Return-Path: X-Spam-DCC: paranoid 1181; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_MESSAGE,SPF_PASS autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u2TAPJB3031796 for ; Tue, 29 Mar 2016 12:25:19 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1akqkj-0000yC-T4 for rs_out_1@blacksheep.org; Tue, 29 Mar 2016 11:20:01 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1akqki-0000xy-V8 for rsgb_lf_group@blacksheep.org; Tue, 29 Mar 2016 11:20:00 +0100 Received: from nm30-vm3.bullet.mail.ir2.yahoo.com ([212.82.97.81]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.86) (envelope-from ) id 1akqkg-0007Rb-P6 for rsgb_lf_group@blacksheep.org; Tue, 29 Mar 2016 11:19:59 +0100 X-DKIM-Result: Domain=yahoo.co.uk Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.co.uk; s=s2048; t=1459246797; bh=1TdKWIpHs4P9UvWHXIO194nJLJYmrallQcPehAQJX5s=; h=Date:From:Reply-To:To:In-Reply-To:References:Subject:From:Subject; b=gTFlsRgyeRB5i+CCcLf0GKtKw0eGxk6T7Wg1d6F2HHbv+VGVc002wJr/0VDsO/56NUFJRacUbL6y+LWEqC/Okvcrv+ZZDscX+bFg1chZp+3QhKDmo7kLUI9iPcOoxjO3GMit9sYiquQI94m4aqvpB84iXXJdt1IHijPGnpL2KNW2juE31PkTRvAU1eNgGEnCn2S+bfIMXDO8IQu/GSd3XAy7JzlC+/pJY7YH/pXZYyIzDq+BJSLKWwljam0+YanOOJY62KkX+rqP9afMIyLxdxPoXYiMB2w9v2BsNIeXzTfTFUeltbF04DTiq357WoW5F9dHenabnBVZnas3poEwqQ== Received: from [212.82.98.63] by nm30.bullet.mail.ir2.yahoo.com with NNFMP; 29 Mar 2016 10:19:57 -0000 Received: from [212.82.98.99] by tm16.bullet.mail.ir2.yahoo.com with NNFMP; 29 Mar 2016 10:19:57 -0000 Received: from [127.0.0.1] by omp1036.mail.ir2.yahoo.com with NNFMP; 29 Mar 2016 10:19:57 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 388327.60796.bm@omp1036.mail.ir2.yahoo.com X-YMail-OSG: VqK2XVoVM1kt268LVOH06dGWw4Sfb8cBtrCu_4lBnG8rSUYQUUtqQFTMz3NhDQ9 Wdz8d5mXVz19zsDrfRWwdGIT8OJvLt.cfSapcgKTPwu15jvMEXmB2RkaJsok3ZrvTnI585QZKai6 Cd1TJ4C7ZjIy2YtbEPpo9MP436SIkIo8QR9.y7gEeHUBfPhGr.d3TD3a2TA1SofgZj9THNIjG_lV zH4KryKDYGEQLqQYma66ERbjx1ZOErrzuQXBq1JobTJ4iu32u3j1aV8v00sSiiLlJP8JiwzkZJdo HL6bxs2NvYgOk6d_tm.R8RUpXQYAY_AdeOkiNx9EZatpHOIDcNuoGZFJXcykObqaDtxi_zBYsEwi KWTPSyJaz1G2xEh1Ojbj016uTmerPwY9cOqZa2P0aMlb9B65abyMeKhVbFJvBSfjmaJwN8ZgLZFX E83KE2dRFCbn.ZyzfnNpYinZev76_nW1M3zqWLBFW5BrMEyws0A9lTkmP2VZf6MqunAEq7ipna6k 26WtxXcCKI.A4SO.FfW7xwe5s4CAvCGmLT33Nfn5J02f4BO6CIyoe2dHt7kuanbruFNj5rClpcMt ne3wIy8798HkbWMFyXReV3hKd.nYLiaIjQS3V0IY8ELB6famL9CXDIjbIa6rELT7SVicXPj0dTK2 F0RfxKaVjXrtCFK0sr4dEF69FZsGYq04i_OwG0ZQ- Received: by 217.12.9.8; Tue, 29 Mar 2016 10:19:56 +0000 Date: Tue, 29 Mar 2016 10:19:01 +0000 (UTC) From: David Hine To: "rsgb_lf_group@blacksheep.org" Message-ID: <1402595104.2741657.1459246741335.JavaMail.yahoo@mail.yahoo.com> In-Reply-To: <56FA2A98.6030005@tele2.se> References: <56FA2A98.6030005@tele2.se> MIME-Version: 1.0 X-Scan-Signature: c1dcf088149efa0360827745859da381 Subject: Re: LF: 33 Hz QRM Content-Type: multipart/alternative; boundary="----=_Part_2741656_195073405.1459246741330" 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 7508 ------=_Part_2741656_195073405.1459246741330 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi, A very interesting article. The London Underground (Metro) uses a low v= oltage=C2=A04 rail DC system. The 2 'live rails are=C2=A0 balanced + and - = with regard to the running rails. This system is a 'throw-back' from the da= ys of DC motors and this system reduces corrosion causing currents to flow = in the running rails and other track equipment. There is a lot to be said f= or the self contained diesel units that require no external power supplies = with all that infrastructure. Imagine how useless the electric system would= be in times of extreme weather or disasters, man made or natural.=C2=A0The= same applies to modern digital radio communications (with all its necessar= y=C2=A0infrastructure and thousands of tiny transmitters) when compared to = the old Long Wave AM broadcasting, where a single large transmitter covers = a whole continent.=C2=A0Nowadays 'progress' always results in over-complica= ted and 'fragile' systems that fail too easily=C2=A0when 'nasty=C2=A0things= happen'.With very kind regards, Dave. From: Johan Bodin To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, 29 March 2016, 8:11 Subject: Re: LF: 33 Hz QRM =20 That problem can be solved by using a return line and booster transformers= that minimises current leakage into surrounding earth: =20 https://library.e.abb.com/public/f1200714de5086c585257d7300287357/1LFI2026%= 20special%20power%20transformers%20for%20railway%20-%20brochure%20EN.pdf =20 73 de Johan SM6LKM =20 Den 2016-03-17 kl. 15:18, skrev Andy Talbot: =20 Is that to minimise skin loss in steel track ?=20 UK Third rail is, of course, DC, and I once spent an idle moment calculat= ing the loss if 50Hz AC were to be used with magnetic iron conductors.=C2= =A0 I think I came to the conclusion a 1MW train could probably travel a fe= w hundred metres before it lost its power supply.=20 andy=C2=A0 G4JNT =20 On 17 March 2016 at 13:21, Johan Bodin wrote: =20 Railway QRG is 16 2/3 Hz in Sweden too. =20 73 de Johan SM6LKM =20 John Rabson wrote: =20 I seem to recall that some railway systems use at about 16 2/3 Hz (one thir= d of 50 Hz) for traction. =20 ... =20 Can someone say whether my recollections are correct, please? =20 73 John F5VLF =20 =20 =20 =20 =20 =20 =20 ------=_Part_2741656_195073405.1459246741330 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Hi, A very interesting a= rticle. The London Underground (Metro) uses a low voltage 4 rail DC sy= stem. The 2 'live rails are  balanced + and - with regard to the runni= ng rails. This system is a 'throw-back' from the days of DC motors and this= system reduces corrosion causing currents to flow in the running rails and= other track equipment. There is a lot to be said for the self contained di= esel units that require no external power supplies with all that infrastruc= ture. Imagine how useless the electric system would be in times of extreme = weather or disasters, man made or natural.
 The same applies to modern digital radio communications (with all= its necessary infrastructure and thousands of tiny transmitters) when= compared to the old Long Wave AM broadcasting, where a single large transm= itter covers a whole continent. Nowadays 'progress' always results in = over-complicated and 'fragile' systems that fail too easily when 'nast= y things happen'.
With very kind r= egards, Dave.


