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[195.171.43.25]) by mx.google.com with ESMTP id ld3si10904924wic.76.2013.12.30.10.54.05 for ; Mon, 30 Dec 2013 10:54:06 -0800 (PST) Received-SPF: neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) client-ip=195.171.43.25; Authentication-Results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) smtp.mail=owner-rsgb_lf_group@blacksheep.org Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Vxhf9-0004xa-RC for rs_out_1@blacksheep.org; Mon, 30 Dec 2013 18:34:03 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Vxhf9-0004xR-8f for rsgb_lf_group@blacksheep.org; Mon, 30 Dec 2013 18:34:03 +0000 Received: from mout1.freenet.de ([195.4.92.91]) by relay1.thorcom.net with esmtps (UNKNOWN:AES256-GCM-SHA384:256) (Exim 4.77) (envelope-from ) id 1Vxhf6-0007X1-SA for rsgb_lf_group@blacksheep.org; Mon, 30 Dec 2013 18:34:02 +0000 Received: from [195.4.92.141] (helo=mjail1.freenet.de) by mout1.freenet.de with esmtpa (ID dl4yhf@freenet.de) (port 25) (Exim 4.80.1 #4) id 1Vxhf5-0008HO-TW for rsgb_lf_group@blacksheep.org; Mon, 30 Dec 2013 19:33:59 +0100 Received: from localhost ([::1]:51148 helo=mjail1.freenet.de) by mjail1.freenet.de with esmtpa (ID dl4yhf@freenet.de) (Exim 4.80.1 #4) id 1Vxhf5-00073R-Qm for rsgb_lf_group@blacksheep.org; Mon, 30 Dec 2013 19:33:59 +0100 Received: from mx4.freenet.de ([195.4.92.14]:35149) by mjail1.freenet.de with esmtpa (ID dl4yhf@freenet.de) (Exim 4.80.1 #4) id 1Vxhcd-0007Hu-CM for rsgb_lf_group@blacksheep.org; Mon, 30 Dec 2013 19:31:27 +0100 Received: from blfd-4d080c18.pool.mediaways.net ([77.8.12.24]:2312 helo=[192.168.178.21]) by mx4.freenet.de with esmtpsa (ID dl4yhf@freenet.de) (TLSv1:DHE-RSA-CAMELLIA256-SHA:256) (port 465) (Exim 4.80.1 #4) id 1Vxhcc-0001j7-Sl for rsgb_lf_group@blacksheep.org; Mon, 30 Dec 2013 19:31:27 +0100 Message-ID: <52C1BBFD.1040902@freenet.de> Date: Mon, 30 Dec 2013 19:31:25 +0100 From: wolf_dl4yhf User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <079a01cf057b$1af87300$50e95900$@comcast.net> In-Reply-To: <079a01cf057b$1af87300$50e95900$@comcast.net> X-Originated-At: 77.8.12.24!2312 X-Spam-Score: -0.1 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hello Jim, Stefan, and all, Jim's screenshot definitely shows the 'Alpha' (RSDN) signal. It's often difficult to tell which of the lines is the theoretic 'center' frequency - depending on how the various stations from Russia arrive at your QTH, the carriers may be in-phase or out of phase (i.e. cancel each other). [...] Content analysis details: (-0.1 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [195.4.92.91 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (dl4yhf[at]freenet.de) -0.1 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: 64bc660a83b79b15f4c44d2b2147e02d Subject: Re: LF: Frequency Check Content-Type: multipart/alternative; boundary="------------090608010200090306010001" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_30_40,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: 2330 This is a multi-part message in MIME format. --------------090608010200090306010001 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hello Jim, Stefan, and all, Jim's screenshot definitely shows the 'Alpha' (RSDN) signal. It's often difficult to tell which of the lines is the theoretic 'center' frequency - depending on how the various stations from Russia arrive at your QTH, the carriers may be in-phase or out of phase (i.e. cancel each other). But you can alternatively check the sampling rate by fractions of a Hz (or even a milli-Hertz) if NAA or NML is sufficiently strong at your QTH. I have checked both here (as far as the signal strength permits) against a GPSDO, and their center frequencies seem to be very accurate (like most of the European navy transmitters, too). How to use these VLF MSK transmitters to 'calibrate' the soundcard's sampling rate (in software) is described here: http://www.qsl.net/dl4yhf/speclab/frqcalib.htm#MSK_signals There should be two peaks in the spectrum shown in the calibrator's scope window. These are located symmetrically around the carrier frequency of the MSK signal, after the signal has been squared. The difference between the two narrow peaks depends on the transmitter's bitrate. All the best, Wolf . Am 30.12.2013 17:20, schrieb hvanesce: > > Stefan, > > My stable/accurate time reference (GPSDO) should arrive in two weeks; > in the meantime I am hoping to use 11904.76190 Hz (per your > suggestion, thanks) to assess my soundcard clock frequency offset. I > have been guessing (based on comparison with another uncalibrated but > stable oscillator) that the frequency offset of my soundcard gives > less than 1Hz error at 11904.76190 kHz. > > I have attached a screenshot captured over the last 24 hours, showing > a modulated signal centered at an indicated frequency (red marker) of > 11905.1884 which would have a 0.426 Hz offset from 11904.76190 Hz. > > The signal seems to be fading about 40dB on a 24-hour cycle, with a > minimum at ~ 2000 UT (clock times in my screen capture are Arizona > time, UT -- 7 hours). > > Could the modulated signal shown here be the 11904.76190 Hz signal? > > 73, Jim AA5BW > --------------090608010200090306010001 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit
Hello Jim, Stefan, and all,

Jim's screenshot definitely shows the 'Alpha' (RSDN) signal. It's often difficult to tell which of the lines is the theoretic 'center' frequency  - depending on how the various stations from Russia arrive at your QTH, the carriers may be in-phase or out of phase (i.e. cancel each other).

But you can alternatively check the sampling rate by fractions of a Hz (or even a milli-Hertz) if NAA or NML is sufficiently strong at your QTH. I have checked both here (as far as the signal strength permits) against a GPSDO, and their center frequencies seem to be very accurate (like most of the European navy transmitters, too).
How to use these VLF MSK transmitters to 'calibrate' the soundcard's sampling rate (in software) is described here:

http://www.qsl.net/dl4yhf/speclab/frqcalib.htm#MSK_signals

There should be two peaks in the spectrum shown in the calibrator's scope window. These are located symmetrically around the carrier frequency of the MSK signal, after the signal has been squared. The difference between the two narrow peaks depends on the transmitter's bitrate.

All the best,
  Wolf .

Am 30.12.2013 17:20, schrieb hvanesce:

Stefan,

 

My stable/accurate time reference (GPSDO) should arrive in two weeks; in the meantime I am hoping to use 11904.76190 Hz (per your suggestion, thanks) to assess my soundcard clock frequency offset. I have been guessing (based on comparison with another uncalibrated but stable oscillator) that the frequency offset of my soundcard gives less than 1Hz error at 11904.76190 kHz.

 

I have attached a screenshot captured over the last 24 hours, showing a modulated signal centered at an indicated frequency (red marker) of 11905.1884 which would have a 0.426 Hz offset from 11904.76190 Hz.

 

The signal seems to be fading about 40dB on a 24-hour cycle, with a minimum at ~ 2000 UT (clock times in my screen capture are Arizona time, UT – 7 hours).

 

Could the modulated signal shown here be the 11904.76190 Hz signal?

 

73,  Jim AA5BW


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