Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mg05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 3E6A7380000A3; Tue, 8 Jan 2013 16:05:23 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1TsgLG-0001um-9h for rs_out_1@blacksheep.org; Tue, 08 Jan 2013 21:04:14 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1TsgLF-0001ud-Kv for rsgb_lf_group@blacksheep.org; Tue, 08 Jan 2013 21:04:13 +0000 Received: from mk-filter-2-a-1.mail.tiscali.co.uk ([212.74.100.53] helo=mk-filter-2-a-1.mail.uk.tiscali.com) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1TsgLD-00037O-4l for rsgb_lf_group@blacksheep.org; Tue, 08 Jan 2013 21:04:12 +0000 X-Trace: 834473143/mk-filter-2.mail.uk.tiscali.com/B2C/$THROTTLED_DYNAMIC/b2c-CUSTOMER-DYNAMIC-IP/88.104.44.203/None/g4wgt@tiscali.co.uk X-SBRS: None X-RemoteIP: 88.104.44.203 X-IP-MAIL-FROM: g4wgt@tiscali.co.uk X-SMTP-AUTH: X-Originating-Country: GB/UNITED KINGDOM X-MUA: Microsoft Windows Mail 6.0.6002.18197Produced By Microsoft MimeOLE V6.1.7601.17609 X-IP-BHB: Once X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AjYFAMSI7FBYaCzL/2dsb2JhbABEpXwDhHuSYxdzgh4BAQUITgIsAQQFAwMRBAEBCiUzBhYIBhMICYd0AxMIqXiBdgKLMgSLaIRMYQOILJM4inGCdA X-IronPort-AV: E=Sophos;i="4.84,434,1355097600"; d="scan'208,217";a="834473143" Received: from 88-104-44-203.dynamic.dsl.as9105.com (HELO GaryAsus) ([88.104.44.203]) by smtp.tiscali.co.uk with SMTP; 08 Jan 2013 21:03:50 +0000 Message-ID: <33B9650C39E546EBAFE3BFA53CAB7F26@GaryAsus> From: "Gary - G4WGT" To: References: <428AD1894D5E4BA78368C439F5CB7A12@GaryAsus> In-Reply-To: Date: Tue, 8 Jan 2013 21:03:49 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6002.18197 X-MimeOLE: Produced By Microsoft MimeOLE V6.1.7601.17609 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hi Marcus, Thank you for your comment.... I have not seen a signal derived from a motor quite as stable as this one is, but since you qualify that with your description you may be correct. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [212.74.100.53 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (g4wgt[at]tiscali.co.uk) -0.0 SPF_HELO_PASS SPF: HELO matches SPF record -0.0 SPF_PASS SPF: sender matches SPF record 0.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: f50ffa2d596e60b11ae43c4854906bce Subject: LF: Re: Re: Strange signal Content-Type: multipart/alternative; boundary="----=_NextPart_000_001F_01CDEDE3.A823CCD0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,HTML_MESSAGE, MISSING_OUTLOOK_NAME 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: 3039ac1d60cd50ec8a124360 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_001F_01CDEDE3.A823CCD0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Marcus, Thank you for your comment.... I have not seen a signal derived from a motor quite as stable as this = one is, but since you qualify that with your description you may be = correct. When I have monitored VLF I have seen our laundry washing machine = operate & it is a very unstable signal. Of course ours is quite old now = & many modern machines have very complicated control systems & direct = drive motors etc. Interesting observation.....I have looked back at my recent captures & = note that the "signal" on 474.750 kHz has only appeared since 1430z = today during & after our next door neighbour has had a new central = heating boiler installed. You may have noticed the other rubbish in the upper part of the display = on the full screen shot, I suspect a neighbour has recently purchased a = new TV or similar digital equipment. 73, Gary - G4WGT. ----- Original Message -----=20 From: Markus Vester=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, January 08, 2013 8:27 PM Subject: LF: Re: Strange signal Hi Gary, reminds me of those pretty little asterisk- or spider-shaped artifacts = which occasionally appeared on MF and were discussed on this list a = couple of years ago. I think the most plausible explanation we found was = the acceleration of a brushless synchronous motor. The chopper = fundamental frequency might be generated by a digital PWM controller = having a stable crystal clock, and the variable sidebands are due to the = rotor angle rate dependent modulation.=20 Perhaps this one is similar? Maybe a modern laundry machine or = dishwasher coming up to speed, overshooting a while, and then settling = on the preset rpm rate.=20 Best 73, Markus (DF6NM) ----- Original Message -----=20 From: Gary - G4WGT=20 To: LF Group=20 Cc: rsgb_lf_group@yahoogroups.co.uk=20 Sent: Tuesday, January 08, 2013 8:26 PM Subject: LF: Strange signal Hi All, I am seeing a strange signal centered on 474.750 kHz. It is = periodically visible & audible on my grabber system & my JRC NRD-345. = there appears to be no data, just continuous tones. Both systems using = separate antennas. I have placed a capture on Dropbox of the grabber image & you can see = the end of a previous period & the start of a new one. The signal = pattern starts with a bulge at the beginning but just shuts off at the = end. https://dl.dropbox.com/u/15990181/472-479-1301081910.jpg I have also placed a capture from the JRC Rx with SpecLab running at = QRS01. https://dl.dropbox.com/u/15990181/capt1301081909.jpg Any ideas or knowledge of this signal ? 73, Gary - G4WGT. ------=_NextPart_000_001F_01CDEDE3.A823CCD0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Marcus,
 
