Return-Path: Received: (qmail 53847 invoked from network); 13 Apr 2004 17:45:23 -0000 Received: from unknown (HELO ptb-mxscan02.plus.net) (212.159.14.236) by ptb-mailstore02.plus.net with SMTP; 13 Apr 2004 17:45:23 -0000 Received: (qmail 96143 invoked from network); 13 Apr 2004 17:45:22 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 Received: from ptb-mxcore02.plus.net (212.159.14.216) by ptb-mxscan02.plus.net with SMTP; 13 Apr 2004 17:45:14 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore02.plus.net with esmtp (Exim) id 1BDRyE-000OFi-I2 for dave@picks.force9.co.uk; Tue, 13 Apr 2004 17:45:14 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1BDRwr-0005C5-J6 for rs_out_1@blacksheep.org; Tue, 13 Apr 2004 18:43:49 +0100 Received: from [213.232.95.59] (helo=relay.salmark.net) by post.thorcom.com with esmtp (Exim 4.14) id 1BDRwq-0005Bw-UF for rsgb_lf_group@blacksheep.org; Tue, 13 Apr 2004 18:43:49 +0100 X-Fake-Domain: magneto.esoterica.pt Received: from magneto.esoterica.pt ([195.22.0.25]) by relay.salmark.net with esmtp (Exim 4.24) id 1BDRwn-0007Vi-O1 for rsgb_lf_group@blacksheep.org; Tue, 13 Apr 2004 18:43:45 +0100 X-Fake-Domain: Slave_13.esoterica.pt Received: from Slave_13.esoterica.pt (adsl-norte02-1-17.vianw.pt [80.172.144.17]) by magneto.esoterica.pt (8.12.11/8.12.11) with ESMTP id i3DHhgJI013161 for ; Tue, 13 Apr 2004 18:43:43 +0100 Message-Id: <5.2.0.9.2.20040413162356.01c63ef0@pop.vianw.pt> X-Sender: nx4ywv@pop.vianw.pt X-Mailer: QUALCOMM Windows Eudora Version 5.2.0.9 Date: Tue, 13 Apr 2004 17:43:36 +0000 To: rsgb_lf_group@blacksheep.org From: Brian Rogerson Mime-Version: 1.0 X-Spam-Score: 0.0 (/) Subject: LF: CT<>ZL Content-Type: text/plain; charset=us-ascii; format=flowed X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none 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-PN-SPAMFiltered: yes X-Spam-Rating: 1 Content-transfer-encoding: 8bit Hello all, Further to the comment by Marek SQ5BPM ""But, surprisingly, the path from Greece, southern Spain and Portugal to New Zealand is ca. 3/4 over the sea. Especially Portugal is interesting as the path is very close to 20000km and is mostly over the sea in both directions. Shortest paths on a sphere are not very intuitive hi."" I would like to draw attention to another factor which comes into play at least in the case of the Iberian Peninsula. Porto is almost exactly diametrically opposite to Wellington. The sunrise in Porto is almost exactly the same and locked to the sunset time in Wellington, giving around 5m greyline, and the sunset in Porto is similarly locked to the sunrise in Wellington giving no greyline at all. This I believe to be true for the whole yearly cycle. If a significant dark path is necessary as it would appear from the recently reported captures of DCF39 in New Zealand, I postulate that it is not possible under "normal" conditions to achieve longwave communication over the ~20,000km. However all is not lost as previous experience with 160m showed that sporadic but very infrequent communication was possible over this path and at signal strengths that need some explaining. Perhaps someone with better understanding of this phenomenon (and better maths than mine) could calculate the diameter of the effective "cone of silence" around diametrically situated stations and suggest a strategy to exploit whatever phenomenon assisted communication on 160m. Please discuss. Plots of Sunrise and Sunset are below. http://homepage.esoterica.pt/~brian/NZSunRiseSet_1.htm http://homepage.esoterica.pt/~brian/NZSunRiseSet_2.htm 73, Brian CT1DRP