Return-Path: Received: from rly-mg01.mx.aol.com (rly-mg01.mail.aol.com [172.20.83.107]) by air-mg05.mail.aol.com (v125.7) with ESMTP id MAILINMG053-9f44ab4b747392; Sat, 19 Sep 2009 06:50:11 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-mg01.mx.aol.com (v125.7) with ESMTP id MAILRELAYINMG016-9f44ab4b747392; Sat, 19 Sep 2009 06:49:44 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1MoxV0-0002FN-I8 for rs_out_1@blacksheep.org; Sat, 19 Sep 2009 11:49:02 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1MoxV0-0002FE-0H for rsgb_lf_group@blacksheep.org; Sat, 19 Sep 2009 11:49:02 +0100 Received: from mtaout03-winn.ispmail.ntl.com ([81.103.221.49]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1MoxTq-0006Zw-Ca for rsgb_lf_group@blacksheep.org; Sat, 19 Sep 2009 11:47:51 +0100 Received: from know-smtpout-1.server.virginmedia.net ([62.254.123.1]) by mtaout03-winn.ispmail.ntl.com (InterMail vM.7.08.04.00 201-2186-134-20080326) with ESMTP id <20090919104846.XWMD5579.mtaout03-winn.ispmail.ntl.com@know-smtpout-1.server.virginmedia.net> for ; Sat, 19 Sep 2009 11:48:46 +0100 Received: from [82.3.250.15] (helo=jimdesk) by know-smtpout-1.server.virginmedia.net with esmtp (Exim 4.63) (envelope-from ) id 1MoxUi-0003wE-HC for rsgb_lf_group@blacksheep.org; Sat, 19 Sep 2009 11:48:46 +0100 From: "James Cowburn" To: References: <9afca2640909181501s4ea78076wf335f218ab07a106@mail.gmail.com> <9afca2640909190053uc3188c8ja0529072f1b42955@mail.gmail.com> <65021672466E4DA891D8CC98B984A4AA@JimPC> <9afca2640909190252s23c96e1bh33bdcf0178efc277@mail.gmail.com> Date: Sat, 19 Sep 2009 11:48:35 +0100 Message-ID: <00d901ca3916$bf0e4e50$0217aac0@jimdesk> MIME-Version: 1.0 X-Mailer: Microsoft Office Outlook 11 In-Reply-To: <9afca2640909190252s23c96e1bh33bdcf0178efc277@mail.gmail.com> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3350 Thread-Index: Aco5DwezWIGrIHLfRgWXQky/Pr+kygAB6mJg X-Cloudmark-Analysis: v=1.0 c=1 a=F3M5lZpKAAAA:8 a=MDZQaXdsAAAA:8 a=fnYqA7hvAAAA:8 a=j6Q1dnSHAAAA:8 a=c9686yxebVDfaStuVN8A:9 a=Zr-ABE62lEIBq7gns4EA:7 a=3rN5BWa_otXXCgrAhhHuyUgLlpQA:4 a=wk6s2zzMB60A:10 a=nhn505YfawQA:10 a=gA6IeH5FQcgA:10 a=NWVoK91CQyQA:10 a=CZuRg4M7E2tkl-Oz:21 a=4gp-xyRNfB7ZcTPp:21 a=SSmOFEACAAAA:8 a=jTN8b7eJIq6Gp5Q1JbIA:9 a=yZu226FD8RoLjE1wVPMA:7 a=kRSBIHALRRkgVtSpr50PzcIynO4A:4 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: RE: 500kHz QRPp WSPR overnight Content-Type: multipart/alternative; boundary="----=_NextPart_000_00DA_01CA391F.20D2B650" 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-IP: 193.82.116.20 ------=_NextPart_000_00DA_01CA391F.20D2B650 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit My wife goes shopping.works for her!! With best regards Jim Dr. James Cowburn _____ From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Roger Lapthorn Sent: 19 September 2009 10:52 To: rsgb_lf_group@blacksheep.org Subject: Re: LF: RE: 500kHz QRPp WSPR overnight Dear Jim (et al), Thanks for this interesting analysis. It does indeed suggest plenty of scope for improvement in the coming months. As I've said several times in the last week, I'm gobsmacked that anyone, apart from G6ALB 3kms away, is able to hear me with the set-up I have. The 500kHz WSPR beacon will run one more time overnight tonight then it will be off for 2-3 weeks. My wife is wanting her dressing table back as the tiny ATU is sitting on it and tuning is very sharp; every time she puts anything down I have to check the antenna current is peaked :-)) You know I'm like a kid: I get so excited looking at the spots and thinking about gradually making improvements and seeing my coverage extend on 500kHz. My wife just humours me! 73s Roger G3XBM 2009/9/19 James Moritz Dear Roger, LF Group, It is interesting to make an estimate of what G3XBM's ERP might be... The noise level at M0BMU during relatively quiet daytime conditions I estimate to be of the order of 3uV/m in the 2.5kHz WSPR reference bandwidth. The reported SNR gets up to about -25dB, making the signal level from G3XBM about 0.18uV/m. ERP = (Ed)^2 / 49; with E = 0.18 x 10e-6, d = 69000m , ERP is about 3uW with only "geometric spreading" propagation losses. But there is some additional reduction in field strength due to ground wave propagation losses, perhaps 3dB with "good" ground, so the ERP would then become about 6uW. Diffraction losses due to the curvature of the earth are negligible at this distance. Obviously, this could be +/- several dB due to various uncertainties, but should be of the right order of magnitude. Plenty of potential for improvement then! Cheers, Jim Moritz 73 de M0BMU -- ------------------------------------------------------------- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk G3XBM GQRP 1678 ISWL G11088 ------=_NextPart_000_00DA_01CA391F.20D2B650 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

