Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dd06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 3B4D338000151; Sun, 23 Jun 2013 08:37:33 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1UqjWK-000519-Eo for rs_out_1@blacksheep.org; Sun, 23 Jun 2013 13:35:52 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1UqjWJ-000510-O5 for rsgb_lf_group@blacksheep.org; Sun, 23 Jun 2013 13:35:51 +0100 Received: from smtpout3.wanadoo.co.uk ([80.12.242.59] helo=smtpout.wanadoo.co.uk) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1UqjWH-0005wp-0e for rsgb_lf_group@blacksheep.org; Sun, 23 Jun 2013 13:35:50 +0100 Received: from AGB ([95.145.213.1]) by mwinf5d34 with ME id robm1l00A02NUDK03obmPD; Sun, 23 Jun 2013 14:35:47 +0200 Message-ID: From: "Graham" To: References: <67BD952BF77F49FD826969BF2E7CC824@White> In-Reply-To: Date: Sun, 23 Jun 2013 13:35:46 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 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: Interesting points Marcus , Assuming the Tx station declared the make up of the call , the system could be made to work ? As for the differing decode dB levels , there is 'no' actual cliff , the minimum Op decode level is set with regard to a number of factors , ie false decodes , lowering the bar may result in more 'real' decodes , but with a increase in false ones , at the moment , it seems to be 'about right' ? [...] 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 [80.12.242.59 listed in list.dnswl.org] 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: dd7342f7a67c58184f15e70b9d6d7f8e Subject: Re: LF: VO1NA Opera-32 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0071_01CE7016.90F65FE0" 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: 3039ac1d409251c6ec0b3519 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : temperror This is a multi-part message in MIME format. ------=_NextPart_000_0071_01CE7016.90F65FE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Interesting points Marcus ,=20 Assuming the Tx station declared the make up of the call , the = system could be made to work ? As for the differing decode dB levels , there is 'no' actual = cliff , the minimum Op decode level is set with regard to a = number of factors , ie false decodes , lowering the bar may = result in more 'real' decodes , but with a increase in false ones = , at the moment , it seems to be 'about right' ? =20 Noting , that Opera was designed to accommodate a hardware = limitation, ie to replace a cw key , where as the wspr system = conversely , dictates hardware requirements , ie stability , remote = sync time , vfo control .=20 The differing modulation systems , do have numeric differences , = wspr with 4 fsk , will have a inherent gain over 1 tone OOK , = OOK also loosing 50% of the 'energy' -3dB , on paper this dose = give an advantage to 4fsk , but over a real path , the Op system = , with dedicated data processing and fec , linked with the DSP = engines design , that can maximise 'flutter' and reject noise , on = air, results with similar carrier levels are very similar and = in high noise , the non linear routines in the dsp are able to = maintain performance under quite 'extreme' conditions . OP is a = averaging system and differs significantly from conventional data = methods=20 The only , point that should be stressed , is , that the Op = software is decoding data , with no pre information , the call = sign or in the case of the QSO mode , 15 chrs plain text , the = correlation system is detecting with a system pre-load , making the = decision as to the authenticity of the detection=20 But in saying that , in keeping with LF , an authenticated detection = is an improvement ! 73 -G.. =20 From: Markus Vester=20 Sent: Saturday, June 22, 2013 9:24 PM To: rsgb_lf_group@blacksheep.org ; rsgb_lf_group@yahoogroups.co.uk=20 Subject: Re: LF: VO1NA Opera-32 Hi Graham,=20 good question... Edgar J Twining from Tasmania asked the same a while = ago. You'll find the respective emails posted beneath.=20 Best 73, Markus (DF6NM) From: Graham=20 Sent: Saturday, June 22, 2013 9:48 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: VO1NA Opera-32 Marcus=20 Q what advantage could you have , using this to detect wspr-15 ? = that has a fixed pattern and a known start time ?=20 G.. From: Markus Vester=20 Sent: Thursday, February 21, 2013 1:10 AM To: edgar=20 Subject: Re: "Deep search analysis" Edgar, yes, at least in principle. I had actually looked into WSPR and QRSS = correlation before turning to Opera. With Opera, it looks like I can = detect up to 10 to 12 dB deeper than the standard decoder. But I think = there is simply less to gain with WSPR. The first step in my procedure is searching for a carrier. If Opera is = transmitted phase-coherently, it's just classic AM, with 50 % of the = transmitted energy contained in a central spectral line. This is = relatively easy to detect eg. with a long 0.47 mHz FFT. On the other = hand, WSPR shares it's "carrier" power among four equispaced lines, = which lets them stand out less above the noise.=20 My second step then uses the detected carrier as a pilot to correct for = small amounts of drift and propagational phase variations. This could = probably be done equally well with a coherent sum of four carriers as = long as their spacing is accurate. The third step, the actual = correlation against a number of precalculated list of templates, should = also be comparable for the two modes. The main difference is however that Joe's WSPR decoder seems to be much = more efficient in the first place than Jose's bit-power based Opera = decoder. For same message time, the difference is said to be about 6 to = 7 dB. So there is simply less to gain by using all the available signal = energy in a correlation process. Another difficulty is that WSPR actually transmits more information than = just the callsign. So for preparing the templates, you would have to = include locator and power as a priori information. I have also looked at integrating subsequent repeats of WSPR. It is = fairly straightforward to stack them incoherently, in essence like = averaging the brightness of successive spectrograms. However this gains = only 1.5 dB per doubling of aquisition time. Coherent superposition is = more attractive (3 dB for double time), but requires extremely stable = signals over long periods of time, and a milliHz search for the exact = phase shift from one repeat to the next. Best 73, Markus (DF6NM) ----- Original Message -----=20 From: edgar=20 To: Markus Vester=20 Cc: Stefan Sch=E4fer=20 Sent: Wednesday, February 20, 2013 12:49 AM Subject: "Deep search analysis" Hi Markus, Can you "deep search analysis" that you applied to OPERA signals be = usefully applied to WSPR signals? Regards, Edgar. ------=_NextPart_000_0071_01CE7016.90F65FE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Interesting points Marcus ,
 