Thank you for your = comment....
 
I have not seen a signal derived from a = motor quite=20 as stable as this one is, but since you qualify that with your = description you=20 may be correct.
 
When I have monitored VLF I have seen = our=20 laundry washing machine operate & it is a very unstable = signal. Of=20 course ours is quite old now & many modern machines have very = complicated=20 control systems & direct drive motors etc.
 
Interesting observation.....I have = looked back at=20 my recent captures & note that the "signal" on 474.750 kHz has only = appeared=20 since 1430z today during & after our next door neighbour has had a = new=20 central heating boiler installed.
 
You may have noticed the other rubbish = in the upper=20 part of the display on the full screen shot, I suspect a neighbour has = recently=20 purchased a new TV or similar digital equipment.
 
73,
 
Gary - G4WGT.
 
----- Original Message -----
From:=20 Markus=20 Vester
Sent: Tuesday, January 08, 2013 = 8:27=20 PM
Subject: LF: Re: Strange = signal

Hi Gary,
 
reminds me of those pretty = little asterisk-=20 or spider-shaped artifacts which occasionally appeared on MF = and=20 were discussed on this list a couple of years ago. I think the most = plausible=20 explanation we found was the acceleration of a brushless = synchronous=20 motor. The chopper fundamental frequency might be generated by a = digital PWM=20 controller having a stable crystal clock, and the variable = sidebands=20 are due to the rotor angle rate dependent modulation. =
 
Perhaps this one is similar? = Maybe a modern=20 laundry machine or dishwasher coming up to speed, overshooting a = while,=20 and then settling on the preset rpm rate. 
 
Best 73,
Markus (DF6NM)
 
 
----- Original Message -----=20
From: Gary - = G4WGT=20
Sent: Tuesday, January 08, 2013 8:26 PM
Subject: LF: Strange signal

Hi All,
 
I am seeing a strange signal = centered on=20 474.750 kHz. It is periodically visible & audible on my = grabber=20 system & my JRC NRD-345. there appears to be no data, just = continuous=20 tones. Both systems using separate antennas.
 
I have placed a capture on Dropbox of = the grabber=20 image & you can see the end of a previous period & the start = of a new=20 one. The signal pattern starts with a bulge at the beginning but just = shuts=20 off at the end.
 
https:/= /dl.dropbox.com/u/15990181/472-479-1301081910.jpg
 
I have also placed a capture from the = JRC Rx with=20 SpecLab running at QRS01.
 
https://dl.= dropbox.com/u/15990181/capt1301081909.jpg
 
Any ideas or knowledge of this signal = ?
 
73,
 
Gary - G4WGT.
 
 
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