Return-Path: Received: from mtain-ma05.r1000.mx.aol.com (mtain-ma05.r1000.mx.aol.com [172.29.96.13]) by air-ma05.mail.aol.com (v129.4) with ESMTP id MAILINMA053-b5264d4aa67b1af; Thu, 03 Feb 2011 07:58:35 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma05.r1000.mx.aol.com (Internet Inbound) with ESMTP id A971B380000BB; Thu, 3 Feb 2011 07:58:33 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Pkykh-0007sc-Mr for rs_out_1@blacksheep.org; Thu, 03 Feb 2011 12:57:35 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Pkykg-0007sQ-24 for rsgb_lf_group@blacksheep.org; Thu, 03 Feb 2011 12:57:34 +0000 Received: from out1.ip08ir2.opaltelecom.net ([62.24.128.244]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Pkyke-0005NV-1Q for rsgb_lf_group@blacksheep.org; Thu, 03 Feb 2011 12:57:34 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AsoBAK80Sk1Ok86j/2dsb2JhbACCRZAdA4NijmRzvESFWASBYI1Ngm0 X-IronPort-AV: E=Sophos;i="4.60,418,1291593600"; d="scan'208,217";a="478819563" Received: from unknown (HELO xphd97xgq27nyf) ([78.147.206.163]) by out1.ip08ir2.opaltelecom.net with SMTP; 03 Feb 2011 12:57:24 +0000 Message-ID: <003b01cbc3a1$e75f13f0$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <0DF35BB8-9FC4-4A05-A9B9-675D74FEE669@gmail.com> Date: Thu, 3 Feb 2011 12:57:24 -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_0038_01CBC3A1.E7212090" 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: 3039ac1d600d4d4aa67978d4 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_0038_01CBC3A1.E7212090 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Roger The reason you get Zero signal from you home earth mode is because the= transmitted signal is not conducting/inducting into and via the natur= al ground, what you are getting is some sort of conduction via undergr= ound pipes and cables, not what you intended and distorting the resul= ts that you expect. de g3kev ----- 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 but= that the field around the pipes is much better detected with the E-fi= eld 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 G6ALB= 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 viewi= ng the pipe as a conductor with a distributed capacitance to ground al= ong its length lower frequencies will propagate further as the losses= from this distributed capacitance to ground will be lower. This ties= 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-m= ode stuff has become rather absorbing and time consuming. Having G6ALB= locally also TXing now has added to the fun and ability to do meaning= ful experiments. By default we seem to have a band-plan for the Dreamer's Band: earth= -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 33k= m), so the fact that the EFP works best might indicate that the transm= it antenna acts as an "electrical antenna" rather than as a small loop= . If this is so the signal captured with the EFP will decrease with= 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 "i= n the middle of nowhere" (where noise is low) at about 10km you might= be able to copy something. Another thought: how the EFP signal outside the house ? if the sig= nal if much stronger inside the house this might indicate that the sig= nal travels through the ground and is "brought up" by the house wireri= ng and coupled into the EFP. 73, Rik ON7YD - OR7T ----------------------------------------------------------------------= ------ Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@black= sheep.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-mode= 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 detected= in my upstairs shack with just a 19inch whip! This suggests that the= 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_0038_01CBC3A1.E7212090 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Roger
The reason you get Zero signal from you home= earth mode is=20 because the transmitted signal is not conducting/inducting into and vi= a the=20 natural ground, what you are getting is some sort of conduction via un= derground=20 pipes and cables, not what you intended and distorting  the resul= ts that=20 you expect.
de g3kev
 
----- Original Message -----
Sent: Thursday, February 03,= 2011 10:35=20 AM
Subject: Re: LF: RE: More ear= th-mode=20 tests and a puzzle

Hi Rik,

I am pretty certain the signal is flow= ing along=20 the water pipes but that the field around the pipes is much= better=20 detected with the E-field probe than with the loop. The EFP works ve= ry well=20 outside in the street too and is far less critical about position an= d=20 orientation. With the loop the signal is strong when clearly over th= e pipe=20 work, whereas with the EFP one can, it seems, be almost anywhere in= the road=20 and house and get a signal. In the house I presume I am picking up= the same=20 sort of signal surrounding the pipes within the property.

Wha= t I do NOT=20 understand is why I get ZERO signal pick-up from G6ALB at 3km with= another=20 earth-electrode set-up at the RX end. One of my ground points is the= copper=20 central heating radiator which connects directly to metal pipes in= the road. I=20 know this as I use the same set-up to launch my own earth-mode signa= ls that=20 can be detected in the roads with a loop out in the fens >5km awa= y. Logic=20 tells me that if Andrew G6ALB is launching his signal along pipes fr= om his=20 earth electrode pair then I would get strongest signals by also conn= ecting one=20 ground to the metal pipework at the RX end, but this is definitely= not=20 the case as there is absolutely no signal detectable in QRSS3 by thi= s method,=20 but at least 20dB S/N with the EFP! Can someone explain what is goin= g on=20 please as I am very baffled!

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

Incidentally,= the pipe=20 tracing papers I have read suggest that viewing the pipe as a conduc= tor with a=20 distributed capacitance to ground along its length lower frequencies= 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 leve= ls at=20 5.3km distance are MUCH stronger on 0.838kHz than at 8.76kHz. I have= still to=20 try detection with an EFP at 0.838kHz.

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

By default we seem to= have a=20 band-plan for the Dreamer's Band: earth-mode around 8.76kHz and radi= ated=20 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 3k= m you are still=20 within the near field (at a wavelength of 33km), so the fact that= the EFP=20 works best might indicate that the transmit antenna acts as= an=20 "electrical antenna" rather than as a small loop.
If this is so the signal capture= d with the EFP=20 will decrease with 40dB/decade, so if you have 20dB SNR at 3k= m you will=20 reach 0dB SNR at +/- 10km (assuming same noise level). So if you= could find=20 a place "in the middle of nowhere" (where noise is low) at about= 10km you=20 might be able to copy something.
Another thought: how the EF= P signal=20 outside the house ? if the signal if much stronger inside the hous= e 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 [owner-rsgb_lf= _group@blacksheep.org] namens Roger Lapthorn=20 [= rogerlapthorn@gmail.com]
Verzonden: donderdag 3=20 februari 2011 0:39
Aan: rsgb_lf_group@blacksheep.o= rg
Onderwerp: LF: More=20 earth-mode tests and a puzzle

This evening, during further tests looking for G6ALB's= earth-mode=20 beacon signal on 8.76kHz, I discovered that best results receiving= at my QTH=20 3km from Andrew were with a small E-field probe rather than a loop= or earth=20 electrode pair. With the EFP, signals could be detected in my upst= airs shack=20 with just a 19inch whip! This suggests that the electrostatic comp= onent is=20 the dominant one rather than magnetic or simple potential differen= ce=20 measurable between the 2 earth electrodes. My ba= sic=20 physics is very rusty and any help clarifying what is going on wou= ld be=20 appreciated. It now means we may have a much easier way of detecti= ng=20 utilities assisted earth-mode signals at greater ranges as the pos= itioning=20 of the EFP was far less critical than trying to detect signals wit= h a loop=20 lying on the ground.

Comments please?

73s
Roger G3XBM

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


--
g3xbm-qrp.blogspot.com/
www.g3xbm.co.uk
www.youtube.com/user/g3xb= m
G3XBM&= nbsp;  GQRP 1678    ISWL=20 G11088
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