Return-Path: Received: from mtain-dl10.r1000.mx.aol.com (mtain-dl10.r1000.mx.aol.com [172.29.74.216]) by air-ma07.mail.aol.com (v129.4) with ESMTP id MAILINMA073-b52e4d07a22731a; Tue, 14 Dec 2010 11:58:15 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dl10.r1000.mx.aol.com (Internet Inbound) with ESMTP id DE9E6380030FF; Tue, 14 Dec 2010 11:56:05 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PSY9T-0007pV-Fo for rs_out_1@blacksheep.org; Tue, 14 Dec 2010 16:54:59 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PSY9S-0007pM-UQ for rsgb_lf_group@blacksheep.org; Tue, 14 Dec 2010 16:54:58 +0000 Received: from mail-iw0-f171.google.com ([209.85.214.171]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PSY9P-00055Q-K3 for rsgb_lf_group@blacksheep.org; Tue, 14 Dec 2010 16:54:58 +0000 Received: by iwn2 with SMTP id 2so982863iwn.16 for ; Tue, 14 Dec 2010 08:54:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=ZGgabAWv0bQ51j7V87yuLnDz3cRCypsM30tkohu9Hbg=; b=m5Ma6WJ+YDpCB4lSIxSPSfSj2B4lyJDG/BbgAOjannB9M/vXVMu87BPR0WqVdaiPjq AXYExRYBPz8OppUmHLBEhjqV/KsNRUdgQjfOei6JARJ2BM1oehoXoFVDboAkF/6T5rpE a55uqKRmFyPth+Qm3cAQoKU1Vd3awaGnfilX4= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=j5bNQ9zzk0v0jeaAjiDy1bGHGS7r4PxySn7EjnzA/EcE9hy5odHTLWl+AXI8JrVIhJ MYwmp/x0ZC/ACHuNNC1l58eY7LsJoLwnnTZvNrb5b8dk6YWTBmL7xbacpm/g/sOIdXI/ exWRvhRiOIIXYfMS/KjFkqVK9WxvRFGrl0W0Q= MIME-Version: 1.0 Received: by 10.231.32.76 with SMTP id b12mr3453264ibd.162.1292345693476; Tue, 14 Dec 2010 08:54:53 -0800 (PST) Received: by 10.231.200.211 with HTTP; Tue, 14 Dec 2010 08:54:53 -0800 (PST) In-Reply-To: References: <80E0204D3E534137903FE0B8E499597F@IBM7FFA209F07C> <4D0783FC.3090107@iup.uni-heidelberg.de> Date: Tue, 14 Dec 2010 16:54:53 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: Earth Electrodes Content-Type: multipart/alternative; boundary=0022152d6f61fc97fb049761ad81 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 x-aol-global-disposition: G X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m229.2 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d4ad84d07a1a54b9b X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --0022152d6f61fc97fb049761ad81 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Google "Project Sanguine" http://www.fas.org/nuke/guide/usa/c3i/fs_clam_lake_elf2003.pdf suggest= s more than 60km of cable used at 76Hz, so pro-rata not dissimiliar to 600m earth spacing at 9kHz However, they do use two synchronised transmitters, so the effective baseline becomes far greater. Now, how abot that for 8970Hz. Two stattion using low cost simple GPSDOs and similar DDS / synthesizers can reasonably guarantee their respective frequencies accuracy to 10^-9 short term At 10kHz (to keep numbers simple= ), that is a differnece freq of no more than 10^-5, or 100000 seconds, or one cycle in just over a day. And over this period, GPS derived sources will average out as spot-on. So, for low cost simple amateur coherent wide spaced VLF signalling frequency is not an issue. SIgnal element timing can be synchronised to sub microsecnds, again using GPS timing. Maybe worth thinking about. Reading the posts so far, 'JNT interest coul= d be rekindled, so may yet apply for my NoV - although with a total house pl= ot of only some 25 x 7 metres, there not really any scope for Tx antennas unless I use ground wires looping over the garden wall into and along the road at the back Andy www.g4jnt.com On 14 December 2010 16:27, Chris wrote: > HiStefan, > Yes, but 600m is VERY long! The wire even laying on the ground I would > expect to radiate quite well at 137 with that length! And how many watts= ?? > ERP?? > I am sure 8970 would do well *through the ground* at the sort of powers > being spoken about. Probably ideal for submarines, as Roger says! > Vy 73, Chris, G4AYT. > > ----- Original Message ----- > *From:* Stefan Sch=E4fer > *To:* rsgb_lf_group@blacksheep.org > *Sent:* Tuesday, December 14, 2010 2:49 PM > *Subject:* Re: LF: Earth Electrodes > > Hi Chris, > > But how do you explain that i have crossed 49.6 km with a 600m spaced ea= rth > electrode antenna on 8970 Hz? It was rather summer time than winther > (regarding QRN)! With the same antenna, my 137 kHz signal was seen 20 dB > above noise near Paris in DFCW-3!????? > > 73, Stefan > > > Am 14.12.2010 15:15, schrieb Chris: > > Hi Mal, > Yes, that is what I had concluded years ago. No harm in trying though! > Further to your previous e-mail to LF, looks to me like beacons are now > becoming the norm on 136/7kHz band and below. I have no problem with tha= t > personally, indeed, I think it preferable to a QSO taking forever! I wou= d > like to see full idents though, no matter how slow. > Vy 73, > Chris, G4AYT. > > --0022152d6f61fc97fb049761ad81 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Google "Project Sanguine"
=A0
=A0
However, they do use two synchronised transmitters, so the effective= baseline becomes far greater.=A0=A0
=A0
Now, how abot that for 8970Hz.=A0=A0 Two stattion using low cost simp= le GPSDOs and similar DDS / synthesizers can reasonably guarantee their re= spective frequencies=A0accuracy to=A010^-9=A0short term=A0 At 10kHz (to ke= ep numbers=A0simple), that is a differnece freq of no more than 10^-5, or= 100000 seconds, or one cycle in just over a day.=A0 And over this period,= GPS derived sources will average out as spot-on.
=A0
So, for low cost simple amateur coherent wide spaced VLF signalling= frequency is not an issue.=A0=A0=A0 SIgnal element timing can be synchron= ised to sub microsecnds, again using GPS timing.
=A0
Maybe worth thinking about.=A0=A0 Reading the posts so far, 'JNT= interest could be rekindled, so may yet apply for my NoV - although with= a total house plot of only some 25 x =A07=A0 metres, there not really any= scope for Tx antennas unless I use ground wires looping over the garden= wall into and along=A0the road at the back
=A0
Andy
=A0


