Return-Path: Received: from mtain-mb05.r1000.mx.aol.com (mtain-mb05.r1000.mx.aol.com [172.29.96.25]) by air-dc09.mail.aol.com (v127_r1.1) with ESMTP id MAILINDC092-862d4b838d49377; Tue, 23 Feb 2010 03:09:45 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mb05.r1000.mx.aol.com (Internet Inbound) with ESMTP id C629C380000E9; Tue, 23 Feb 2010 03:09:43 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NjpoQ-0007eV-79 for rs_out_1@blacksheep.org; Tue, 23 Feb 2010 08:08:10 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NjpoP-0007eM-KJ for rsgb_lf_group@blacksheep.org; Tue, 23 Feb 2010 08:08:09 +0000 Received: from mhost02h.leeds.ac.uk ([129.11.77.151]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NjpoM-0000QK-TM for rsgb_lf_group@blacksheep.org; Tue, 23 Feb 2010 08:08:09 +0000 Received: from APOLLO2.ds.leeds.ac.uk (apollo2.leeds.ac.uk [129.11.5.5]) by mhost02h.leeds.ac.uk (8.14.3/8.14.3) with ESMTP id o1N880vE010693 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT) for ; Tue, 23 Feb 2010 08:08:00 GMT Received: from HERMES8.ds.leeds.ac.uk ([fe80::39ce:23e:d0b5:7e24]) by APOLLO2.ds.leeds.ac.uk ([129.11.5.5]) with mapi; Tue, 23 Feb 2010 08:07:59 +0000 From: Chris Trayner To: "rsgb_lf_group@blacksheep.org" Date: Tue, 23 Feb 2010 08:07:58 +0000 Thread-Topic: AW: LF: AW: Beaconing on 8.79 kHz in QRSS Thread-Index: Acq0X1BXicQuTKkDTQqpXSAdQVpACw== Message-ID: References: In-Reply-To: Accept-Language: en-US, en-GB Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US, en-GB MIME-Version: 1.0 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: AW: LF: AW: Beaconing on 8.79 kHz in QRSS Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=TO_ADDRESS_EQ_REAL 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: 3039ac1d60194b838d471c31 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) Hi Jean-Louis and others, On 2010 Feb 22, at 11:59, wrote: > Hi Rik > =20 > In a french book called "Poste 85" describing the beginning of the elect= ronics era during WW1 (telephone, radio, gonio, etc) , it is said that it= was possible to listen to enemy telephone conversations by putting some= rods in the ground and connecting them to a 3 triodes amplifier (the retu= rn audio ground current of the wire telephones were strong enough to allow= conversations spying)=20 If this interests you, there's another book on the same subject: Listening= In, by Ernest H. Hinrichs, 148 pp., pub. White Mane Books, Shippensburg,= PA, USA (1996). Hinrichs was a US national of German extraction, fluent in German, and ser= ved with the US Army in WWI intercepting German front-line communications.= His work was with ground current communications, trying to pick up stray= signals from German field telephones. The book describes his WWI experien= ces and gives a reasonable amount of technical detail of the equipment.=20 I seem to recall an assessment of it from the electronics point of view in= the Cave Radio and Electronics Group Journal, but I forget when. I think= John F5VLF wrote it; if you're interested, you could ask him. There are over a dozen copies on AbeBooks, with prices starting at under= EUR 4. 73, Chris G4OKW ----------------------- Dr Chris Trayner School of Electronic & Electrical Engineering, The University of Leeds, Leeds LS2 9JT, United Kingdom Tel: +44 113 34 32053 Fax: +44 113 34 32032