Return-Path: Received: from mtain-mc05.r1000.mx.aol.com (mtain-mc05.r1000.mx.aol.com [172.29.96.77]) by air-me09.mail.aol.com (v129.4) with ESMTP id MAILINME093-8bc24ca4dc2f68; Thu, 30 Sep 2010 14:51:27 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mc05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 3EA95380000C3; Thu, 30 Sep 2010 14:51:22 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1P1OC3-0008OG-Ip for rs_out_1@blacksheep.org; Thu, 30 Sep 2010 19:49:23 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1P1OBt-0008Ny-8b for rsgb_lf_group@blacksheep.org; Thu, 30 Sep 2010 19:49:13 +0100 Received: from warsl404pip3.highway.telekom.at ([195.3.96.115] helo=email.aon.at) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1P1OBr-0007yX-D0 for rsgb_lf_group@blacksheep.org; Thu, 30 Sep 2010 19:49:14 +0100 Received: (qmail 24510 invoked from network); 30 Sep 2010 18:49:00 -0000 Received: from 91-115-16-153.adsl.highway.telekom.at (HELO [192.168.1.101]) ([91.115.16.153]) (envelope-sender ) by smarthub97.highway.telekom.at (qmail-ldap-1.03) with SMTP for ; 30 Sep 2010 18:48:59 -0000 From: Gerhard Hickl To: rsgb_lf_group@blacksheep.org In-Reply-To: <18AC751DD96A43A3B3B271967EDDF8C2@JimPC> References: <1285607600.1755.7.camel@gerhard-desktop> <18AC751DD96A43A3B3B271967EDDF8C2@JimPC> Date: Thu, 30 Sep 2010 20:48:58 +0200 Message-ID: <1285872538.1476.11.camel@gerhard-desktop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: Re: Aliens on LF ! Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit 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=none 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: 3039ac1d604d4ca4dc2a7449 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Dear Jim ! Thank you for the tip. I really have no idea where it could come from but a motor is a possible source. Until now, I just have seen this signals during the day but that could have to do with the fact that I usually have my grabber running in the TA-window during the night. 73 es gl OE3GHB Gerhard Am Montag, den 27.09.2010, 21:00 +0100 schrieb James Moritz: > Dear Gerhard, LF Group, > > > > > Has anybody an explanation for the kind of signals displayed on my > > grabber sometimes? > > > > I think quite a few people have seen signals like this - one possibility is > switch-mode variable speed drives for AC 3-phase induction motors. The RF is > centred on some harmonic of the switching frequency, the spacing of the > sidebands depends on the motor speed (i.e. the output frequency of the > inverter) ... it would seem quite low in your case. > > Cheers, Jim Moritz > 73 de M0BMU > >