Rate 1/8, 11 second symbols, 21 characters (1328 bits in 04:03:28)=2E Avoid the terminators=2E Send around midday +/- 2 hours=2E On 2014-12-14 I wrote: > http://abelian=2Eorg/vlf/tmp/141219c=2Epng > From 00:00 to 08:00 it averaged 12=2E6dB S/N in 278uHz, 0=2E14fT=2E > That's enough signal to send 27 characters at a rate of 22 > information bits per hour=2E I gave this a test using a recording of W4DEX carrier from that night=2E Modulating the recording with a BPSK message 27 characters long, rate 1/16 K=3D25 with a symbol period of only 7=2E5 seconds and it decoded correctly with a small margin to spare=2E 9 second symbols decoded with plenty of margin=2E -- Paul Nicholson http://abelian=2Eorg/ -- ------458A810700304FDEB885BCA5AEA04E75 Content-type: text/html; charset=Windows-1252 Content-Transfer-Encoding: quoted-printable

Paul,
are you aware of my yesterdays transmission/message?
Uwe


Von: rsg= b_lf_group@blacksheep=2Eorg
G= esendet: 24=2E12=2E2014 16:08
A= n: rsgb_lf_group@blacksheep=2Eorg
B= etreff: Re: Re: VLF: 8270 Hz BPSK

Paul, Markus,

OK:, new constellation:

Code:Rate 1/18 K =3D 25
Characters: 25
10sec/symb
1520 signal bits
duration: 4h14sec

TX time: 11:00 to 16:00, day: when t= he WX will be fine=2E

Uwe/dj8wx

Von: rsg= b_lf_group@blacksheep=2Eorg
G= esendet: 22=2E12=2E2014 21:59
A= n: rsgb_lf_group@blacksheep=2Eorg
B= etreff: Re: VLF: 8270 Hz BPSK

Uwe wrote:

> I would prefer Rate 1/8K =3D 25 out of your convolution code
> message generator, i=2Ee=2E 560bits in 4h40min=2E

Your last transmission I think was on 2014-11-07 and I just
examined the recording: You were S/N 14=2E7dB in 278uHz between
12:00 and 14:00=2E Signal is strong enough to send data quite
fast=2E You could use 14 second symbols to send 10 characters
(800 signal bits in 03:06:40) for a virtually certain decode=2E

A more challenging test with 11 second symbols would still
have 95% chance of correct decode=2E

So far the best radio amateur message transmission at VLF was
by Markus DF6NM on 2014-05-18 when he sent 14 characters across
1028km=2E If we use product of distance and characters as a metric
then that's a score of 14392 kmchars=2E

At 762km you would have to send 19 or more characters to beat
that=2E Daytime should allow a 4 hour message without trouble=2E
Rate 1/8, 11 second symbols, 21 characters (1328 bits in 04:03:28)=2E Avoid the terminators=2E Send around midday +/- 2 hours=2E

On 2014-12-14 I wrote:

> http://abelian=2Eorg/vlf/tmp/141219c=2Epng

> From 00:00 to 08:00 it averaged 12=2E6dB S/N in 278uHz, 0=2E14fT=2E=
> That's enough signal to send 27 characters at a rate of 22
> information bits per hour=2E

I gave this a test using a recording of W4DEX carrier from
that night=2E Modulating the recording with a BPSK message 27
characters long, rate 1/16 K=3D25 with a symbol period of only 7=2E5 seconds and it decoded correctly with a small margin to spare=2E
9 second symbols decoded with plenty of margin=2E

--
Paul Nicholson
http://abelian=2Eorg/
--
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