Return-Path: Received: from mtain-md07.r1000.mx.aol.com (mtain-md07.r1000.mx.aol.com [172.29.96.91]) by air-mb06.mail.aol.com (v129.4) with ESMTP id MAILINMB061-a6fc4d07b0b01c7; Tue, 14 Dec 2010 13:00:16 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-md07.r1000.mx.aol.com (Internet Inbound) with ESMTP id 24C9E3800030E; Tue, 14 Dec 2010 13:00:14 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PSZ9r-0000XI-Ry for rs_out_1@blacksheep.org; Tue, 14 Dec 2010 17:59:27 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PSZ9r-0000X8-5u for rsgb_lf_group@blacksheep.org; Tue, 14 Dec 2010 17:59:27 +0000 Received: from mail-iw0-f171.google.com ([209.85.214.171]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PSZ9o-0005gh-RR for rsgb_lf_group@blacksheep.org; Tue, 14 Dec 2010 17:59:27 +0000 Received: by iwn2 with SMTP id 2so1046865iwn.16 for ; Tue, 14 Dec 2010 09:59:23 -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=KelMCa9HrrMUraYJA6L0bIjGNCD6UcUn0zo6QKUQ5B4=; b=DmUyISGaW2c262BEUjh5zOkiS9m2lTiGH/UdQ5qvfP4fCNUqkkfP7On+GDVjTe+05z 0AL3gWx7R9hhoTRWy+3t/f6z2ESkTB+V7MPHGpfTpcVJdIVQq5jwtkhloB4FmND8uqWs 69gUA34ISKaU3pqnh8lJCFDm41w+7fBEaKTqo= 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=VXP3ngJo+SC9ZMtLxvl3Bq/hgA+s9ZUvHatZLqhjpUCAth9fje4nRm/MpD0CxpPQa0 MNFNzYWhcr1+OsYaQXpu3Rt8cj1RRUoFLRZoH2LIsZax8v1au4PygDDRHltGvRcce+6N +7lnqgWGvErvudknFfZ64EukyWrCnu3XRl0Io= MIME-Version: 1.0 Received: by 10.231.199.10 with SMTP id eq10mr3584373ibb.112.1292349562970; Tue, 14 Dec 2010 09:59:22 -0800 (PST) Received: by 10.231.200.211 with HTTP; Tue, 14 Dec 2010 09:59:22 -0800 (PST) In-Reply-To: References: <80E0204D3E534137903FE0B8E499597F@IBM7FFA209F07C> <4D0783FC.3090107@iup.uni-heidelberg.de> Date: Tue, 14 Dec 2010 17:59:22 +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=90e6ba4fc4c6a06507049762949f X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_20_30, HTML_FONTCOLOR_UNSAFE,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-m210.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d605b4d07b0ad5328 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --90e6ba4fc4c6a06507049762949f Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Yes, I suppose over the whole radiating space all you're really doing is adding the total powers of the two or more statons. I suppose was really thinking long baselines leading to high gains - which would need some coordination and of dubious value? But, if the two stations were partially in their near field regions, some additional mechanisms could perhaps come into play. Surely two coherent sources coupling into the same E/H region could give some additional effcects - somehow. Ideally raising the mutual radiation resistance to alter the antenna efficiency perhaps ? Just throwing ideas into the air. But at least its not technology limited= . A while back I remember reading Moxon's HF Antenna Book and seeing the concept of supergain coming into play - which appears to be a critical coupling thing. Perhaps someone who understands antennas in the way Moxo= n did - not just being able to drive NEC - could comment? Andy www.g4jnt.com On 14 December 2010 17:14, Roger Lapthorn wrote: > Andy, > > Surely two synchronised TX systems can only increase ERP by 3dB maximum? > ...or am I missing something? > > Yes, 600m baseline is similar to Sanguine *pro rata* with frequency and > that system got a megawatt TX output signal around the world and to a > considerable depth in the ocean with 100% reliability. Luckily we don't= need > to reach the ocean floors, so our ERP can be somewhat lower (!). A 600m > baseline would not be that difficult to arrange for a portable test out= in > the countryside or across National Trust land or woodlands. > > 73s > Roger G3XBM > > > On 14 December 2010 16:54, Andy Talbot wrote: > >> Google "Project Sanguine" >> >> http://www.fas.org/nuke/guide/usa/c3i/fs_clam_lake_elf2003.pdf >> suggests more than 60km of cable used at 76Hz, so pro-rata not dissimil= iar >> 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 GPS= DOs >> and similar DDS / synthesizers can reasonably guarantee their respectiv= e >> frequencies accuracy to 10^-9 short term At 10kHz (to keep numbers sim= ple), >> 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 wi= ll >> 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 >> could be rekindled, so may yet apply for my NoV - although with a total >> house plot 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 an= d >> 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 wat= ts?? >>> ERP?? >>> I am sure 8970 would do well *through the ground* at the sort of power= s >>> 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 >>> earth electrode antenna on 8970 Hz? It was rather summer time than win= ther >>> (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 no= w >>> becoming the norm on 136/7kHz band and below. I have no problem with= that >>> personally, indeed, I think it preferable to a QSO taking forever! I= woud >>> like to see full idents though, no matter how slow. >>> Vy 73, >>> Chris, G4AYT. >>> >>> >> > > > -- > g3xbm-qrp.blogspot.com/ > www.g3xbm.co.uk > www.youtube.com/user/g3xbm > G3XBM GQRP 1678 ISWL G11088 > --90e6ba4fc4c6a06507049762949f Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Yes, I suppose over the whole=A0radiating space=A0all you're real= ly doing is adding the total powers of the two or more statons.=A0=A0 I su= ppose was really thinking long baselines leading to high gains - which wou= ld need some coordination and of dubious value?
=A0
But, if the two stations were partially in their near field regions,= some additional mechanisms could perhaps=A0come into play.=A0=A0 Surely= two coherent sources coupling into the same E/H region could give some ad= ditional effcects - somehow.=A0=A0 Ideally raising the mutual radiation re= sistance to alter the antenna efficiency perhaps ?
=A0
Just throwing ideas into the air.=A0 But at least its not technology= limited.
=A0
A while back I remember reading Moxon's HF Antenna Book and seein= g the concept of supergain coming into play - which appears to be a critic= al coupling thing.=A0=A0 Perhaps someone who understands antennas=A0in the= way=A0Moxon did - not just being able to drive NEC - could comment?
=A0
Andy
=A0


