Return-Path: Received: from mtain-ma05.r1000.mx.aol.com (mtain-ma05.r1000.mx.aol.com [172.29.96.13]) by air-db05.mail.aol.com (v129.4) with ESMTP id MAILINDB052-861f4d83cb2b12a; Fri, 18 Mar 2011 17:14:19 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma05.r1000.mx.aol.com (Internet Inbound) with ESMTP id E867B38000337; Fri, 18 Mar 2011 17:14:17 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Q0gz4-0006G3-Vd for rs_out_1@blacksheep.org; Fri, 18 Mar 2011 21:13:22 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Q0gz4-0006Fu-EU for rsgb_lf_group@blacksheep.org; Fri, 18 Mar 2011 21:13:22 +0000 Received: from mout2.freenet.de ([195.4.92.92]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Q0gz3-0006yH-MP for rsgb_lf_group@blacksheep.org; Fri, 18 Mar 2011 21:13:22 +0000 Received: from [195.4.92.10] (helo=0.mx.freenet.de) by mout2.freenet.de with esmtpa (ID dl4yhf@freenet.de) (port 25) (Exim 4.72 #3) id 1Q0gz2-0001Y0-WD for rsgb_lf_group@blacksheep.org; Fri, 18 Mar 2011 22:13:20 +0100 Received: from blfd-4d083f0e.pool.mediaways.net ([77.8.63.14]:1356 helo=[192.168.0.101]) by 0.mx.freenet.de with esmtpsa (ID dl4yhf@freenet.de) (TLSv1:CAMELLIA256-SHA:256) (port 465) (Exim 4.72 #3) id 1Q0gz2-0006eZ-LU for rsgb_lf_group@blacksheep.org; Fri, 18 Mar 2011 22:13:20 +0100 Message-ID: <4D83CAEE.2060305@freenet.de> Date: Fri, 18 Mar 2011 22:13:18 +0100 From: wolf_dl4yhf User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.2.15) Gecko/20110303 Thunderbird/3.1.9 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: In-Reply-To: X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: Re: Frequency Stability Content-Type: text/plain; charset=ISO-8859-1; format=flowed 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 x-aol-global-disposition: G x-aol-sid: 3039ac1d600d4d83cb29770e X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Content-Transfer-Encoding: quoted-printable X-Mailer: Unknown (No Version) Hi Ken, Martin, and group, I'd say yes... 8970 Hz * 2e-9 =3D circa 18 =B5Hz resolution, that's fine. Even better than most soundcard's short-term oscillator stability, and=20 the dreadful effects caused by the soundcard driver permits. Even if Radio 4 may suffer from daytime/nighttime propagation effects=20 (depending on your distance to the transmitter), it will be good enough even for "ridiculously long FFTs". Alternatively, you could go for an el-cheapo GPS receiver with=20 one-pulse-per-second output. The next version of Spectrum Lab will=20 support that as reference input, quite similar to what Paul Nicholson is= =20 using. I am using a Garmin GPS 18x VLC, available for a fair price at RS= =20 components. The performance (jitter) is not spectacularly low ...there=20 are "better" GPS receivers out there..., but it should be fine for our=20 applications. And the receiver is very sensitice, I have it running=20 indoors, with a ceiling and the roof above me, still gives perfect lock=20 (9 to 11 satellites in view). All the best, Wolf . Am 18.03.2011 21:09, schrieb Martin Evans: > > > > To All VLF. > Is the following frequency stability sufficient for Spectrum Lab: > > 1MHz and 10MHz derived from Radio 4 198 kHz Accuracy 2 parts in10-8=20 > over 1 sec,2 parts in10-9 over 10secs. > > > 73s > > Ken > > M0KHW IO91TV > > ############################# > > You're after the Quartzlock unit on eBay eh, Ken. > > I'm watching that too. > > Martin GW3UCJ > > > > >