Return-Path: Received: from mtain-dg11.r1000.mx.aol.com (mtain-dg11.r1000.mx.aol.com [172.29.65.19]) by air-md10.mail.aol.com (v129.4) with ESMTP id MAILINMD101-8b984d4aa0ec120; Thu, 03 Feb 2011 07:34:52 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dg11.r1000.mx.aol.com (Internet Inbound) with ESMTP id 15024380000F4; Thu, 3 Feb 2011 07:34:50 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PkyNr-0007kA-NC for rs_out_1@blacksheep.org; Thu, 03 Feb 2011 12:33:59 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PkyNq-0007k1-Ue for rsgb_lf_group@blacksheep.org; Thu, 03 Feb 2011 12:33:58 +0000 Received: from out1.ip06ir2.opaltelecom.net ([62.24.128.242]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PkyNo-00057d-Jw for rsgb_lf_group@blacksheep.org; Thu, 03 Feb 2011 12:33:58 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AsoBAEsvSk1Ok86j/2dsb2JhbACCRZAdA4NijmRzvAaFWASBYI1Ngm0 X-IronPort-AV: E=Sophos;i="4.60,418,1291593600"; d="scan'208,217";a="489355978" Received: from unknown (HELO xphd97xgq27nyf) ([78.147.206.163]) by out1.ip06ir2.opaltelecom.net with SMTP; 03 Feb 2011 12:33:48 +0000 Message-ID: <002301cbc39e$9b03fcd0$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <0DF35BB8-9FC4-4A05-A9B9-675D74FEE669@gmail.com> Date: Thu, 3 Feb 2011 12:33:47 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: RE: More earth-mode tests and a puzzle Content-Type: multipart/alternative; boundary="----=_NextPart_000_0020_01CBC39E.9AC87A70" 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_UNKNOWN,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-sid: 3039ac1d41134d4aa0ea41b1 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_0020_01CBC39E.9AC87A70 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Chris and LF This is the point I have been making for some time, Experimenting with= so called earth mode in an urban environment with a network 0f underg= round pipes and cables of various varieties is a meaningless excercise= .=20 The experiment needs to be conducted in a wide open rural environment= with earth rods used at both the Transmit and Receive end. de mal/g3kev ----- Original Message -----=20 From: Chris=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, February 03, 2011 11:01 AM Subject: Re: LF: RE: More earth-mode tests and a puzzle Hi Roger, Well, in my humble opinion you're use of 'earth' mode and so on is= inaccurate. I think you have proved this more than once with your lac= k of results using your earth rod/house pipes! it seems to me this is= simply conduction through underground pipes and wires. Not totally un= expected. Genuine earth mode would require you to be away from all pip= es etc. and using two earth rods at both ends. Whilst this is interesting, I am not sure if it is anything new or= unexpected, or repeatable in open countryside. Keep up the experiment= ing though! We're all keen to see what you try next!! Vy 73, Chris, G4AYT, Whitstable, Kent, UK. ----- Original Message -----=20 From: Roger Lapthorn=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, February 03, 2011 10:35 AM Subject: Re: LF: RE: More earth-mode tests and a puzzle Hi Rik, I am pretty certain the signal is flowing along the water pipes bu= t that the field around the pipes is much better detected with the E-f= ield probe than with the loop. The EFP works very well outside in the= street too and is far less critical about position and orientation.= With the loop the signal is strong when clearly over the pipe work,= whereas with the EFP one can, it seems, be almost anywhere in the roa= d and house and get a signal. In the house I presume I am picking up= the same sort of signal surrounding the pipes within the property. What I do NOT understand is why I get ZERO signal pick-up from G6A= LB at 3km with another earth-electrode set-up at the RX end. One of my= ground points is the copper central heating radiator which connects= directly to metal pipes in the road. I know this as I use the same se= t-up to launch my own earth-mode signals that can be detected in the= roads with a loop out in the fens >5km away. Logic tells me that if= Andrew G6ALB is launching his signal along pipes