Return-Path: X-Spam-DCC: paranoid 1233; 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, 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 u2GF0jS1021511 for ; Wed, 16 Mar 2016 16:00:45 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1agCrs-0003QG-99 for rs_out_1@blacksheep.org; Wed, 16 Mar 2016 14:56:12 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1agCrr-0003Q7-Uk for rsgb_lf_group@blacksheep.org; Wed, 16 Mar 2016 14:56:11 +0000 Received: from mail-wm0-x22d.google.com ([2a00:1450:400c:c09::22d]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.86) (envelope-from ) id 1agCrp-0004Uq-Hg for rsgb_lf_group@blacksheep.org; Wed, 16 Mar 2016 14:56:10 +0000 Received: by mail-wm0-x22d.google.com with SMTP id p65so193865900wmp.1 for ; Wed, 16 Mar 2016 07:56:09 -0700 (PDT) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:subject:from:in-reply-to:date :content-transfer-encoding:message-id:references:to; bh=IhD+8JwHhCif70NIGhjDdWCtZLjU+pvkh3P5Rvi1FFo=; b=SRRmZ9UIAPKIE6gZb6NkAqPIm+RGb662nI9IooAkg2aTsyY5CwEUVpezh6wRFCnDXS E137fno9HzJKehwqd1PWk0PMDvZo4NI6KEIL6jsQ73cC+scVCoI3jmS9h8FQDmaBFdY4 2TmJ3gHWGvYU1voW9xfKmQQmxW3300rmcqQZfrxs2Tn2R7QlwCKQgGGAw1QLRo81UBed PTbB2zIXdztrlGmHvOeY1Skj2GjuHDTNgYRIhdcuMZK2wn3sJCjPn4BMsY+8GE6U7L98 uj2RnzsBSE0/nfFDNe0SN3XaWjRNeU67Pnvylfd1Npn86EocojUqzXfl6MRfLqoRpwaO h2nA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date :content-transfer-encoding:message-id:references:to; bh=IhD+8JwHhCif70NIGhjDdWCtZLjU+pvkh3P5Rvi1FFo=; b=Im+yEJu2idsUJkuWKXUWr05UBvwcwrb0x6Dq1h6HCIGHNdJh8kFE3bVplobvOJF2DS BD9V5cpNXCh34T/b7TQ5nKPyEeC8Bp38GHdJJVqONPxoMXzid+hw1KG12/EQPHPcm0f8 Hor3yvQo48qKFSwjUWssTKpzBmA37+WAjL11BN1oDs29Y0hoq55Aw4sKZtcBGmsk/SYR K38oDd2o0uDm6DtSwWpjnoM4mm+MRxiikQg84VErdCS3qPN18dXMeT2Jly3gOPQAx+9S E2FJOGHySOnAg60CpvhJAYK14rfukC7LD0e0CcuosDrOu4s5n9x+NeL7vAPozyu0pPaY eCbw== X-Gm-Message-State: AD7BkJIfPvAgRIqi101c6xRDap4ijs1ou+Myl3lW3A7FXkKgNKlyC3Ue1sIM5C2p92shMw== X-Received: by 10.28.134.137 with SMTP id i131mr31870581wmd.62.1458140165776; Wed, 16 Mar 2016 07:56:05 -0700 (PDT) Received: from [192.168.1.101] ([82.98.23.94]) by smtp.gmail.com with ESMTPSA id p189sm26082179wmb.7.2016.03.16.07.56.03 for (version=TLSv1/SSLv3 cipher=OTHER); Wed, 16 Mar 2016 07:56:04 -0700 (PDT) Mime-Version: 1.0 (Mac OS X Mail 9.2 \(3112\)) From: John Rabson In-Reply-To: <8D34CA56489C6DF-2124-1A7BBA@webmail-vm017.sysops.aol.com> Date: Wed, 16 Mar 2016 15:56:00 +0100 Message-Id: <1D7A91E7-DC1B-4641-95BE-FC096D8155E4@gmail.com> References: <8D34C58CF884ECC-1ECC-700FAE@webmail-vd008.sysops.aol.com> <8D34CA56489C6DF-2124-1A7BBA@webmail-vm017.sysops.aol.com> To: rsgb_lf_group@blacksheep.org X-Mailer: Apple Mail (2.3112) X-Scan-Signature: 5c335215f1b3de26d890ee84d49616ce Content-Type: text/plain; charset=us-ascii Subject: Re: LF: 33 Hz QRM 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 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by paranoid.lipkowski.org id u2GF0jS1021511 Status: O X-Status: X-Keywords: X-UID: 7378 I seem to recall that some railway systems use at about 16 2/3 Hz (one third of 50 Hz) for traction. Historically, some systems used about 33 Hz. I read somewhere that on-board power converters on some railway systems work at about 33 Hz/275 V at full load, rising to 50 Hz/415 V when lightly loaded. Can someone say whether my recollections are correct, please? 73 John F5VLF > On 15 Mar 2016, at 08:42, Markus Vester wrote: > > Occasionally I'm getting a new kind of interference with strong 33 Hz spaced lines all over the LF band. Variable RDF colour indicates that it could be emitted from power converters on moving railway vehicles. Several tracks for freight tranis are passing about 400 m south of my QTH. > > Grabber screenshot: http://df6nm.bplaced.net/LF/screenshots/test1603150730.jpg > > Best 73, > Markus (DF6NM) john.rabson07@gmail.com Researching history of RABSON, BLACKSHAW, GAUNTLETT, VERLANDER and ROBSONNE