Return-Path: <owner-rsgb_lf_group@blacksheep.org> Received: from rly-de06.mx.aol.com (rly-de06.mail.aol.com [172.19.170.142]) by air-de02.mail.aol.com (v125.7) with ESMTP id MAILINDE021-4e24ab4c973360; Sat, 19 Sep 2009 08:07:27 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-de06.mx.aol.com (v125.7) with ESMTP id MAILRELAYINDE065-4e24ab4c973360; Sat, 19 Sep 2009 08:07:17 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Moyhj-0002xj-DH for rs_out_1@blacksheep.org; Sat, 19 Sep 2009 13:06:15 +0100 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Moyhi-0002xa-SC for rsgb_lf_group@blacksheep.org; Sat, 19 Sep 2009 13:06:14 +0100 Received: from smtp821.mail.ird.yahoo.com ([217.146.188.236]) by relay3.thorcom.net with smtp (Exim 4.63) (envelope-from <james.moritz@btopenworld.com>) id 1MoyhZ-0000h7-5F for rsgb_lf_group@blacksheep.org; Sat, 19 Sep 2009 13:06:07 +0100 Received: (qmail 96679 invoked from network); 19 Sep 2009 12:05:59 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btopenworld.com; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=ny/uplPboRYuMNlTtC583eU5pXE9jnsTPOcUNL3MIZV4L13319LOo1O6FNIYO+sVeC9nSqfwhoAZvbjuYpngtz25fUkwzQPEnaox6dswp3v1kNTPjTY3K/+1nlGrevE4oYTp8q1jahwxV/v9gCSROBk6ZoPtzr/+JiEZ5vL58Fk= ; Received: from unknown (HELO JimPC) (james.moritz@86.176.84.176 with login) by smtp821.mail.ird.yahoo.com with SMTP; 19 Sep 2009 12:05:59 -0000 X-Yahoo-SMTP: qKIhhNCswBB2TTHr2BORWcGGR2mpopxhCcunGIxpCKQYiG07Q7UOhNo- X-YMail-OSG: HIFWC1cVM1mRDTVBODuExNJ18lvf51HyEL79SJEdGsm6NdqcnsTuER7yuiqwGNztcBlXC_8k78ncTvuyTZkqxZqNxzignbaGIqtJTWRqwllX2jIF2gYnnKL8m0TCg4FSR0aggOdAs.q4LGOLartAM_Ef7oQjJ3XYRkPYtpcwykEnSFMesPreNy8.Ll8rK9HHrGH34qhaZbwWBhb31aP9VosAky8YFd_5ZYmsCZZmAOhewQr9tXc- X-Yahoo-Newman-Property: ymail-3 Message-ID: <D812D7F98DBA499EB733CCE0B5F71C49@JimPC> From: "James Moritz" <james.moritz@btopenworld.com> To: <rsgb_lf_group@blacksheep.org> References: <fc7eccec0909190406r6b596274h8e84feed93216356@mail.gmail.com> In-Reply-To: <fc7eccec0909190406r6b596274h8e84feed93216356@mail.gmail.com> Date: Sat, 19 Sep 2009 13:05:59 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6001.18000 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: LF: Re: 'JNT Dual purpose beacons Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original 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=0.1 required=5.0 tests=MISSING_OUTLOOK_NAME 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 Dear Andy, I would suggest a frequency between 503.825 and 503.900, to avoid the QRM around 504kHz some people experience, and give a bit of tolerance for receiver frequency errors, which are sometimes suprisingly large. For some reason, the frequencies below 503.9 seem to be less widely used. But since there are only about half a dozen stations transmitting in this mode, there is plenty of space. A 25% or 33% duty cycle seems to be frequent enough to catch most "openings" - probably less would be OK. As for power, I would suggest running as much as possible - monitoring signal level of a strong beacon is easier than a weak one, and a relatively high power will give the greatest chance of being received by the maximum number of stations under the maximum range of conditions. You could argue that the presence of a "strong" beacon would sometimes prevent reception of very weak signals nearby in frequency, but since this only can happen 25% or 33% of the time, and the signal is not so strong at a few 100 mW ERP, it is probably not a serious objection in practice. Cheers, Jim Moritz 73 de M0BMU