Return-Path: Received: from mtain-dh10.r1000.mx.aol.com (mtain-dh10.r1000.mx.aol.com [172.29.65.30]) by air-mf01.mail.aol.com (v126.13) with ESMTP id MAILINMF013-8bcb4b4b999f3db; Mon, 11 Jan 2010 16:35:27 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dh10.r1000.mx.aol.com (Internet Inbound) with ESMTP id 8426B38000102; Mon, 11 Jan 2010 16:35:24 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NURtv-0005mF-K0 for rs_out_1@blacksheep.org; Mon, 11 Jan 2010 21:34:15 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NURtu-0005m6-7q for rsgb_lf_group@blacksheep.org; Mon, 11 Jan 2010 21:34:14 +0000 Received: from mtaout01-winn.ispmail.ntl.com ([81.103.221.47]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NURto-0001F7-Uu for rsgb_lf_group@blacksheep.org; Mon, 11 Jan 2010 21:34:14 +0000 Received: from know-smtpout-1.server.virginmedia.net ([62.254.123.1]) by mtaout01-winn.ispmail.ntl.com (InterMail vM.7.08.04.00 201-2186-134-20080326) with ESMTP id <20100111212903.EQSX4204.mtaout01-winn.ispmail.ntl.com@know-smtpout-1.server.virginmedia.net> for ; Mon, 11 Jan 2010 21:29:03 +0000 Received: from [86.26.81.210] (helo=desktop) by know-smtpout-1.server.virginmedia.net with esmtp (Exim 4.63) (envelope-from ) id 1NURos-00049W-1S for rsgb_lf_group@blacksheep.org; Mon, 11 Jan 2010 21:29:03 +0000 From: "James Cowburn" To: References: <000001ca9252$1b65f240$0202a8c0@laptopcore2> Date: Mon, 11 Jan 2010 21:28:56 -0000 Message-ID: <019801ca9305$14cd9f60$0517aac0@desktop> MIME-Version: 1.0 X-Mailer: Microsoft Office Outlook 11 In-Reply-To: <000001ca9252$1b65f240$0202a8c0@laptopcore2> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3350 Thread-Index: AcqSUkoAfg29Muo7S7mNP9fisdQvawAscYNw X-Cloudmark-Analysis: v=1.1 cv=W3tOLUehizD4qj6VhtReFuw5MKb8d+XqjIxlDsIazEA= c=1 sm=0 a=8Qw2kvqKHfsA:10 a=8RloEfZUAAAA:8 a=F3M5lZpKAAAA:8 a=wV9FcBFsAAAA:8 a=pGLkceISAAAA:8 a=nN7BH9HXAAAA:8 a=fnYqA7hvAAAA:8 a=j6Q1dnSHAAAA:8 a=A06HpNCPAAAA:20 a=oCcaPWc0AAAA:8 a=xMqyt3UgjxdnjCguF4YA:9 a=BDRFzisxNfwToGLRM68A:7 a=XI7nYwZrqk4w780n380rqZBhSTgA:4 a=ftx3PimO_ywA:10 a=KGHlO6L4b5AA:10 a=O58u2wXj750A:10 a=wk6s2zzMB60A:10 a=MSl-tDqOz04A:10 a=muIvw5a9-cgA:10 a=gA6IeH5FQcgA:10 a=NWVoK91CQyQA:10 a=ESaNNTV9vPqTbjqu:21 a=mpCNt4wGCMLj1mgP:21 a=SSmOFEACAAAA:8 a=rnjTaxgTU2JznvQ55TIA:9 a=XGxwT880DwO3lXbCYX0A:7 a=cS22jEknwkEmvhCY_3xqH3IJTlYA:4 a=tVPGMQhxPUiaUzPx:21 a=sWPS5rQx1gq_h8zk:21 a=HpAAvcLHHh0Zw7uRqdWCyQ==:117 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_0199_01CA9305.14CD9F60" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.4 required=5.0 tests=HTML_50_60, 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: 3039ac1d411e4b4b999c547b X-AOL-IP: 193.82.116.20 ------=_NextPart_000_0199_01CA9305.14CD9F60 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit We are obviously mainly engineers here!. A question was asked, and has been responded too in some considerable depth and detail and diverging opinions proffered. The questioner now knows a little more than he did at the start, but without an explicit answer to the question asked, other than "it depends"! Of course if we were consultants we would tell people what they already knew after asking them first and then charge them for it! Thanks for all the replies, and It looks like I am going to need "considerably bigger buns"! With best regards Jim Dr. James Cowburn E james.cowburn@virgin.net From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of g3zjo Sent: 11 January 2010 00:08 To: rsgb_lf_group@blacksheep.org Subject: RE: LF: Link budget calculation or estimation of dist for given power on WSPR Thanks Andy and all interested in the group for the information. Surely there is nothing like a practical experiment for proof of WSPR effectiveness against QRSS3 on 500KHz. I have been running that experiment since the 17th of November 2009. Results so far have been, hundreds of WSPR reports from 7different stations and not one mention of the QRSS3 content. My MEPT runs a 100% Transmit cycle, hence once I got a reliably detectable signal out I posted this to the UK500KHz Group on the 28th of November 2009. :- "Between the WSPR is QRSS Morse and some small font Hell which looks best on Spectran QRSS3 Mode. This means it's a continuous TX sequence. I think at the bottom of the WSPR Window and with such low power it should not cause any problems to any other stations. Please let me know if there are any concerns." I have run MEPT's on continuous transmit tests at the bottom the WSPR slot on other low occupancy bands without any problems too. I always use QRPp. After all who is going to complain about the QRSS3 etc. content of the signal that has never been seen? As I have mentioned before, there has to be a challenge in there somewhere for the guys with big antennas. There is a simple 2 letter ident in there in 2 QRSS3 modes as well as more complex stuff and full Call Sign.. Eddie G3ZJO IO92ng -----Original Message----- From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Andy Talbot Sent: 10 January 2010 21:20 To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Link budget calculation or estimation of dist for given power on WSPR Making comparisons between WSPR and QRSS should take into account the signalling rate, and it is only fair to compare like with like. A WSPR transmission carries a callsign, a locator and a power level. Approximately 12 characters worth of data, or in Morse code terms around 2.4 words which it sends in 2 minutes - hence about 1.2 WPM. If 12WPM beans 100ms dots, then this rate corresponds to a dot interval of 1 second. So for a fair comparison, you must compare WSPR with 1s QRS - which I believe is faster than most ops actually use. The version of Argo I have only goes down to 3s dots which infers 5dB bandwidth improvement immediately. So if, as I recall someone saying here, WSPR and 3s QRSS give similar decoding capability, then that immediately suggests WSPR is 5dB 'up' on QRSS, or QRSS takes three times longer for the same message. Its rather more complicated in reality, as this simple ccomparison assumes the QRS signal is copied with zero errors. As it involves fuzzy logic and human interpretation, we can probably say it contributes the error correction To compare data modes in noise, its best to use a normalised data rate expressed in Bits/second/Hz See http://www.g4jnt.com/MartleSham.htm where I come up with an empirically determined estimate that the WSJT modes, WSPR, JT4, etc give about 6dB enhancement in S/N vs. decoding than CW - when normalised for an equivalent signalling rate. Andy www.g4jnt.com This email has been scanned for damaging side-effects by the health and safety police, is guaranteed to contain no substances hazardous to health, but may contribute to dissolving the nether and polar regions 2010/1/10 Roger Lapthorn Fair comment Mal, and one of these days I'll try QRS and see how it performs. It should be possible to get a pretty good idea of the theoretical range limit for WSPR on 500kHz based on required S/N (which can be as low as -30dB for WSPR), path loss calculations, ERP etc.. I shall be interested to see what "the experts" say. 73s Roger G3XBM 2010/1/10 mal hamilton 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 the trace been keyed it could have been identified. I have been making this point for some time, avoid guesswork and speculation and use normal CW or QRS CW Regardless of erp transmitted the weakness is often at the RX end Little antenna Little signal Big antenna Big signal and environment regarding 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 ----- From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org 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 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 -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.725 / Virus Database: 270.14.133/2612 - Release Date: 01/10/10 19:35:00 ------=_NextPart_000_0199_01CA9305.14CD9F60 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