from his earth elect= rode pair then I would get strongest signals by also connecting one gr= ound to the metal pipework at the RX end, but this is definitely not= the case as there is absolutely no signal detectable in QRSS3 by this= method, but at least 20dB S/N with the EFP! Can someone explain what= is going on please as I am very baffled! Tomorrow both G6ALB and I will put our beacons on (me on 8.7608kHz= and G6ALB around 8.755kHz) and I will take a trip out into the fens= with both the loop and the E-field probe to see what I detect. It is= possible that with the EFP I may be able to detect the signal(s) at= greater range than ever before on 8.76kHz. Incidentally, the pipe tracing papers I have read suggest that vie= wing the pipe as a conductor with a distributed capacitance to ground= along its length lower frequencies will propagate further as the loss= es from this distributed capacitance to ground will be lower. This tie= s up with my own observation that signal levels at 5.3km distance are= MUCH stronger on 0.838kHz than at 8.76kHz. I have still to try detect= ion with an EFP at 0.838kHz. I really want to get on with my 4m transverter, but this VLF earth= -mode stuff has become rather absorbing and time consuming. Having G6A= LB locally also TXing now has added to the fun and ability to do meani= ngful experiments. By default we seem to have a band-plan for the Dreamer's Band: ear= th-mode around 8.76kHz and radiated around 8.97kHz. 73s Roger G3XBM On 3 February 2011 09:13, Rik Strobbe wrote: Hello Roger, congrats to you and G6ALB for this first succes. At 3km you are still within the near field (at a wavelength of= 33km), so the fact that the EFP works best might indicate that the tr= ansmit antenna acts as an "electrical antenna" rather than as a small= loop. If this is so the signal captured with the EFP will decrease wit= h 40dB/decade, so if you have 20dB SNR at 3km you will reach 0dB SNR= at +/- 10km (assuming same noise level). So if you could find a place= "in the middle of nowhere" (where noise is low) at about 10km you mig= ht be able to copy something. Another thought: how the EFP signal outside the house ? if the= signal if much stronger inside the house this might indicate that the= signal travels through the ground and is "brought up" by the house wi= rering and coupled into the EFP. 73, Rik ON7YD - OR7T ----------------------------------------------------------------------= ---- Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@bla= cksheep.org] namens Roger Lapthorn [rogerlapthorn@gmail.com] Verzonden: donderdag 3 februari 2011 0:39 Aan: rsgb_lf_group@blacksheep.org Onderwerp: LF: More earth-mode tests and a puzzle This evening, during further tests looking for G6ALB's earth-mod= e beacon signal on 8.76kHz, I discovered that best results receiving= at my QTH 3km from Andrew were with a small E-field probe rather than= a loop or earth electrode pair. With the EFP, signals could be detect= ed in my upstairs shack with just a 19inch whip! This suggests that th= e electrostatic component is the dominant one rather than magnetic or= simple potential difference measurable between the 2 earth electrodes= . My basic physics is very rusty and any help clarifying what is going= on would be appreciated. It now means we may have a much easier way= of detecting utilities assisted earth-mode signals at greater ranges= as the positioning of the EFP was far less critical than trying to de= tect signals with a loop lying on the ground. Comments please? 73s Roger G3XBM Via my 2.4GHz handheld (iPod Touch 4g) --=20 g3xbm-qrp.blogspot.com/ www.g3xbm.co.uk www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 ------=_NextPart_000_0020_01CBC39E.9AC87A70 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Chris and LF
This is the point I have been making for some= time,=20 Experimenting with so called earth mode in an urban environment with= a network=20 0f underground pipes and cables of various varieties is a meaningless= excercise.=20
The experiment needs to be conducted in a wide= open rural=20 environment with earth rods used at both the Transmit and Receive=20 end.
de mal/g3kev
 
