Return-Path: X-Spam-DCC: paranoid 1169; 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=-2.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_50_60,HTML_MESSAGE 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 t0ABPJX6024119 for ; Sat, 10 Jan 2015 12:25:19 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Y9u4D-0006SZ-Cl for rs_out_1@blacksheep.org; Sat, 10 Jan 2015 11:18:53 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Y9u4D-0006SQ-1J for rsgb_lf_group@blacksheep.org; Sat, 10 Jan 2015 11:18:53 +0000 Received: from omr-m01.mx.aol.com ([64.12.143.75]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.84) (envelope-from ) id 1Y9u4A-0007a6-B8 for rsgb_lf_group@blacksheep.org; Sat, 10 Jan 2015 11:18:51 +0000 Received: from mtaout-mca02.mx.aol.com (mtaout-mca02.mx.aol.com [172.26.221.78]) by omr-m01.mx.aol.com (Outbound Mail Relay) with ESMTP id 6222370000083 for ; Sat, 10 Jan 2015 06:18:48 -0500 (EST) Received: from White (ipb21bee4a.dynamic.kabel-deutschland.de [178.27.238.74]) by mtaout-mca02.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id AA64E3800008E for ; Sat, 10 Jan 2015 06:18:47 -0500 (EST) Message-ID: <62E9AA6CED984ADF915F07C843D7D02F@White> From: "Markus Vester" To: References: <8D0AB94E45714E0685D511622E097CCD@malHP> <94BAB53578C64E588427A7657394BED1@AGB> <173599617.20150110004511@mterrier.net> <558FA2D95EC54559865786A671A874BC@AGB> Date: Sat, 10 Jan 2015 12:18:46 +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-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20140625; t=1420888728; bh=MLUxf4VZFHonPY6Mo89qEMGp2A2aG9OGe8xS6HwoQSI=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=Vx97I0ZL4coyyHQMmT1WiDtWhIj1I6TflkLhpg7Dz9S2xMVf+AoBxRx9CxP3d5i0H TcjpG1ASu4z8/yf8xhKuKbKMM5fPVhXz7uPrfOVTarxHKy4IzXS3pH2O1aeeLM2GVf VhJ4RfALuu462zi9ZLrntcjR/jyg5aIA6X8sTxsc= x-aol-sid: 3039ac1add4e54b10a9754af X-AOL-IP: 178.27.238.74 X-Scan-Signature: 16a6530e4735ccb856cf9bc7c6cb9773 Subject: Re: LF: MF OPERA BAD Content-Type: multipart/alternative; boundary="----=_NextPart_000_0019_01D02CCF.95130B10" 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 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 1915 Dies ist eine mehrteilige Nachricht im MIME-Format. ------=_NextPart_000_0019_01D02CCF.95130B10 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Re: LF: MF OPERA BADHi Graham, as far as I know, Stefan's RF power is actually lower than that of many = other LF stations, eg. those running ex-Decca modules. But maybe he does = have a more efficient antenna than most ;-) I have indeed been wondering about those two simultaneous WD2XNS = deep-search detections the other night. The statistical probability of = simultaneous false positives would indeed be very low if were only due = to noise. The problem is however that falses rarely pop out of the pure = noise but are often triggered by real or spurious signals, eg. other = intended transmissions or interference (like DCF39 crossmodulation). = These may be in common view of several receivers. If the waveform of any = of such signals happens to bear similarity to one of the sequences in = the search list, they are likely to pop up as false correlations.=20 Having an accurate frequency readout would help to diagnose the source = of the problem. For example, I got a number of reproducable opds falses = for R7NT, which turned out to be reproducably triggered by one PA = station who transmittied WSPR-15 sequences at these times. The pattern = on one of the WSPR frequencies code just happened to bear similarity to = R7NT's Opera sequence. This one was relatively easy to sort out from to = the out-of-band frequency and the quarter-hour timing. Here's the = excerpt from = https://dl.dropboxusercontent.com/u/26404526/opds32_archive.txt : 2014-01-26 11:00:39 R7NT 2060km 137602.968Hz 3mHz -42.2dBOp 94% = 15.2dB ? 2014-01-26 09:00:39 R7NT 2060km 137602.969Hz 2mHz -42.3dBOp 63% = 15.1dB ? ... 2014-01-25 06:15:39 R7NT 2060km 137602.969Hz 3mHz -41.9dBOp 79% = 15.4dB ? 2014-01-25 05:45:39 R7NT 2060km 137602.969Hz 4mHz -45.6dBOp 79% = 15.2dB ? ... 2014-01-24 13:30:38 R7NT 2060km 137602.968Hz 3mHz -44.3dBOp 64% = 15.7dB ? 2014-01-24 09:00:42 R7NT 2060km 137602.968Hz 2mHz -45.6dBOp 95% = 15.0dB ? ... 2013-09-11 21:30:43 R7NT 2060km 137604.888Hz 10mHz -42.2dBOp 91% = 15.0dB ? =20 Best 73, Markus (DF6NM) From: Graham=20 Sent: Saturday, January 10, 2015 1:43 AM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: MF OPERA BAD Yes the quality check is performed by the web linked server .. = as is the dynamic call list . unique decoded calls are not = added to the list . only if 2 from independent stations ...or = If using opera to Tx , then the web beacon is directly added=20 So your local decode will only show as to what your = right/wrongly detected , for dynamic false detections will all = ways be a valid call , but the system automatically validates it = , and will show in the web-linked spots =20 The probability of TWO spontaneous detections occurring at or = close to the same time are quite astronomic , possibly larger = than Stefan's RF power on 136 ?=20 73-G,=20 ... ------=_NextPart_000_0019_01D02CCF.95130B10 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Re: LF: MF OPERA BAD
Hi Graham,
 
