Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dd01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 01694380000B0; Mon, 15 Aug 2011 15:20:50 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Qt2hZ-0007V7-6N for rs_out_1@blacksheep.org; Mon, 15 Aug 2011 20:19:57 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Qt2hY-0007Uw-Eq for rsgb_lf_group@blacksheep.org; Mon, 15 Aug 2011 20:19:56 +0100 Received: from filter02.i-online.fr ([195.200.78.9]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Qt2hW-0001dx-K5 for rsgb_lf_group@blacksheep.org; Mon, 15 Aug 2011 20:19:56 +0100 Received: from smtp.qtxt.dns-iol.com ([195.200.78.13]) by filter02.i-online.fr (IceWarp 10.2.2) with ESMTP (SSL) id YBH60049 for ; Mon, 15 Aug 2011 21:18:49 +0200 Received: (qmail 30958 invoked by uid 507); 15 Aug 2011 21:19:40 +0200 Received: from unknown (HELO ?192.168.1.101?) (john.rabson@numeo.fr@217.67.155.178) by smtp.qtxt.dns-iol.com with SMTP; 15 Aug 2011 21:19:40 +0200 Mime-Version: 1.0 (Apple Message framework v1084) From: John Rabson X-Priority: 3 In-Reply-To: <002e01cc5b74$8fe894a0$0401a8c0@xphd97xgq27nyf> Date: Mon, 15 Aug 2011 21:19:46 +0200 Message-Id: <4610CAD0-79ED-4181-8688-940647093ED2@numeo.fr> References: <8F12A13F-4174-4C0F-8916-1543A69C2E65@gmail.com><17BB4B3F-F338-4973-8F87-BD710C9C1539@numeo.fr> <002e01cc5b74$8fe894a0$0401a8c0@xphd97xgq27nyf> To: rsgb_lf_group@blacksheep.org X-Mailer: Apple Mail (2.1084) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: Ferrite rods Content-Type: multipart/alternative; boundary=Apple-Mail-39-121337866 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_40_50, 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-SCORE: 1:2:471851232:93952408 X-AOL-SCOLL-URL_COUNT: 1 x-aol-sid: 3039ac1d408d4e4971924802 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --Apple-Mail-39-121337866 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-1 CREGies do! John F5VLF On 15 Aug 2011, at 19:55CEST, mal hamilton wrote: > Who wants sub surface !!!!!!!!!! Stay above ground as long as = possible!! > G3KEV > =20 > ----- Original Message ----- > From: Steve, g4vbd > To: rsgb_lf_group@blacksheep.org > Sent: Monday, August 15, 2011 6:45 PM > Subject: Re: LF: Ferrite rods >=20 > Guys > Its =A349.00 from this web site > =20 > = http://www.lulu.com/product/paperback/channel-characterisation-and-system-= design-for-sub-surface-communications/11253100 > =20 > too expensive for me - but if you find a pdf then I'd be interested as = well > Found this though > Electrode Contact Impedance Measurement in Through-The-Earth = Communications >=20 > =20 > http://dcis2009.unizar.es/FILES/CR2/p30.pdf > =20 > regards > Steve, g4vbd >=20 >=20 > =20 > On Mon, Aug 15, 2011 at 12:02 PM, Roger Lapthorn = wrote: > Is this PhD document publically available as a PDF John? >=20 > 73s > Roger G3XBM >=20 >=20 > On 15 August 2011 11:26, John Rabson wrote: > There is an extensive discussion of ferrite rod antennas in Chapter 4 = of: >=20 > Gibson, David (2004) Channel Characterisation and System Design = for Sub-Surface Communications PhD thesis, Leeds University 2004. >=20 > John > F5VLF >=20 > On 15 Aug 2011, at 09:46CEST, Roger Lapthorn wrote: >=20 > > Although I've little experience of ferrite rods on LF receive I did = wind my 600uH 500kHz ATU loading coil for my 5w transverter on one. = With just a 5m top loaded vertical it worked well without saturation = problems when sitting on the bedroom table. At QRP it is less lossy as = less wire is needed. > > > > People have successfully engineered (single turn I think) ferrite = rods as TX antennas for 10MHz QRPp WSPR. Somewhere I have some = information on this. As long as saturation is avoided there is some = mileage for HF TX applications in very compact QRP stations. > > > > Worth some experiments on LF receive Stefan. > > > > 73s > > Roger G3XBM > > > > Via my iPod Touch 4g 2.4GHz handheld. > > >=20 >=20 >=20 >=20 >=20 > --=20 > http://g3xbm-qrp.blogspot.com/ > http://www.g3xbm.co.uk > http://www.youtube.com/user/g3xbm > https://sites.google.com/site/sub9khz/ >=20 >=20 >=20 --Apple-Mail-39-121337866 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=iso-8859-1 CREGies do!
John = F5VLF

On 15 Aug 2011, at 19:55CEST, mal hamilton = wrote:

Who wants sub surface = !!!!!!!!!! Stay above ground as long as = possible!!
G3KEV
 
----- Original Message = -----

 
too = expensive for me - but if you find a pdf then I'd be interested as = well
Found this though

Electrode Contact Impedance = Measurement in Through-The-Earth = Communications

 
 
regards
St= eve, g4vbd


 
On = Mon, Aug 15, 2011 at 12:02 PM, Roger Lapthorn <rogerlapthorn@gmail.com> wrote:
Is this PhD document publically available as = a PDF John?

73s
Roger G3XBM


On 15 August 2011 11:26, = John Rabson <john.rabson@numeo.fr> wrote:
There is an extensive discussion of ferrite = rod antennas in Chapter 4 of:

       Gibson, = David (2004) Channel Characterisation and System Design for Sub-Surface = Communications PhD thesis, Leeds University = 2004.

John
F5VLF

On 15 Aug 2011, = at 09:46CEST, Roger Lapthorn wrote:

> Although I've little = experience of ferrite rods on LF receive I did wind my 600uH 500kHz ATU = loading coil for my 5w transverter on one.  With just a 5m top = loaded vertical it worked well without saturation problems when =  sitting on the bedroom table. At QRP it is less lossy as less wire = is needed.
>
> People have successfully engineered (single = turn I think) ferrite rods as TX antennas for 10MHz QRPp WSPR. Somewhere = I have some information on this. As long as saturation is avoided there = is some mileage for HF TX applications in very compact QRP = stations.
>
> Worth some experiments on LF receive = Stefan.
>
> 73s
> Roger G3XBM
>
> Via my = iPod Touch 4g 2.4GHz = handheld.
>





-- 
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
https://sites.google.com/site/sub9khz/




= --Apple-Mail-39-121337866--