Return-Path: <owner-rsgb_lf_group@blacksheep.org> X-Spam-DCC: paranoid 1290; Body=3 Fuz1=3 Fuz2=3 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, RATWARE_GECKO_BUILD,SPF_PASS 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 u41Ec6df011691 for <sq5bpf@lipkowski.org>; Sun, 1 May 2016 16:38:06 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1awsR0-0000tj-1B for rs_out_1@blacksheep.org; Sun, 01 May 2016 15:33:22 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1awsQz-0000ta-HH for rsgb_lf_group@blacksheep.org; Sun, 01 May 2016 15:33:21 +0100 Received: from mout01.posteo.de ([185.67.36.65]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from <selberdenken@posteo.de>) id 1awsQx-0005Ra-AU for rsgb_lf_group@blacksheep.org; Sun, 01 May 2016 15:33:20 +0100 Received: from dovecot03.posteo.de (dovecot03.posteo.de [172.16.0.13]) by mout01.posteo.de (Postfix) with ESMTPS id 854372099C for <rsgb_lf_group@blacksheep.org>; Sun, 1 May 2016 16:33:16 +0200 (CEST) Received: from mail.posteo.de (localhost [127.0.0.1]) by dovecot03.posteo.de (Postfix) with ESMTPSA id 3qyVKS412yz5vMs for <rsgb_lf_group@blacksheep.org>; Sun, 1 May 2016 16:33:16 +0200 (CEST) Message-ID: <572613AC.90704@posteo.de> Date: Sun, 01 May 2016 16:33:16 +0200 From: DK7FC <selberdenken@posteo.de> User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <1545cc43544-7b51-40b@webprd-a09.mail.aol.com> <57222E30.1080202@posteo.de> <57225653.3090907@abelian.org> <5725FCD5.40606@posteo.de> <57260D6A.3040503@abelian.org> In-Reply-To: <57260D6A.3040503@abelian.org> X-Scan-Signature: 66d07794ca19cd68f7d6cc289cd4ac18 Subject: Re: ULF: EbNaut transmissions on lower frequencies? Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 7964 RR, OK! Do we know enough about the phase behaviour on 8.27 kHz, so we know where we are starting from? For ULF we would need longer symbol periods, that's sure. So it could be interesting first to try 200s periods and a shorter message. 5 characters should be a goal, suitable for a few callsigns of active amateur radio stations :-) 5 characters at 200s symbols, that's 28 hours and 26 minutes and 40 seconds. I will start a transmission at that rate (this time without SL restarting after 24 hours) and at 6 dB lower power (because of the beeeeeeep during the working day tomorrow). 6 dB less (abt 125 mA) should be no problem at that rate. A first pre-test. The cavity resonances are the frequencies seen as a horizontal (diurnal frequency variation) line in this capture from last year: https://dl.dropboxusercontent.com/u/19882028/VLF/dk7fc_VLF_150718_1326.jpg 73, Stefan Am 01.05.2016 16:06, schrieb Paul Nicholson: > > Amateur radio DX at ULF, that would be a result for any > dreamer wouldn't it? > > You've proved that propagation will allow 24hrs at > 8.27kHz, and we expect most lower frequencies will be at > least as stable - so long as we avoid the cavity resonances. > Near those frequencies, dispersion will introduce large > and variable phase delay. > > So avoiding the resonances, and times of geomagnetic > disturbance, and stormy weather in Europe, and being able > to tx and rx for as long as necessary with reliable > equipment, it should be possible even with 14dB weaker signal. > > The first thing to do would be to get a carrier detection > and measure that to estimate the required symbol period. > > -- > Paul Nicholson > -- >