We are obviousl= y mainly engineers here!.   A question was asked, and has been responded too in some considerable de= pth and detail and diverging opinions proffered.  The questioner now know= s a little more than he did at the start, but without an explicit answer= to the question asked, other than “it depends”!=

 

Of course if we= were consultants we would tell people what they already knew after asking them first and then ch= arge them for it!

 

Thanks for all= the replies, and It looks like I am going to need “considerably bigger buns”!

 

With best regards=

 

Jim

 

 

Dr. James Cowbu= rn

&= nbsp;

E james.cowburn@virgin.net

 

From: owner-rsgb_lf_group@blac= ksheep.org [mailto:owner-= rsgb_lf_group@blacksheep.org] On Behalf Of g3zjo
Sent: 11 January 2010= 00:08
To: rsgb_lf_group@blacksheep.org
Subject: RE: LF: Link= budget calculation or estimation of dist for given power on WSPR

 

Tha= nks Andy and all interested in the group for the information.

&nb= sp;

Sur= ely there is nothing like a practical experiment for proof of WSPR effectiveness against QR= SS3 on 500KHz. I have been running that experiment since the 17th= of November 2009.

&nb= sp;

Res= ults so far have been, hundreds of WSPR reports from 7different stations and not one mention= of the QRSS3 content.

&nb= sp;

My= MEPT runs a 100% Transmit cycle, hence once I got a reliably detectable signal out I po= sted this to the UK500KHz Group on the 28th of November 2009. :-

&nb= sp;

“Between the WSPR is QRSS= Morse and some small font Hell which looks best
on Spectran QRSS3 Mode. This means it's a continuous TX sequence. I think at the bottom of the WSPR Window and with such low power it shou= ld
not cause any problems to any other stations. Please let me know if there are any concerns.”