From: Johan Bodin <jhbodin@te= le2.se>
To: rsgb_lf= _group@blacksheep.org
Sent: Tuesday, 29 March 2016, 8:11
Subject: Re: LF: 33 Hz QRM

That problem can be solved by using a return line and booster transformers that minimises current leakage into surrounding earth:

h= ttps://library.e.abb.com/public/f1200714de5086c585257d7300287357/1LFI2026%2= 0special%20power%20transformers%20for%20railway%20-%20brochure%20EN.pdf=

73 de
Johan SM6LKM

Den 2016-03-17 kl. 15:18, s= krev Andy Talbot:
=
Is that to minimise skin loss in steel track ?

UK Third rail is, of course, DC, and I once spent an idle moment calculating the loss if 50Hz AC were to be used with magnetic iron conductors.  I think I came to the conclusion = a 1MW train could probably travel a few hundred metres before it lost its power supply.

andy  G4JNT

On 17 March 2016 at 13:21, = Johan Bodin <jhbodin@tele2.se> wrote:
Railway QRG is 16 2/3 Hz in Sweden too.

73 de Johan SM6LKM

John Rabson wrote:
I seem to recall that some railway systems use at about 16 2/3 Hz (one third of 50 Hz) for traction.
...
Can someone say whether my recollections are correct, please?

73 John F5VLF





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