X-GM-THRID: 1234634547594046371 X-Gmail-Labels: rsgb lf Delivered-To: daveyxm@gmail.com Received: by 10.35.22.8 with SMTP id z8cs280512pyi; Tue, 24 Apr 2007 11:53:31 -0700 (PDT) Received: by 10.114.168.1 with SMTP id q1mr3343523wae.1177440811004; Tue, 24 Apr 2007 11:53:31 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.google.com with ESMTP id 13si1470158ugb.2007.04.24.11.53.27; Tue, 24 Apr 2007 11:53:30 -0700 (PDT) Received-SPF: neutral (google.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) DomainKey-Status: bad (test mode) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1HgQ67-0005TY-Dm for rs_out_1@blacksheep.org; Tue, 24 Apr 2007 19:50:43 +0100 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1HgQ66-0005TP-GY for rsgb_lf_group@blacksheep.org; Tue, 24 Apr 2007 19:50:42 +0100 Received: from smtp809.mail.ird.yahoo.com ([217.146.188.69]) by relay2.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1HgQ65-000340-82 for rsgb_lf_group@blacksheep.org; Tue, 24 Apr 2007 19:50:42 +0100 Received: (qmail 39166 invoked from network); 24 Apr 2007 18:50:35 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btopenworld.com; h=Received:X-YMail-OSG:Received:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=ASkQtjKvJ+HsA7p6ZonS3EufPtWRIHqrKZvFUZLalxrnw5uRyu36okwbSh/mlqR4JwVrU/GoSlrbLt6MbfLP6lSo20dmpIYx2JA2oUSJ42/fs8B2axsrDVpb+bKj696IQYlu5hzZ3bO6ATJ/9xhxv9XHFIHldpOydSIz2gfbEOo= ; Received: from unknown (HELO w4o8m9) (james.moritz@btopenworld.com@81.131.10.24 with login) by smtp809.mail.ird.yahoo.com with SMTP; 24 Apr 2007 18:50:34 -0000 X-YMail-OSG: 18uKjhEVM1laEj2cnfov5HOkC50VWFRECgRzUcKy1DXIoVLXSPqDd0eJ1vp8dn623zEeeUAOGVW7huMmn9Ba2HQ5QSraiiCVLtHE6IQhDrmdzgQXevYeMwk7IHY- Received: from 127.0.0.1 (AVG SMTP 7.5.463 [269.5.10/774]); Tue, 24 Apr 2007 19:51:08 +0100 Message-ID: <001701c786a1$84fa47c0$180a8351@w4o8m9> From: "James Moritz" To: References: Date: Tue, 24 Apr 2007 19:51:07 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 DomainKey-Status: good (testing) X-Spam-Score: -0.6 (/) X-Spam-Report: autolearn=disabled,AWL=-0.559,HTML_MESSAGE=0.001 Subject: LF: Re: 500kHz Content-Type: multipart/alternative; boundary="----=_NextPart_000_0014_01C786A9.E684B400" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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 Status: O X-Status: X-Keywords: X-UID: 1896 This is a multi-part message in MIME format. ------=_NextPart_000_0014_01C786A9.E684B400 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dear Andy, LF Group, At the moment, most stations in the UK seem to find an adequate SNR so = they can work each other by conventional means. I expect this will = change a lot when 500kHz becomes more widely available in other = countries. It looks like one of the problems to be solved in order to = make good use of the band for longer distance contacts is the QSB.The = period between fades seems to be a few minutes - which is awkward for CW = operating, since the station you are trying to work dissapears and = reappears with a period of about 1 over, with the likely results of both = stations losing each other, and either trying to transmit or receive = simultaneously, not knowing what the other is doing. It is also awkward = for QRSS and other "slow" modes, because you will inevitably loose a = fair proportion of characters due to the fades. I think for long = distance contacts, there is scope for a mode like "Wolf" where a signal = with a lot of redundancy is integrated over a fairly long period of = time. It should be easier to implement more complicated modulation = schemes thanks to the lower power requirements. At M0BMU at the moment I am getting things ready for another series of = antenna and field strength measurements, extending the experiments I did = on 73k and 136k some years back. This time I hope it will be 136k, 500k = and maybe 1.8MHz too, to fill in the gaps in the spectrum.The TX and = antenna arangements seem to be quite reproducible and stable here now, = so I am working on updating my mobile FS measurement system to include = the new frequencies. It's a pity 73kHz was discontinued, as now the band = is eerily quiet and free from QRM. Wonder what they wanted it for? Cheers, Jim Moritz 73 de M0BMU ----- Original Message -----=20 From: Andy Talbot=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, April 24, 2007 1:52 PM Subject: LF: 500kHz I've been away from the LF scene for some time, and haven't even been = reading the postings recently, so know nothing of what is going on on = 0.5MHz. ------=_NextPart_000_0014_01C786A9.E684B400 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Dear Andy, LF Group,
 
At the moment, most stations in = the UK seem to=20 find an adequate SNR so they can work each other by conventional means. = I expect=20 this will change a lot when 500kHz becomes more widely available in = other=20 countries. It looks like one of the problems to be solved in order = to make=20 good use of the band for longer distance contacts is the QSB.The period between fades seems to be a few = minutes=20 - which is awkward for CW operating, since the station you are = trying to=20 work dissapears and reappears with a period of about 1 over, with=20 the likely results of both stations losing each other, and either = trying to=20 transmit or receive simultaneously, not knowing what the other is doing. = It is=20 also awkward for QRSS and other "slow" modes, because you will = inevitably loose=20 a fair proportion of characters due to the fades. I think for long = distance=20 contacts, there is scope for a mode like "Wolf" where a signal with = a lot=20 of redundancy is integrated over a fairly long period of time. It should = be=20 easier to implement more complicated modulation schemes thanks to the = lower=20 power requirements.
 
At M0BMU at the moment I am getting = things ready=20 for another series of antenna and field strength measurements, = extending=20 the experiments I did on 73k and 136k some years back. This time I hope = it will=20 be 136k, 500k and maybe 1.8MHz too, to fill in the gaps in the = spectrum.The TX=20 and antenna arangements seem to be quite reproducible and stable here = now, so I=20 am working on updating my mobile FS measurement system to include the = new=20 frequencies. It's a pity 73kHz was discontinued, as now the band is = eerily quiet=20 and free from QRM. Wonder what they wanted it for?
 
Cheers, Jim Moritz
73 de M0BMU
----- Original Message -----
From:=20 Andy Talbot
Sent: Tuesday, April 24, 2007 = 1:52=20 PM
Subject: LF: 500kHz


I've been away from the LF scene for some time, and haven't = even been=20 reading the postings recently, so know nothing of what is going on on=20 0.5MHz.
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