Assuming the  Tx station  declared  the  make = up of=20 the  call  , the  system could be  made to   = work=20 ?
 
As for the  differing  decode  dB levels  = , =20 there  is 'no'   actual  cliff , the =20 minimum   Op decode  level  is set  with =20 regard  to a  number  of  factors ,  ie =20 false  decodes  , lowering the  bar  may  = result in=20 more  'real' decodes  , but  with  a  = increase  in=20 false ones , at the  moment , it seems  to  be  = 'about=20 right'  ? 
 
Noting  , that  Opera  was  designed to =20 accommodate  a  hardware  limitation, ie  to  = replace a=20 cw  key  , where  as the  wspr  system  = conversely=20 , dictates  hardware requirements , ie stability , remote sync time = ,=20 vfo  control .
 
The  differing  modulation  systems  , do = have =20 numeric differences ,  wspr  with  4 fsk  , = will  have=20 a  inherent  gain over  1 tone  OOK ,  OOK=20 also  loosing   50% of the  'energy'  = -3dB  , on=20 paper  this  dose give an advantage to  4fsk  = , =20 but  over a  real  path , the  Op system , = with =20 dedicated   data  processing  and  fec  ,=20 linked  with the  DSP  engines  design , that =20 can  maximise 'flutter' and reject  noise  , on air, =  =20 results  with similar  carrier  levels  are  = very =20 similar  and  in high  noise , the  non linear=20 routines  in the  dsp  are  able to  = maintain=20 performance  under quite  'extreme' conditions .  OP is = a =20 averaging  system and  differs  significantly  = from =20 conventional data  methods
 
The  only  , point that  should  be =20 stressed  , is , that  the  Op software  is =20 decoding  data , with  no  pre information  =  ,=20 the  call  sign or in the  case of the  QSO  = mode ,=20 15  chrs  plain text  , the  correlation  = system=20 is  detecting  with  a system pre-load , making the  = decision as to  the  authenticity of the  detection =
 
But in saying that , in keeping  with  LF  , an=20 authenticated  detection  is  an improvement !
 
