Return-Path: Received: from mtain-df10.r1000.mx.aol.com (mtain-df10.r1000.mx.aol.com [172.29.64.222]) by air-mf08.mail.aol.com (v126.13) with ESMTP id MAILINMF081-8bf54b4a24952d7; Sun, 10 Jan 2010 14:03:49 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-df10.r1000.mx.aol.com (Internet Inbound) with ESMTP id CEF69380000E2; Sun, 10 Jan 2010 14:03:47 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NU33o-00046E-AS for rs_out_1@blacksheep.org; Sun, 10 Jan 2010 19:02:48 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NU33n-000465-Pz for rsgb_lf_group@blacksheep.org; Sun, 10 Jan 2010 19:02:47 +0000 Received: from mail-bw0-f221.google.com ([209.85.218.221]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NU33l-0003ti-7c for rsgb_lf_group@blacksheep.org; Sun, 10 Jan 2010 19:02:47 +0000 Received: by bwz21 with SMTP id 21so13483792bwz.4 for ; Sun, 10 Jan 2010 11:02:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=1hZ+NP0+NEQ1Usc6PHNHctl6gaxioBUREsH/hLSLSZY=; b=qcdSXrh4xfJqtIB1fxWmaKmaJnQOORKQD1/O2YkQLGcVd+lGI+h8MFLB2FmUDEy7YU EYq8WYEyOzcAkIMrziK7DbXRk/6+USR68pMI/nmYFQfqPvH+t5bzuWAV9DyfIffMDRND pCmKoSUoU8WP9K9mL37pV+rCiz/WqIwVtukxA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=f6EwYm12AthoDV8aOJrm0Rck9AQe6kkF6cXNcJul7jHPcD41KcN8GmddnmUrm7g9VS S/YLZI+HxdQNIkERT8MaLSC4O3TamnH5P+sPOA1teIilET5+J6pIe6eQqi5vGbOKDkkB nGXEvJHK3sH6WGnEozEybgAnEw9GHq9g/DuZc= MIME-Version: 1.0 Received: by 10.204.15.145 with SMTP id k17mr2518031bka.70.1263150158175; Sun, 10 Jan 2010 11:02:38 -0800 (PST) In-Reply-To: <000e01ca9223$6d16ec90$0517aac0@desktop> References: <000e01ca9223$6d16ec90$0517aac0@desktop> Date: Sun, 10 Jan 2010 19:02:38 +0000 Message-ID: <9afca2641001101102r6252b153lf6d911ee622589e5@mail.gmail.com> From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org X-Karma: unknown: DomainKey-Status: good (testing) X-Spam-Score: 0.3 (/) X-Spam-Report: autolearn=disabled,HTML_FONT_BIG=0.256,HTML_MESSAGE=0.001 Subject: Re: LF: Link budget calculation or estimation of dist for given power on WSPR Content-Type: multipart/alternative; boundary=000325559a6a79e071047cd4101c X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.7 required=5.0 tests=HTML_40_50, HTML_FONTCOLOR_UNKNOWN,HTML_FONT_BIG,HTML_MESSAGE 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: 3039ac1d40de4b4a24936fcb X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --000325559a6a79e071047cd4101c Content-Type: text/plain; charset=ISO-8859-1 Certainly GM4SLV has a much lower noise floor than most stations on 500kHz Jim. I think he estimated about 10dB lower, so it may be easier for him to hear very weak signals than many others. For what it's worth, my 1mW ERP has been received at -18dB S/N at 990kms range in S.Germany (and at around -23dB a few times), so assuming another 10-12dB in hand, that must be good for another skywave "hop" under favourable conditions. I am still hopeful that TF3HZ might just spot me on a good night. The magic 1000kms barrier is tantalisingly close. RN3AGC says he might just have seen a "whisper" of a trace from me the other night and he is 2400kms away, but if it was me it was far too weak to decode. It will be interesting to see what people say is possible based on the propagation theory etc. 73s Roger G3XBM 2010/1/10 James Cowburn > Dear LF, > > Has anyone any ideas or suggestions on a resource for calculation of a link > budget for WSPR over a set distance? > > As it seems I can get up to GM4SLV reasonably consistently on my current > antenna/power setting with a SNR of around -22dB and the limit for WSPR is > around -30dB then is there a means for roughly estimating or indeed > accurately calculating the Expected Max Range (EMR) at that power setting > and antenna configuration? > > Clearly, there are differences between separate Rx stations but if one > knows the ratio between two or more Rx stations then it should be possible > to pro-rate or estimate at least the signal strength at a given Rx based on > its performance with other known signals. > > If I can do 916km with an SNR of say -22dB then how much further would the > remaining 8dB or so of WSPR detection get me, assuming the other Rx has the > same capability as GM4SLV and if their capability is different, then is it > fine to factor for the dB difference over known paths/signals? > > Thanks in advance for any answers or pointers and best wishes to all for a > great 2010 > > With best regards > > > > > > *Jim* > > > > > > Dr. James Cowburn G7NKS > > E james.cowburn@virgin.net > > ** > > > -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 --000325559a6a79e071047cd4101c Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Certainly GM4SLV has a much lower noise floor than most stations on 500kHz= Jim. I think he estimated about 10dB lower, so it may be easier for him= to hear very weak signals than many others.

For what it's wort= h, my 1mW ERP has been received at -18dB S/N at 990kms range in S.Germany= (and at around -23dB a few times), so assuming another 10-12dB in hand,= that must be good for another skywave "hop" under favourable co= nditions. I am still hopeful that TF3HZ might just spot me on a good night= . The magic 1000kms barrier is tantalisingly close. RN3AGC says he might= just have seen a "whisper" of a trace from me the other night= and he is 2400kms away, but if it was me it was far too weak to decode.
It will be interesting to see what people say is possible based on the= propagation theory etc.

73s
Roger G3XBM

2010/1/10 James Cowburn <james.cowburn@virgin.net>

=A0Dear LF,

Has anyone any ideas or suggestions on a resource for calculation of a link budget for WS= PR over a set distance?

As it seems I can get up to GM4SLV reasonably consistently on my current antenna/power setti= ng with a SNR of around -22dB and the limit for WSPR is around -30dB then is= there a means for roughly estimating or indeed accurately calculating the Expect= ed Max Range (EMR) at that power setting and antenna configuration?

Clearly, there are differences between separate Rx stations but if one knows the ratio betwee= n two or more Rx stations then it should be possible to pro-rate or estimate at= least the signal strength at a given Rx based on its performance with other know= n signals.

If I can do 916km with an SNR of say -22dB then how much further would the remaining =A08dB= or so of WSPR detection get me, assuming the other Rx has the same capability= as GM4SLV and if their capability is different, then is it fine to factor for= the dB difference over known paths/signals?

Thanks in advance for any answers or pointers and best wishes to all for a great 2010=

With best re= gards

=A0

=A0

Jim

=A0

=A0

Dr. James Co= wburn G7NKS

= E james.cowburn@virgin.n= et

=A0

=A0




--

http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/G3XBM
G3XBM =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL G11088
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