Return-Path: Received: from mtain-md12.r1000.mx.aol.com (mtain-md12.r1000.mx.aol.com [172.29.96.96]) by air-mf10.mail.aol.com (v129.4) with ESMTP id MAILINMF102-8bfe4c2ddce26f; Fri, 02 Jul 2010 08:34:42 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-md12.r1000.mx.aol.com (Internet Inbound) with ESMTP id 7515738000137; Fri, 2 Jul 2010 08:34:39 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OUfR3-00042D-Df for rs_out_1@blacksheep.org; Fri, 02 Jul 2010 13:33:37 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OUfR2-00040v-Eg for rsgb_lf_group@blacksheep.org; Fri, 02 Jul 2010 13:33:36 +0100 Received: from [80.12.242.2] (helo=smtp6.freeserve.com) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OUfR1-0006Bl-7U for rsgb_lf_group@blacksheep.org; Fri, 02 Jul 2010 13:33:36 +0100 Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3j18.me.freeserve.com (SMTP Server) with ESMTP id 841B73000146 for ; Fri, 2 Jul 2010 14:33:29 +0200 (CEST) Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3j18.me.freeserve.com (SMTP Server) with ESMTP id 783373000148 for ; Fri, 2 Jul 2010 14:33:29 +0200 (CEST) Received: from AGB (unknown [91.110.88.95]) by mwinf3j18.me.freeserve.com (SMTP Server) with SMTP id 230B43000146 for ; Fri, 2 Jul 2010 14:33:29 +0200 (CEST) X-ME-UUID: 20100702123329143.230B43000146@mwinf3j18.me.freeserve.com Message-ID: <441C40E5D38B4E0FBAF138D14BCE5C5D@AGB> From: "Graham" To: References: <063F5E5A75EC43DEB446F850ED876141@AGB> In-Reply-To: Date: Fri, 2 Jul 2010 13:33:28 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8089.726 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8089.726 X-Antivirus: avast! (VPS 100702-0, 02/07/2010), Outbound message X-Antivirus-Status: Clean X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: 137.500 kHz ROS MF-1 beacon Content-Type: multipart/alternative; boundary="----=_NextPart_000_00B1_01CB19EB.27EE51D0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.6 required=5.0 tests=HTML_40_50,HTML_FONTCOLOR_RED, HTML_MESSAGE,MISSING_OUTLOOK_NAME,WEIRD_PORT 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: 3039ac1d60604c2ddcdf3900 X-AOL-IP: 193.82.116.20 ------=_NextPart_000_00B1_01CB19EB.27EE51D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Reply from R . MF1 ROS is 0.837053 symbols/second. If you can decode at -33dB (presu= mably in the reference bandwidth of 2.5kHz) that's +1.7 dB S/N in a= symbol bandwidth, that in the case of 16FSK with Viterbi Decoder is= possible. ROS calculate S/N for 100Hz, after tx , show's S/N for an equivalent= system of 2500Hz >> CANCEL> -36 dB << (end of rx text string) From: Andy Talbot=20 Sent: Friday, July 02, 2010 8:01 AM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: 137.500 kHz ROS MF-1 beacon A thought. =20 MF1 ROS is one symbol per second isn't it. If you can decode at -33dB= (presumably in the reference bandwidth of 2.5kHz) that's -1dB S/N in= a symbol bandwidth. Which I'm not sure I can believe. FSK with go= od Feed Solomon, or whatever, FEC needs 2 - 3dB S/N.=20 Is the S/N calculation being a bit optimistic? The calculation in WSJ= T / WSPR gives an artificially high S/N value if the input bandwidth= is restricted below a complete 2.5kHz's worth, and if impulsive noise= is present. So could ROS be suffering some similar effect? Andy www.g4jnt.com On 1 July 2010 23:47, Graham wrote: Gary,=20 Just a couple of db's short of a decode via the web , -36 is= going some though=20 http://websdr.ewi.utwente.nl:8901/ RX1:=20 21:55 @ 13.8 Hz: *[:]V-KFY:32DM5#("")EM3H#/F[_ -36 dB=20 G ..=20 From: Gary - G4WGT=20 Sent: Thursday, July 01, 2010 6:35 PM To: LF Group (RSGB)=20 Subject: LF: 137.500 kHz ROS MF-1 beacon Hi LF,=20 My ROS MF-1 beacon is transmitting now with 3 minute timer. Frequency is 137.500 kHz (dial 136.500 kHz USB), reports & QSO attem= pts very welcome. ERP about 50mW. 73 Gary - G4WGT - IO83QO ------=_NextPart_000_00B1_01CB19EB.27EE51D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Reply  from R .
 
MF1 ROS is=20 0.837053 symbols/second.  If you can decode at= -33dB=20 (presumably in the reference bandwidth of 2.5kHz)  that's +1.7 dB= =20 S/N in a symbol bandwidth, that in the case of 16FSK with=20 Viterbi Decoder is possible.
ROS calculate=20 S/N for 100Hz, after tx ,  show's  S/N for an equivalent sys= tem of=20 2500Hz   >>  CANCEL&g= t; -36 dB=20 <<  (end of rx text string)
 

Sent: Friday, July 02, 2010 8:01 AM
Subject: Re: LF: 137.500 kHz ROS MF-1 beacon

A thought. 
MF1 ROS is one symbol per second isn't it.  If you can decod= e at -33dB=20 (presumably in the reference bandwidth of 2.5kHz)  that's -1dB S/= N in a=20 symbol bandwidth.   Which I'm not sure I can believe. &= nbsp; FSK=20 with good Feed Solomon, or whatever, FEC  needs 2 - 3dB S/N.
 
Is the S/N calculation being a bit optimistic?  The calculat= ion in=20 WSJT / WSPR gives an artificially high S/N value if the input bandwidt= h is=20 restricted below a complete 2.5kHz's worth, and if impulsive noise is= =20 present.  So could ROS be suffering some similar effect?
On 1 July 2010 23:47, Graham = <g8fzk@g8fzk.fs= net.co.uk>=20 wrote:
 
Gary,
 
Just a  couple of db's &n= bsp;=20 short  of a  decode  via the  web , -36 is going= some=20 though
 

RX1:

21:55 @ 13.8 Hz: *[:= ]V-KFY:32DM5#("")EM3H#/F[_ <CANCEL>= =20 -36 dB=20

G ..

 

Sent: Thursday, July 01, 2010 6:35 PM
Subject: LF: 137.500 kHz ROS MF-1 beacon

Hi LF,=20

My ROS MF-1 beacon is transmitting now with 3 minute timer.

Frequency is 137.500 kHz (dial 136.500 kHz USB), reports &= QSO=20 attempts very welcome.

ERP about 50mW.

73

Gary - G4WGT -=20 IO83QO





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