 

I have ru= n MEPT’s on continuous transmit tests at the bottom the WSPR slot on other low occ= upancy bands without any problems too. I always use QRPp. After all who is go= ing to complain about the QRSS3 etc. content of the signal that has never bee= n seen?

 

As I have= mentioned before, there has to be a challenge in there somewhere for the guys with big= antennas. There is a simple 2 letter ident in there in 2 QRSS3 modes as well as= more complex stuff and full Call Sign..

&nb= sp;

&nb= sp;

Eddie G3ZJO IO92ng

&nb= sp;

-----Ori= ginal Message-----
From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org= ] On Behalf Of Andy Talbo= t
Sent: 10 January 2010= 21:20
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Link= budget calculation or estimation of dist for given power on WSPR

&nb= sp;

Mak= ing comparisons between WSPR and QRSS should take into account the signall= ing rate, and it is only fair to compare like with like.

&nb= sp;

A= WSPR transmission carries a callsign, a locator and a power level.  Approximately 12 characters worth of data, or in Morse code terms around 2.4 words which it sends in 2 minutes - he= nce about 1.2 WPM.  If 12WPM beans 100ms dots, then this rate correspo= nds to a dot interval of 1 second.  So for a fair comparison, you = must compare WSPR with 1s QRS - which I believe is faster than most ops act= ually use.   The version of Argo I have only goes down to 3s dots= which infers 5dB bandwidth improvement immediately.=

&nb= sp;

So= if, as I recall someone saying here, WSPR and 3s QRSS give similar decoding cap= ability, then that immediately suggests WSPR is 5dB 'up' on QRSS, or QRSS= takes three times longer for the same message.  

&nb= sp;

Its= rather more complicated in reality,  as this simple ccomparison assumes= the QRS signal is copied with zero errors.  As it involves fuzzy logic an= d human interpretation, we can probably say it contributes the error corr= ection

&nb= sp;

To= compare data modes in noise, its best to use a normalised data rate expre= ssed in Bits/second/Hz 

See= http://www.g4jnt.com/= MartleSham.htm where I come up with an empirically determined estimate that the WSJT modes,= WSPR, JT4, etc give about 6dB enhancement in S/N vs. decoding than CW - when normalised for an equivalent signalling rate.=

&nb= sp;


Andy
www.g4jnt.com

This email has been scanned for damaging side-effects by the health an= d safety police, is guaranteed to contain no substances hazardous to health, bu= t may contribute to dissolving the nether and polar regions

201= 0/1/10 Roger Lapthorn <rogerlap= thorn@gmail.com>

Fair comment= Mal, and one of these days I'll try QRS and see how it performs.

It should be possible to get a pretty good idea of the theoretical ran= ge limit for WSPR on 500kHz based on required S/N (which can be as low as -30dB= for WSPR), path loss calculations, ERP etc.. I shall be interested to see= what "the experts" say.

73s
Roger G3XBM

201= 0/1/10 mal hamilton <g3kevmal@talktalk.net>

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 the= trace been keyed it could have been identified.

I have been making this point for some time, avoid guesswork and speculation and use normal&nb= sp;CW or QRS CW

Regardless of erp transmitted the weakness is often at the RX end Little antenna Little= signal Big antenna Big signal and environment regarding noise.<= span lang=3DEN-GB>

RX loop antennas not optimised towards ur stn, these situations cannot be calculated just guessed and meaningles= s.

Get into QSO mode and see how far u can get in real time.<= /o:p>

&nb= sp;

G3KEV

&nb= sp;

----- Original Message -----

<= b>From: Roger Lapthorn <= /font>

To: rsgb_lf_group@blacksheep.org

Sent: Sunday, January 10, 2010 7:02 PM=

Subject: Re: LF: Link budget calculation or estimation of dist for given power= on WSPR

&nb= sp;

Certainly GM= 4SLV has a much lower noise floor than most stations on 500kHz Jim. I think he estimated about 10d= B 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 990k= ms 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 favo= urable 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

201= 0/1/10 James Cowburn <james.cowburn@virgin.net><= /p>

 Dear LF,

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

As it seems I ca= n 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 the= re a means for roughly estimating or indeed accurately calculating the Expe= cted Max Range (EMR) at that power setting and antenna configuration?

Clearly, there= are differences between separate Rx stations but if one knows the ratio be= tween 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 916k= m 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 th= e dB difference over known paths/signals?<= o:p>

Thanks in advanc= e 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://g3= xbm-qrp.blogspot.com/
http://www.g3xbm= .co.uk
http:/= /www.youtube.com/user/G3XBM
G3XBM    GQRP 1678      ISWL G11088

&nb= sp;

No virus found= in this incoming message.
Checked by AVG - www.avg.com
Version: 9.0.725 / Virus Database: 270.14.133/2612 - Release Date: 01/= 10/10 19:35:00

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