73 -G..
 
 
 

 
From: Markus Vester
Sent: Saturday, June 22, 2013 9:24 PM
To: rsgb_lf_group@blacksheep.org= ; rsgb_lf_group@yahoogroups= .co.uk=20
Subject: Re: LF: VO1NA Opera-32

Hi Graham,
 
good question... Edgar J Twining = from Tasmania=20 asked the same a while ago. You'll find the respective emails = posted=20 beneath. 
 
Best 73,
Markus (DF6NM)

From:=20 Graham
Sent: Saturday, June 22, = 2013 9:48=20 PM
To: rsgb_lf_group@blacksheep.org=20
Subject: Re: LF: VO1NA=20 Opera-32

Marcus
 
Q   what  advantage = could you =20 have , using  this to  detect  wspr-15  ? that  = has=20 a  fixed  pattern  and a  known start time ? =
 
G..

Sent: Thursday, = February 21,=20 2013 1:10 AM
To: edgar =
Subject: Re: "Deep search = analysis"

Edgar,
 
yes, at=20 least in principle. I had actually looked into WSPR and QRSS correlation = before=20 turning to Opera. With Opera, it looks like I can detect up to 10 = to 12 dB=20 deeper than the standard decoder. But I think there is simply less = to gain=20 with WSPR.
 
The first=20 step in my procedure is searching for a carrier. If Opera is = transmitted=20 phase-coherently, it's just classic AM, with 50 % of=20 the transmitted energy contained in a central spectral line.=20 This is relatively easy to detect eg. with a long 0.47 mHz = FFT. On the=20 other hand, WSPR shares it's "carrier" = power among four=20 equispaced lines, which lets them stand out less above the noise.=20
 
My second=20 step then uses the detected carrier as a pilot to correct for small = amounts of=20 drift and propagational phase variations. This could probably be done=20 equally well with a coherent sum of four carriers as long as their = spacing=20 is accurate. The third step, the actual correlation against a number of=20 precalculated list of templates, should also be comparable for the two=20 modes.
 
The main=20 difference is however that Joe's WSPR decoder seems to be much = more=20 efficient in the first place than Jose's bit-power based Opera decoder. = For same=20 message time, the difference is said to be about 6 to 7 dB. So there is = simply=20 less to gain by using all the available signal energy in a = correlation=20 process.
 
Another=20 difficulty is that WSPR actually transmits more information than just = the=20 callsign. So for preparing the templates, you would have to include = locator=20 and power as a priori information.
 
I have also=20 looked at integrating subsequent repeats of WSPR. It is fairly=20 straightforward to stack them incoherently, in essence like averaging = the=20 brightness of successive spectrograms. However this gains only 1.5 = dB per=20 doubling of aquisition time. Coherent superposition is more = attractive (3=20 dB for double time), but requires extremely stable signals over = long=20 periods of time, and a milliHz search for the exact phase shift from one = repeat=20 to the next.
 
Best=20 73,
Markus=20 (DF6NM)
 
----- Original = Message -----=20
From: edgar=20
To: Markus=20 Vester
Cc: Stefan=20 Sch=E4fer
Sent: = Wednesday,=20 February 20, 2013 12:49 AM
Subject: = "Deep search=20 analysis"

Hi=20 Markus,
 
    Can you "deep search analysis" that you = applied to=20 OPERA signals be usefully applied to WSPR signals?

Regards,=20 Edgar.

 
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