Return-Path: Received: from imd-db01.r1000.mx.aol.com (imd-db01.r1000.mx.aol.com [172.29.48.1]) by air-db10.mail.aol.com (v129.4) with ESMTP id MAILINDB103-864c4d6ffa79251; Thu, 03 Mar 2011 15:30:49 -0500 Received: from mtain-mb04.r1000.mx.aol.com (mtain-mb04.r1000.mx.aol.com [172.29.96.24]) by imd-db01.r1000.mx.aol.com (Inbound Mail Deferral) with ESMTP id D9C70702BD1D9; Thu, 3 Mar 2011 15:21:37 -0500 (EST) Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mb04.r1000.mx.aol.com (Internet Inbound) with ESMTP id 0AC4D38004E71; Thu, 3 Mar 2011 15:20:25 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PvEzs-0007P7-2K for rs_out_1@blacksheep.org; Thu, 03 Mar 2011 20:19:40 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PvEzr-0007Oy-Kf for rsgb_lf_group@blacksheep.org; Thu, 03 Mar 2011 20:19:39 +0000 Received: from imr-da05.mx.aol.com ([205.188.105.147]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PvEzp-0003wK-2n for rsgb_lf_group@blacksheep.org; Thu, 03 Mar 2011 20:19:39 +0000 Received: from mtaout-da04.r1000.mx.aol.com (mtaout-da04.r1000.mx.aol.com [172.29.51.132]) by imr-da05.mx.aol.com (8.14.1/8.14.1) with ESMTP id p23KJRT1016126 for ; Thu, 3 Mar 2011 15:19:27 -0500 Received: from White (nrbg-4dbf9fac.pool.mediaWays.net [77.191.159.172]) by mtaout-da04.r1000.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id 51C4CE0000B8 for ; Thu, 3 Mar 2011 15:19:24 -0500 (EST) Message-ID: From: "Markus Vester" To: References: <6C9E0C3D501744C99E11539B7AFCB120@IBM7FFA209F07C> Date: Thu, 3 Mar 2011 21:19:43 +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: Topband Test Content-Type: multipart/alternative; boundary="----=_NextPart_000_003E_01CBD9E8.B6F487B0" 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: 3039ac1d60184d6ff80950ce X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_003E_01CBD9E8.B6F487B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Chris, thanks for sharing this unusual observation. >From your screenshot, the split was up to about 0.35 Hz, or 0.2 ppm of= 1.8 MHz. Interpreted as Doppler, a reflector would have to move at le= ast 30m/s radially from your baseline. This seems a bit fast for an io= nospheric day-to-night shift. Another possible explanation could be airplane scatter. Large airliner= s are known to have a large radar cross section at HF. Seeing that on= 160 m may seem extreme, but considering the wingspan of an A-380 (80= m), half-wave resonant scattering is a very real possibility. The dow= nward slope of the Doppler shifted frequency would also be indicative= of an object passing by at constant linear velocity. Best 73, Markus (DF6NM) From: Chris=20 Sent: Thursday, March 03, 2011 7:55 PM To: RSGB LF Group=20 Subject: LF: Topband Test Hi All, Yesterday evening Pete, M0FMT, transmitted QRSS on topband for a test.= An unexpected effect was noticed with the trace splitting in two. Not= hing new or 'earth shattering' I expect, but new to us and worthy of= further experimentation. See the result and conclusion on my website http://qsl.net/g4ayt on th= e bottom of page 1. I have never seen this effect on 137, even with quite strong audible= signals, maybe others have. Vy 73, Chris, G4AYT, Whitstable, UK. ------=_NextPart_000_003E_01CBD9E8.B6F487B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Chris, thanks for sharing this unu= sual=20 observation.
 
From your screenshot, the split was= up to about=20 0.35 Hz, or 0.2 ppm of 1.8 MHz. Interpreted as Doppler, a re= flector=20 would have to move at least 30m/s radially from your baseline. Th= is seems a=20 bit fast for an ionospheric day-to-night shift.
 
Another possible explanation could be= airplane=20 scatter. Large airliners are known to have a large radar cro= ss section=20 at HF. Seeing that on 160 m may seem extreme, but considerin= g the=20 wingspan of an A-380 (80 m), half-wave resonant scattering= is a very=20 real possibility. The downward slope of the Doppler shi= fted=20 frequency would also be indicative of an object passing by a= t constant=20 linear velocity.
 
Best 73,
Markus (DF6NM)

From: Chris
Sent: Thursday, March 03, 2011 7:55 PM
Subject: LF: Topband Test

Hi All,
Yesterday evening Pete, M0FMT, transm= itted QRSS on=20 topband for a test. An unexpected effect was noticed with the trace sp= litting in=20 two. Nothing new or 'earth shattering' I expect, but new to us and wor= thy of=20 further experimentation.
See the result and conclusion on my= website http://qsl.net/g4ayt= on the bottom of page=20 1.
I have never seen this effect on 137,= even with=20 quite strong audible signals, maybe others have.
Vy 73,
Chris, G4AYT, Whitstable,=20 UK.
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