=A0
On 14 December 2010 17:14, Roger Lapthorn <rogerlapthorn@= gmail.com> wrote:
Andy,

Surely two synchr= onised TX systems can only increase ERP by 3dB maximum? ...or am I missing= something?

Yes, 600m baseline is similar to Sanguine pro rata with frequen= cy and that system got a megawatt TX output signal around the world and to= a considerable depth in the ocean with 100% reliability. Luckily we don&#= 39;t need to reach the ocean floors, so our ERP can be somewhat lower (!).= A 600m baseline would not be that difficult to arrange for a portable tes= t out in the countryside or across National Trust land or woodlands.

73s
Roger G3XBM=20


On 14 December 2010 16:54, Andy Talbot <an= dy.g4jnt@gmail.com> wrote:
Google "Project Sanguine"
=A0
=A0 http://www.fas.org/nuke/guide/usa/c3i/fs_clam_= lake_elf2003.pdf=A0=A0 suggests more than=A060km of cable used at 76Hz= , so pro-rata not dissimiliar to 600m earth spacing at 9kHz
=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.a= shby435@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 throu= gh 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
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.




--
g3xbm-qrp.blogs= pot.com/
www.g3xbm.co.uk<= br>www.you= tube.com/user/g3xbm
G3XBM=A0=A0 GQRP 1678=A0=A0=A0 ISWL G11088

--90e6ba4fc4c6a06507049762949f--