----- Original Message -----
From:=20 Chris
Sent: Thursday, February 03,= 2011 11:01=20 AM
Subject: Re: LF: RE: More ear= th-mode=20 tests and a puzzle

Hi Roger,
Well, in my humble opinion you're= use of 'earth'=20 mode and so on is inaccurate. I think you have proved this more than= once with=20 your lack of results using your earth rod/house pipes! it seems to= me this is=20 simply conduction through underground pipes and wires. Not totally= unexpected.=20 Genuine earth mode would require you to be away from all pipes etc.= and using=20 two earth rods at both ends.
Whilst this is interesting, I am no= t sure if it=20 is anything new or unexpected, or repeatable in open countryside. Ke= ep up the=20 experimenting though! We're all keen to see what you try next!!
Vy 73,
Chris, G4AYT, Whitstable, Kent, UK.=
----- Original Message -----
Sent: Thursday, February 03= , 2011 10:35=20 AM
Subject: Re: LF: RE: More= earth-mode=20 tests and a puzzle

Hi Rik,

I am pretty certain the signal is fl= owing=20 along the water pipes but that the field around the pipes= is much=20 better detected with the E-field probe than with the loop. The EFP= works=20 very well outside in the street too and is far less critical about= position=20 and orientation. With the loop the signal is strong when clearly= over the=20 pipe work, whereas with the EFP one can, it seems, be almost anywh= ere in the=20 road and house and get a signal. In the house I presume I am picki= ng up the=20 same sort of signal surrounding the pipes within the property.
=
What I=20 do NOT understand is why I get ZERO signal pick-up from G6ALB at= 3km with=20 another earth-electrode set-up at the RX end. One of my ground poi= nts is the=20 copper central heating radiator which connects directly to metal= pipes in=20 the road. I know this as I use the same set-up to launch my own ea= rth-mode=20 signals that can be detected in the roads with a loop out in the= fens=20 >5km away. Logic tells me that if Andrew G6ALB is launching his= signal=20 along pipes from his earth electrode pair then I would get stronge= st signals=20 by also connecting one ground to the metal pipework at the RX end,= but this=20 is definitely not the case as there is absolutely no signal= =20 detectable in QRSS3 by this method, but at least 20dB S/N with the= EFP! Can=20 someone explain what is going on please as I am very=20 baffled!

Tomorrow both G6ALB and I will put our beacons on= (me on=20 8.7608kHz and G6ALB around 8.755kHz) and I will take a trip out in= to the=20 fens with both the loop and the E-field probe to see what I detect= . It is=20 possible that with the EFP I may be able to detect the signal(s)= at greater=20 range than ever before on 8.76kHz.

Incidentally, the pipe= tracing=20 papers I have read suggest that viewing the pipe as a conductor wi= th a=20 distributed capacitance to ground along its length lower frequenci= es will=20 propagate further as the losses from this distributed capacitance= to ground=20 will be lower. This ties up with my own observation that signal le= vels at=20 5.3km distance are MUCH stronger on 0.838kHz than at 8.76kHz. I ha= ve still=20 to try detection with an EFP at 0.838kHz.

I really want to= get on=20 with my 4m transverter, but this VLF earth-mode stuff has become= rather=20 absorbing and time consuming. Having G6ALB locally also TXing now= has added=20 to the fun and ability to do meaningful experiments.

By def= ault we=20 seem to have a band-plan for the Dreamer's Band: earth-mode around= 8.76kHz=20 and radiated around 8.97kHz.

73s
Roger G3XBM

On 3 February 2011 09:13, Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>=20 wrote:
Hello Roger,
 
 
congrats= to you and G6ALB=20 for this first succes.
At= 3km you are=20 still within the near field (at a wavelength of 33km), so the fa= ct that=20 the EFP works best might indicate that the transmit antenna= acts as=20 an "electrical antenna" rather than as a small loop.
If this is so the signal captu= red with the=20 EFP will decrease with 40dB/decade, so if you have 20dB SNR= at 3km=20 you will reach 0dB SNR at +/- 10km (assuming same noise level).= So if you=20 could find a place "in the middle of nowhere" (where noise is lo= w) at=20 about 10km you might be able to copy something.
Another thought: how the= EFP signal=20 outside the house ? if the signal if much stronger inside the ho= use this=20 might indicate that the signal travels through the ground and is= "brought=20 up" by the house wirering and coupled into the EFP.
 
73, Rik  ON7YD - OR7T
 
 
Van: owner-rsgb_lf_group@blacksheep.org [own= er-rsgb_lf_group@blacksheep.org] namens Roger=20 Lapthorn [rogerlapthorn@gmail.com]
Verzonden: donderd= ag=20 3 februari 2011 0:39
Aan: rsgb_lf_group@blac= ksheep.org
Onderwerp: LF:=20 More earth-mode tests and a puzzle

This evening, during further tests looking for G6ALB'= s=20 earth-mode beacon signal on 8.76kHz, I discovered that best resu= lts=20 receiving at my QTH 3km from Andrew were with a small E-field pr= obe rather=20 than a loop or earth electrode pair. With the EFP, signals could= be=20 detected in my upstairs shack with just a 19inch whip! This sugg= ests that=20 the electrostatic component is the dominant one rather than magn= etic or=20 simple potential difference measurable between the 2 earth=20 electrodes. My basic physics is very rusty and= any help=20 clarifying what is going on would be appreciated. It now means= we may have=20 a much easier way of detecting utilities assisted earth-mode sig= nals at=20 greater ranges as the positioning of the EFP was far less critic= al than=20 trying to detect signals with a loop lying on the=20 ground.

Comments please?

73s
Roger G3XBM

Via my 2.4GHz handheld (iPod Touch=20 4g)


=
--=20
g3xbm-qrp.blogspot.com/
www.g3xbm.co.uk
www.youtube.com/user/g= 3xbm
G= 3XBM   GQRP 1678    ISWL=20 G11088
------=_NextPart_000_0020_01CBC39E.9AC87A70--