=A0
On 14 December 2010 16:27, Chris <c.ashby435@btinternet= .com> wrote:
HiStefan,
Yes, but 600m is VERY long! The wire= even laying on the ground I would expect to radiate quite well at 137 wit= h that length! And how many watts?? ERP??
I am sure 8970 would do well thro= ugh the ground at the sort of powers being spoken about. Probably ide= al for submarines, as Roger says!
Vy 73, Chris, G4AYT.
----- Original Message -----
Sent: Tuesday, December 14, 2010 2:= 49 PM
Subject: Re: LF: Earth Electrodes

Hi Chris,

But how do you explain that i have crossed= 49.6 km with a 600m spaced earth electrode antenna on 8970 Hz? It was rat= her summer time than winther (regarding QRN)! With the same antenna, my 13= 7 kHz signal was seen 20 dB above noise near Paris in DFCW-3!?????

73, Stefan


Am 14.12.2010 15:15, schrieb Chris:=20
Hi Mal,
Yes, that is what I had concluded yea= rs ago. No harm in trying though!
Further to your previous e-mail to LF= , looks to me like beacons are now becoming the norm on 136/7kHz band and= below. I have no problem with that personally, indeed, I think it prefera= ble to a QSO taking forever! I woud like to see full idents though, no mat= ter how slow.
Vy 73,
Chris, G4AYT.

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