as far as I know, Stefan's RF power is = actually=20 lower than that of many other LF stations, eg. those=20 running ex-Decca modules. But maybe he does have a more efficient = antenna=20 than most ;-)
 
I have indeed been wondering about = those two=20 simultaneous WD2XNS deep-search detections the other night. The = statistical=20 probability of simultaneous false positives would indeed be very low if = were=20 only due to noise. The problem is however that falses rarely pop = out of the=20 pure noise but are often triggered by real or spurious signals,=20 eg. other intended transmissions or interference (like DCF39=20 crossmodulation). These may be in common view of several = receivers. If=20 the waveform of any of such signals happens to bear similarity = to one=20 of the sequences in the search list, they are likely to pop up = as=20 false correlations.
 
Having an accurate frequency readout = would=20 help to diagnose the source of the problem. For example, I got a number of reproducable opds=20 falses for R7NT, which turned out to be reproducably=20 triggered by one PA station who transmittied WSPR-15 = sequences at=20 these times. The pattern on one of the WSPR frequencies code just = happened=20 to bear similarity to R7NT's Opera sequence. This one was = relatively easy=20 to sort out from to the out-of-band frequency and the quarter-hour = timing.=20 Here's the excerpt from = https://dl.dropboxusercontent.com/u/26404526/opds32_archive.txt = :
 
2014-01-26 11:00:39 = R7NT    2060km=20 137602.968Hz   3mHz -42.2dBOp  94% 15.2dB ?
2014-01-26 09:00:39 = R7NT    2060km=20 137602.969Hz   2mHz -42.3dBOp  63% 15.1dB = ?
...
2014-01-25 06:15:39 = R7NT    2060km=20 137602.969Hz   3mHz -41.9dBOp  79% 15.4dB ?
2014-01-25 = 05:45:39 R7NT    2060km 137602.969Hz   4mHz=20 -45.6dBOp  79% 15.2dB ?
...
2014-01-24 13:30:38 = R7NT    2060km=20 137602.968Hz   3mHz -44.3dBOp  64% 15.7dB ?
2014-01-24 = 09:00:42 R7NT    2060km 137602.968Hz   2mHz=20 -45.6dBOp  95% 15.0dB ?
...
2013-09-11 21:30:43 = R7NT    2060km=20 137604.888Hz  10mHz -42.2dBOp  91% 15.0dB ?
 
Best 73,
Markus = (DF6NM)

From: Graham
Sent: Saturday, January 10, 2015 1:43 AM
To: rsgb_lf_group@blacksheep.org= =20
Subject: Re: LF: MF OPERA BAD

Yes  the  quality  check  is  = performed =20 by  the  web linked  server  .. as  is  = the =20 dynamic  call  list .   unique  decoded=20  calls  are  not  added  to  the  = list=20 .  only  if  2  from  independent  = stations=20 ...or   If using  opera  to  Tx , then  = the =20 web  beacon  is directly  added
 
So your  local  decode  will  only  = show =20 as  to  what  your   right/wrongly  = detected =20 , for  dynamic  false  detections  will  all = ways =20 be a  valid  call  , but the  system =20 automatically  validates  it  ,  and  = will =20 show  in the  web-linked  spots  
 
The  probability  of  = TWO   spontaneous =20  detections  occurring  at  or  close  = to =20 the  same  time  are  quite  astronomic  , = possibly  larger than  Stefan's   RF power on 136 =   ?=20
 
73-G,
 ...
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