Return-Path: X-Spam-DCC: paranoid 1102; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,HTML_40_50, HTML_MESSAGE autolearn=unavailable version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id s8QIBOwc010890 for ; Fri, 26 Sep 2014 20:11:26 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1XXZvA-0000mK-SS for rs_out_1@blacksheep.org; Fri, 26 Sep 2014 19:07:08 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1XXZvA-0000mB-Fx for rsgb_lf_group@blacksheep.org; Fri, 26 Sep 2014 19:07:08 +0100 Received: from omr-m07.mx.aol.com ([64.12.143.81]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.82) (envelope-from ) id 1XXZv7-0004Zn-Sy for rsgb_lf_group@blacksheep.org; Fri, 26 Sep 2014 19:07:07 +0100 Received: from mtaout-aai02.mx.aol.com (mtaout-aai02.mx.aol.com [172.27.2.98]) by omr-m07.mx.aol.com (Outbound Mail Relay) with ESMTP id 5268B70035457 for ; Fri, 26 Sep 2014 14:07:02 -0400 (EDT) Received: from White (unknown [95.91.239.181]) by mtaout-aai02.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id ADDDC38000081 for ; Fri, 26 Sep 2014 14:06:58 -0400 (EDT) Message-ID: <9D662F61104243F4AF24BC4509491D69@White> From: "Markus Vester" To: References: <8D1A71FA0A4AA26-1C58-173EE@webmail-m296.sysops.aol.com> <8D1A7329934A80E-DB8-18B19@webmail-va078.sysops.aol.com> <54255DF2.9050706@gmail.com> Date: Fri, 26 Sep 2014 20:05:01 +0200 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 12.0.1606 X-MimeOLE: Produced By Microsoft MimeOLE V12.0.1606 x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20140625; t=1411754822; bh=Viw1dnw5DfRGCTOuU5hB9ev7ZyU0mcOfrtW0hSObeFU=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=SZgRf37QUJ5bECMtot16QvjmmDPsZgRxFiAGS9xlu2B8XZIUUE7RHmGC3AeFSUunn BxOxebeZkNjjndVO+qH6LWp4Ms4n8g7iv5D3BG34eO5x7GbLWPjUx7q7FkxNAZ6RqO JckSafC0yF5DQ4zVAa93F4XIznitx0mOeU8XExEw= x-aol-sid: 3039ac1b02625425ab425a2d X-AOL-IP: 95.91.239.181 X-Scan-Signature: 78d45eae26b8e09cb3b944588f353c28 Subject: Re: LF: European Loran in Tasmania Content-Type: multipart/alternative; boundary="----=_NextPart_000_0004_01CFD9C5.279AE100" 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: RO X-Status: X-Keywords: X-UID: 494 Dies ist eine mehrteilige Nachricht im MIME-Format. ------=_NextPart_000_0004_01CFD9C5.279AE100 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Stefan, guess it depends on what you want to achieve. Your signal strength is = above average, and some dashes have already been detected several times = in Tasmania. You may now be aiming to convey a complete callsign or a = message. Considering that an opening will often last less than an hour, = DFCW 600 may already be too slow for this purpose. Although, as Paul = Nicholson recently pointed out, visual QRSS or DFCW may not be the most = efficient schemes in terms of data throughput at limited SNR. On the other hand, others with more limited ERP would probably be very = happy with a simple and unique overseas detection of the presence of = their signal. For this purpose, very long carriers and half-milliHz = detection bandwidth (aka "6000") have proven extremely valuable at VLF. = My point was that such a narrow bandwidth would still be supported by = the stability of an LF long-distance path. =20 How different is 100 kHz from 137? I think that although there may be = some differences (eg. less groundwave absorption and smaller phase = variability at lower frequency), the general behaviour seems quite = similar. Although I havent attempted a proper quantitative analysis, the = strength of 100 kHz Loran signals eg from Japan or America seemed to be = fairly well correlated with propagation conditions observed by LF = amateurs or DCF39. Best 73, Markus (DF6NM) From: DK7FC=20 Sent: Friday, September 26, 2014 2:37 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: European Loran in Tasmania Hello Markus, Edgar, LF,=20 Does that mean you would recommend to try slower DFCW modes than 180 ? = Maybe 600, like in the old VLF days? What could be the difference in propagartion between 2200m and 3000m ? 73, Stefan Am 26.09.2014 01:50, schrieb Markus Vester:=20 Last night, Edgar J. Twining in Moonah, Tasmania has successfully = picked up several Loran-C signals from the other side of the world. He = was using an E-field antenna connected to his Excalibur receiver, tuned = to a 6 kHz band around 100 kHz. For phase and timing reference, the = rising edge of 1pps pulses from a GPS device was capacitively injected = to the antenna line. In the wee hours between 18 and 19:50 UT, Edgar = produced a set of four 20-minute recordings, which were then = postprocessed here using my homebrew "LoranView" averaging software.=20 Attached image is the result using one-minute averaging. Each of the = 40 columns corresponds to the repetition rate and delay of a single = Loran station, dual rated stations appear twice. The order of slots is = generally west to east, with the exception of the GRI 7950 chain at the = right which has been added later. Horizontal timescale within each slot = is equivalent to the 12 kHz samplerate, ie. 83 us per pixel or 2 ms in = each slot. Vertical scale is one pixel per minute, from 18 (bottom) to = 19:50 UT (top), with three 11 minute interruptions due to the gaps = between files. Colour hue corresponds to received carrier phase, = referenced to the 1pps pulse shown in the leftmost slot. The slots for = the Chinese navigation stations are empty as these have been off air for = a couple of days, presumably for maintenance.=20 Edgar's is getting solid traces even from his furthest station, Lessay = at 17521 km, which is radiating 250 kW peak or about 3 kW average power = on each of the two rates. As all Loran stations share a common frequency = band, the fact that he doesn't have nearby stations probably helps to = reduce crossrate clutter, allowing him to fully exploit the sensitivity = of his excellent receive setup.=20 Interestingly, the colour of the very distant traces is changing only = slowly, indicating phase stability of the path on the order of an hour = or so. This confirms that sub-milliHz bandwidths can indeed be useful to = enhance slow weak-signal communication on 137 kHz. Best 73, Markus (DF6NM) ... ------=_NextPart_000_0004_01CFD9C5.279AE100 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Stefan,
 
