Return-Path: Received: from mtain-md02.r1000.mx.aol.com (mtain-md02.r1000.mx.aol.com [172.29.96.86]) by air-df01.mail.aol.com (v126.13) with ESMTP id MAILINDF013-5ee44b4a2aca196; Sun, 10 Jan 2010 14:30:18 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-md02.r1000.mx.aol.com (Internet Inbound) with ESMTP id ABEE1380007B1; Sun, 10 Jan 2010 14:30:16 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NU3TS-0004JT-Bn for rs_out_1@blacksheep.org; Sun, 10 Jan 2010 19:29:18 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NU3TR-0004JK-PY for rsgb_lf_group@blacksheep.org; Sun, 10 Jan 2010 19:29:17 +0000 Received: from out1.ip09ir2.opaltelecom.net ([62.24.128.245]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NU3TO-00044w-Uz for rsgb_lf_group@blacksheep.org; Sun, 10 Jan 2010 19:29:17 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ArEFAJa4SUtcG7vU/2dsb2JhbACCFYs/BsQlhC8E X-IronPort-AV: E=Sophos;i="4.49,251,1262563200"; d="scan'208,217";a="417664169" Received: from unknown (HELO xphd97xgq27nyf) ([92.27.187.212]) by out1.ip09ir2.opaltelecom.net with SMTP; 10 Jan 2010 19:28:47 +0000 Message-ID: <004101ca922b$214cf0e0$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <000e01ca9223$6d16ec90$0517aac0@desktop> <9afca2641001101102r6252b153lf6d911ee622589e5@mail.gmail.com> Date: Sun, 10 Jan 2010 19:28:46 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Karma: unknown: 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="----=_NextPart_000_003E_01CA922B.20F4BEC0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.0 required=5.0 tests=HTML_30_40, 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: 3039ac1d60564b4a2ac80dae X-AOL-IP: 193.82.116.20 ------=_NextPart_000_003E_01CA922B.20F4BEC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Had u been on QRS CW he probably would have copied u since he saw ur= trace. I often see traces that do not decode for some time but had th= e trace been keyed it could have been identified. I have been making this point for some time, avoid guesswork and specu= lation and use normal CW or QRS CW Regardless of erp transmitted the weakness is often at the RX end Litt= le antenna Little signal Big antenna Big signal and environment regard= ing noise. RX loop antennas not optimised towards ur stn, these situations cannot= be calculated just guessed and meaningless. Get into QSO mode and see how far u can get in real time. G3KEV ----- Original Message -----=20 From: Roger Lapthorn=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Sunday, January 10, 2010 7:02 PM Subject: Re: LF: Link budget calculation or estimation of dist for= given power on WSPR 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 easie= r 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 99= 0kms 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 fro= m 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 limi= t for WSPR is around -30dB then is there a means for roughly estimatin= g or indeed accurately calculating the Expected Max Range (EMR) at tha= t 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 gi= ven 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 --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 ------=_NextPart_000_003E_01CA922B.20F4BEC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Had u been on QRS CW he probably woul= d have copied=20 u since he saw ur trace. I often see traces that do not decode for som= e time but=20 had the trace been keyed it could have been identified.
I have been making this point for som= e time, avoid=20 guesswork and speculation and use normal CW or QRS CW
Regardless of erp transmitted the wea= kness is often=20 at the RX end Little antenna Little signal Big antenna Big signal and= =20 environment regarding noise.
RX loop antennas not optimised toward= s ur stn,=20 these situations cannot be calculated just guessed and meaningless.
Get into QSO mode and see how far u= can get in real=20 time.
 
G3KEV
 
----- Original Message -----
Sent: Sunday, January 10, 201= 0 7:02=20 PM
Subject: Re: LF: Link budget= calculation=20 or estimation of dist for given power on WSPR

Certainly GM4SLV has a much lower noise floor than mo= st=20 stations on 500kHz Jim. I think he estimated about 10dB lower, so it= may be=20 easier for him to hear very weak signals than many others.

Fo= r what=20 it's worth, my 1mW ERP has been received at -18dB S/N at 990kms rang= e in=20 S.Germany (and at around -23dB a few times), so assuming another 10-= 12dB in=20 hand, that must be good for another skywave "hop" under favourable= conditions.=20 I am still hopeful that TF3HZ might just spot me on a good night. Th= e magic=20 1000kms barrier is tantalisingly close. RN3AGC says he might just ha= ve seen a=20 "whisper" of a trace from me the other night and he is 2400kms away,= but if it=20 was me it was far too weak to decode.

It will be interesting= to see=20 what people say is possible based on the propagation theory=20 etc.

73s
Roger G3XBM

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

 Dear LF,

Has anyone any ideas or suggestions= on a resource=20 for calculation of a link budget for WSPR over a set=20 distance?

As it seems I can get up to GM4SLV re= asonably=20 consistently on my current antenna/power setting with a SNR of aro= und -22dB=20 and the limit for WSPR is around -30dB then is there a means for= roughly=20 estimating or indeed accurately calculating the Expected Max Range= (EMR) at=20 that power setting and antenna configuration?

Clearly, there are differences betwee= n separate Rx=20 stations but if one knows the ratio between two or more Rx station= s then it=20 should be possible to pro-rate or estimate at least the signal str= ength at a=20 given Rx based on its performance with other known=20 signals.

If I can do 916km with an SNR of say= -22dB then how=20 much further would the remaining  8dB or so of WSPR detection= get me,=20 assuming the other Rx has the same capability as GM4SLV and if the= ir=20 capability is different, then is it fine to factor for the dB diff= erence=20 over known paths/signals?

Thanks in advance for any answers or= pointers and=20 best wishes to all for a great 2010

Wit= h best=20 regards

 

 

Jim

 

 

Dr.= James Cowburn=20 G7NKS

E=20 james.cowburn@virgin.net<= FONT face=3DArial color=3Dblue>

 

 

<= /BLOCKQUOTE>



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