Return-Path: Received: from mtain-da06.r1000.mx.aol.com (mtain-da06.r1000.mx.aol.com [172.29.64.78]) by air-ma09.mail.aol.com (v129.4) with ESMTP id MAILINMA091-b5344d5446bc4c; Thu, 10 Feb 2011 15:12:44 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-da06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 4C9463800008B; Thu, 10 Feb 2011 15:12:42 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Pncrw-0001My-0q for rs_out_1@blacksheep.org; Thu, 10 Feb 2011 20:12:00 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Pncrv-0001Mp-Fd for rsgb_lf_group@blacksheep.org; Thu, 10 Feb 2011 20:11:59 +0000 Received: from imr-da04.mx.aol.com ([205.188.105.146]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Pncrt-0003Ak-Fe for rsgb_lf_group@blacksheep.org; Thu, 10 Feb 2011 20:11:59 +0000 Received: from mtaout-ma06.r1000.mx.aol.com (mtaout-ma06.r1000.mx.aol.com [172.29.41.6]) by imr-da04.mx.aol.com (8.14.1/8.14.1) with ESMTP id p1AKBsiF028585 for ; Thu, 10 Feb 2011 15:11:54 -0500 Received: from White (nrbg-4dbe708a.pool.mediaWays.net [77.190.112.138]) by mtaout-ma06.r1000.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id 110B1E0000AC for ; Thu, 10 Feb 2011 15:11:51 -0500 (EST) Message-ID: <4828F808B8FF4D81BA3324B23BBDFF2F@White> From: "Markus Vester" To: References: <988315.45122.qm@web28515.mail.ukl.yahoo.com> <4D5436DE.3040602@iup.uni-heidelberg.de> <673772.16865.qm@web28515.mail.ukl.yahoo.com> <67504.51538.qm@web111911.mail.gq1.yahoo.com> Date: Thu, 10 Feb 2011 21:11:56 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 12.0.1606 X-MimeOLE: Produced By Microsoft MimeOLE V12.0.1606 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: Intermod in the receiver - Advice needed Content-Type: multipart/alternative; boundary="----=_NextPart_000_000F_01CBC967.262403A0" 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_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: 3039ac1d404e4d5446ba710f X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_000F_01CBC967.262403A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Daniele, the signal does not really look like one of the RDL types, an= d I also don't think the "copies" are an aliasing artifact. My guess= would be a power converter running at 21 kHz, modulated by 300 Hz fro= m the ripple of a three-phase rectifier. The frequency appears to be= pulled every 0.7 s, perhaps by periodic load changes. All just specul= ation of course... Stefan's grabber has a bag full of 300 Hz harmonics from a nearby tram= , which is presumably running on raw DC. 73, Markus (DF6NM) From: Daniele Tincani=20 Sent: Thursday, February 10, 2011 8:55 PM To: rsgb_lf_group@blacksheep.org=20 Subject: LF: Intermod in the receiver - Advice needed Hello VLF, I attach here a SpecLab screenshot where I have found that multiple co= pies of the same signal are present. The signal at 21100 is probably= genuine RDL, while other copies at about +/- 300Hz look like intermod= products. However, I can't figure out the origin of this 300Hz "spaci= ng", Any hypothesis? Many thanks for your feedback. Regards D. ------=_NextPart_000_000F_01CBC967.262403A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Daniele, the signal does not rea= lly look like=20 one of the RDL types, and I also don't think the "copies" are an alias= ing=20 artifact. My guess would be a power converter running at 21 kHz,= =20 modulated by 300 Hz from the ripple of a three-phase rectifier.= The=20 frequency appears to be pulled every 0.7 s, perhaps by periodic load= changes.=20 All just speculation of course...
 
Stefan's grabber has a bag full= of 300 Hz=20 harmonics from a nearby tram, which is presumably running on = ;raw=20 DC.
 
73, Markus (DF6NM)

Sent: Thursday, February 10, 2011 8:55 PM
Subject: LF: Intermod in the receiver - Advice=20 needed
=

Hello VLF,

 

I attach here a SpecLab screenshot where I have found that multiple= copies of=20 the same signal are present. The signal at 21100 is probably genuine= =20 RDL, while other copies at about +/- 300Hz look like intermod=20 products. However, I can't figure out the origin of&nbs= p;this=20 300Hz "spacing", Any hypothesis?

Many thanks for your feedback.

 

Regards

D.


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