guess it depends on what you want to=20 achieve. Your signal strength is above average, and some dashes = have=20 already been detected several times in Tasmania. You may now be = aiming=20 to convey a complete callsign or a message. Considering=20 that an opening will often last less than an hour, DFCW = 600 may=20 already be too slow for this purpose. Although, as Paul=20 Nicholson recently pointed out, visual QRSS or DFCW may = not=20 be the most efficient schemes in terms of data=20 throughput at limited SNR.
 
On the other hand, others with more=20 limited ERP would probably be very happy with a = simple and unique overseas detection of the presence of their=20 signal. For this purpose, very long carriers and half-milliHz = detection=20 bandwidth (aka "6000") have proven extremely valuable at=20 VLF. My point was that such a narrow bandwidth would = still be=20 supported by the stability of an LF long-distance=20 path.  
 
How different is 100 = kHz from 137? I=20 think that although there may be some differences (eg. less groundwave=20 absorption and smaller phase variability at lower frequency), the = general=20 behaviour seems quite similar. Although I havent attempted a proper = quantitative=20 analysis, the strength of 100 kHz Loran signals eg from Japan or America = seemed=20 to be fairly well correlated with propagation = conditions observed=20 by LF amateurs or DCF39.
 
Best 73,
Markus (DF6NM)
 
 

From: DK7FC
Sent: Friday, September 26, 2014 2:37 PM
Subject: Re: LF: European Loran in = Tasmania

Hello = Markus, Edgar,=20 LF,

Does that mean you would recommend to try slower DFCW modes = than 180=20 ? Maybe 600, like in the old VLF days?
What could be the difference = in=20 propagartion between 2200m and 3000m ?

73, Stefan

Am = 26.09.2014=20 01:50, schrieb Markus Vester:=20
Last night, Edgar J. Twining in Moonah, Tasmania has = successfully=20 picked up several Loran-C signals from the other side of the=20 world. He was using an E-field antenna connected to=20 his Excalibur receiver, tuned to a 6 kHz band around 100 = kHz. For=20 phase and timing reference, the rising edge of 1pps pulses from a GPS = device=20 was capacitively injected to the antenna line. In the wee hours=20 between 18 and 19:50 UT, Edgar produced a set of four=20 20-minute recordings, which were then = postprocessed here=20 using my homebrew "LoranView" averaging software.
 
Attached image is the result using one-minute = averaging. Each of the=20 40 columns corresponds to the repetition rate and delay of a = single Loran=20 station, dual rated stations appear twice. The order of slots is=20 generally west to east, with the exception of the GRI 7950 chain at = the right=20 which has been added later. Horizontal timescale within each slot=20 is equivalent to the 12 kHz samplerate, ie. 83 us per = pixel or=20 2 ms in each slot. Vertical scale is one = pixel per=20 minute, from 18 (bottom) to 19:50 UT (top), with three 11 minute=20 interruptions due to the gaps between files. Colour hue = corresponds to received carrier phase, referenced to the = 1pps pulse shown=20 in the leftmost slot. The slots for the Chinese navigation stations = are empty=20 as these have been off air for a couple of days, presumably for = maintenance.=20
 
Edgar's is getting solid traces even from his furthest station, = Lessay at=20 17521 km, which is radiating 250 kW peak or about 3 kW = average power=20 on each of the two rates. As all Loran stations share a = common=20 frequency band, the fact that he doesn't have nearby stations = probably=20 helps to reduce crossrate clutter, allowing him to fully exploit = the=20 sensitivity of his excellent receive setup.
 
Interestingly, the colour of the very distant traces is = changing=20 only slowly, indicating phase stability of the path on the order of an = hour or=20 so. This confirms that sub-milliHz bandwidths can=20 indeed be useful to enhance slow weak-signal communication = on 137=20 kHz.
 
Best 73,
Markus (DF6NM)
 
...
------=_NextPart_000_0004_01CFD9C5.279AE100--