X-GM-THRID: 1196684404245296047 X-Gmail-Labels: rsgb lf X-Gmail-Received: 75eb4c7f96c92e28e4eb89bac3e7951fe54e6b82 Delivered-To: daveyxm@gmail.com Received: by 10.54.71.12 with SMTP id t12cs52835wra; Sat, 4 Mar 2006 11:25:16 -0800 (PST) Received: by 10.66.245.7 with SMTP id s7mr1961781ugh; Sat, 04 Mar 2006 11:25:16 -0800 (PST) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.gmail.com with ESMTP id c1si3905055ugf.2006.03.04.11.25.15; Sat, 04 Mar 2006 11:25:16 -0800 (PST) Received-SPF: neutral (gmail.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1FFcKJ-0001po-3G for rs_out_1@blacksheep.org; Sat, 04 Mar 2006 19:22:03 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1FFcKI-0001pf-MK for rsgb_lf_group@blacksheep.org; Sat, 04 Mar 2006 19:22:02 +0000 Received: from smtp801.mail.ukl.yahoo.com ([217.12.12.138]) by relay1.thorcom.net with smtp (Exim 4.51) id 1FFdpb-0000XP-Ex for rsgb_lf_group@blacksheep.org; Sat, 04 Mar 2006 20:58:43 +0000 Received: (qmail 72214 invoked from network); 4 Mar 2006 19:21:46 -0000 Received: from unknown (HELO LAPTOP) (peter.martinez@btinternet.com@81.159.156.65 with login) by smtp801.mail.ukl.yahoo.com with SMTP; 4 Mar 2006 19:21:45 -0000 Message-ID: <00fa01c63fc0$e082d860$0300a8c0@LAPTOP> From: "Peter Martinez" To: References: <01cd01c63d73$69bc4f80$0300a8c0@LAPTOP> <4407287F.8000306@freenet.de> <029801c63e22$bb20b190$0300a8c0@LAPTOP> <003a01c63e33$08290cc0$67b0fea9@lark> <02a101c63e36$cf0e6120$0300a8c0@LAPTOP> <7.0.0.10.2.20060302213743.0383a228@spin-it.com> <02b901c63e4c$38a127c0$0300a8c0@LAPTOP> <030401c63ea8$6a6b90e0$0300a8c0@LAPTOP> Date: Sat, 4 Mar 2006 19:21:45 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Spam-Score: -2.6 (--) X-Spam-Report: autolearn=ham,BAYES_00=-2.599 Subject: Re: LF: LORAN spurious emission levels Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: 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 Status: O X-Status: X-Keywords: X-UID: 6232 >From G3PLX: Some small corrections to the calculation of the erp of a LORAN line... The mean power of a LORAN transmitter is a little lower than I said. If the published peak power is P and the Group Repetition Interval (GRI) is G, then the mean power will be 74.88*P/G for a master station (9 pulses/group) and 66.56*P/G for a slave (8 pulses/group). For example the Lessay (G=6731) slave transmitters are radiating 2.45 kW mean power. Thanks to DF6NM for helping me to get this part more accurate. To simplify the calculation derived from the spectrum measurements I showed in my last posting, the mean erp of spectral lines around 136kHz can be calculated as 1.155e-4*M/G where M is the mean power calculated as above. This makes the spurii from the Lessay slaves (eg Rugby) about 42uW. (micro-watts). Because of the way the pulses interact, individual spectral lines may be up to 3dB higher than this, or they may cancel out completely at some frequencies - it would be too complicated to figure out exactly what should be the level of each individual spectral line and the above calculation is attempting to give an average level only. I am still not sure I believe that we can really hear signals this low in power! 73 Peter