My wife goes sh= opping…works for her!!

 

With best regar= ds

 

 

Jim=

 

 

Dr. James Cowbu= rn

 

From: owner-rsgb_lf_group@blac= ksheep.org [mailto:owner-= rsgb_lf_group@blacksheep.org] On Behalf Of Roger Lapthorn
Sent: 19 September 2009= 10:52
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: RE: 50= 0kHz QRPp WSPR overnight

 

Dear Jim (et al= ),

Thanks for this interesting analysis. It does indeed suggest plenty= of scope for improvement in the coming months.

As I've said several times in the last week, I'm gobsmacked that anyon= e, apart from G6ALB 3kms away, is able to hear me with the set-up I have. The= 500kHz WSPR beacon will run one more time overnight tonight  then it wil= l be off for 2-3 weeks. 

My wife is wanting her dressing table back as the tiny ATU is sitting= on it and tuning is very sharp; every time she puts anything down I have to chec= k the antenna current is peaked :-))

You know I'm like a kid: I get so= excited looking at the spots and thinking about gradually making impro= vements and seeing my coverage extend on 500kHz.

My wife just humours me!

73s
Roger G3XBM

2009/9/19 James Moritz <james.moritz@btopenworld.com>

Dear Roger, LF= Group,

It is interesting to make an estimate of what G3XBM's ERP might be...<= br>
The noise level at M0BMU during relatively quiet daytime conditions I= estimate to be of the order of 3uV/m in the 2.5kHz WSPR reference bandwidth. Th= e reported SNR gets up to about -25dB, making the signal level from G3XB= M about 0.18uV/m.

ERP =3D (Ed)^2 / 49; with E =3D 0.18 x 10e-6, d =3D 69000m , ERP is ab= out 3uW with only "geometric spreading" propagation losses. But there is= some additional reduction in field strength due to ground wave propagation= losses, perhaps 3dB with "good" ground, so the ERP would then become= about 6uW. Diffraction losses due to the curvature of the earth are negligib= le at this distance.

Obviously, this could be +/- several dB due to various uncertainties,= but should be of the right order of magnitude. Plenty of potential for imp= rovement then!

Cheers, Jim Moritz
73 de M0BMU




--
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http://g3xbm-qrp.blogspot.c= om/
http://www.g3xbm.co.uk
G3XBM    GQRP 1678      ISWL G11088

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