Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-db02.r1000.mx.aol.com (Internet Inbound) with ESMTP id A90D73800013B; Thu, 1 Sep 2011 18:38:29 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QzFtG-0005Gb-4U for rs_out_1@blacksheep.org; Thu, 01 Sep 2011 23:37:42 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QzFtF-0005GS-D3 for rsgb_lf_group@blacksheep.org; Thu, 01 Sep 2011 23:37:41 +0100 Received: from mail-bw0-f43.google.com ([209.85.214.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QzFtC-00027t-TK for rsgb_lf_group@blacksheep.org; Thu, 01 Sep 2011 23:37:41 +0100 Received: by bkbzv15 with SMTP id zv15so3364933bkb.16 for ; Thu, 01 Sep 2011 15:37:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=UMg/VSN0DYpY/L+96cz2GprecMTiKPkqLDW6Kib/KHA=; b=Kpv8oq6bbzueWTPMmc7RDzcCpT5CCLvXBuAdTU9s2NBvv7kcKaDCOPf7GRe7hDmz8V 3QjYj4xGlq0lQjnxJqCj7swqxoYNF8Syz1kOhrWIJbMno+bb/c7h2rP0/4QCshcUh77Y cV8R3WfeCSTGlbC0m5Hs9MmUP1NRymU8HOL9s= MIME-Version: 1.0 Received: by 10.204.135.1 with SMTP id l1mr190987bkt.270.1314916652506; Thu, 01 Sep 2011 15:37:32 -0700 (PDT) Received: by 10.204.115.83 with HTTP; Thu, 1 Sep 2011 15:37:32 -0700 (PDT) In-Reply-To: References: Date: Fri, 2 Sep 2011 01:37:32 +0300 Message-ID: From: Chris 4X1RF To: rsgb_lf_group@blacksheep.org X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: Microhertzing at LF: Content-Type: multipart/alternative; boundary=001517477fbcfb5df504abe8e3ba X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_20_30, HTML_FONTCOLOR_UNKNOWN,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 x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:510530368:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d280.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d40564e60096509f8 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --001517477fbcfb5df504abe8e3ba Content-Type: text/plain; charset=ISO-8859-1 Markus, Appreciate the test, your 100mW sure is QRO for this mode :-) How low can you go? Conditions earlier when you and Stefan transmitted in QRSS60 were at lest 10db worse than yesterday, there is also increased QRN as we expect some showers in the morning. Unfortunately I couldn't tune the YO window to your Tx frequency as it was a bit outside the FFT window, adjusted now. it will be interesting to see the result there and maybe better understand if the setup as it is today is usable for this slow mode. Hope Warren, Jay, John and maybe others will join in soon. Thanks for another interesting evening! 73s Chris On Fri, Sep 2, 2011 at 12:13 AM, Markus Vester wrote: > ** > > Hi Chris, > > thanks for this! The Saudi Loran traces (GRI 8830) look very accurate on > your 4X grabber. I will try to appear there tonight, and have started to > send a straight carrier on 137780.30. TX power is now reduced to about 100 > mW EMRP. > > Best 73, > Markus > > *From:* Chris 4X1RF > *Sent:* Thursday, September 01, 2011 1:34 PM > *To:* rsgb_lf_group@blacksheep.org > *Subject:* Re: Microhertzing at LF: > > Markus, LF, > > As a newcomer to LF I find this as an interesting experiment for real low > power or long distance tests for those who can achieve the necessary > frequency stability requirements. I found this to be quite a challenge... > > I have followed your initiative and started similar windows on my grabbers > in YO: http://dl.dropbox.com/u/10280270/YO/TA3600.jpg and 4X: > http://dl.dropbox.com/u/10280270/4X/TA3600.jpg > > The 4X grabber is currently using the Mercury HPSDR receiver ( > http://openhpsdr.org) which is GPSDO locked. However, the audio is routed > to SpectrumLab using Virtual Audio Cable as a virtual sound card. I have no > info regarding VAC sample rate accuracy or how I can automatically adjust it > so this may be a limiting factor, further experimentation is needed. In the > worst case, a real sound card could be used but then it also has to be > locked to GPS. > > The YO grabber is usually using GQD as a reference for the sound card > sample rate calibration in SpectrumLab and the LF receiver is based on a > laboratory grade VTCXO. GQD being off air, I was forced to use DHO which is > not very reliable during the night for me as can be seen on the 137.775 > Loran line. > > Thanks for the challenge! > > > 73s > Chris 4X1RF > > > > > > > On Wed, Aug 31, 2011 at 8:05 PM, Markus Vester wrote: > >> Dear LF, >> >> inspired by the very fruitful narrowband weak-signal detections on VLF, I >> have set up a temporary LF spectrogram, using Rubidium locked oscillators >> and a 0.438 mHz FFT bandwidth >> http://www.alice-dsl.net/df6nm/grabber/TAnarrow.jpg >> (updated every two hours). >> >> Frequency: >> The receive band is currently 7 Hz wide around 137777.5 Hz, within which >> the visible display slots can be shifted around a posteriori on request. At >> the moment I'm showing two slots around European Loran lines >> 137778.3705 Hz (GRI 7499 from Sylt and Lessay), >> 137775.0000 (GRI 8000 from Slonim and Simferopol). >> I chose the TA slot for the availability of other grabbers, but maybe a >> dedicated ultra-narrowband slot (eg. 10 MHz/73 = 136986.301 Hz) would be a >> better option - suggestions welcome! >> >> Sensitivity: >> Compared to my own 21 mHz TA grabber, the bandwidth reduction should >> provide a 17 dB reduction of noise, or 11 dB versus Argo-120 at 5.3 mHz. Of >> course you will need to transmit a much longer dash (eg. one hour instead of >> one minute) with good frequency stability. A GPS- or Rubidium-derived >> carrier would be the best option, but a good 1e-9 class OCXO would work just >> as well. >> >> Groundwave: >> In quiet daytime conditions, a radiated power of only 10 nanowatts should >> be able produce 10 dB SNR. This could be achieved by sending 5.5 mA up a >> whip at 1 m effective height! Or perhaps even from Lubos' ferrite antenna in >> TX mode? >> >> Skywave: >> During a few nights in Februrary 2006, John W1TAG transmitted GPS >> controlled straight and 15-minute phase-cycled carriers. Receptions in >> Europe by G3PLX and myself revealed long periods of stable skywaves, well >> suited for sub-millihertz analysis. Some details and spectrograms can be >> found in >> http://df6nm.bplaced.net/LF/slow_psk/ >> >> Now I hope to see some really feeble signals soon... >> >> Best 73, >> Markus (DF6NM) >> >> >> >> >> > > --001517477fbcfb5df504abe8e3ba Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Markus,

Appreciate the test, your 100mW sure is QRO= for this mode :-)=A0 How low can you go?

Conditions earlier when you and Stefan=A0 transmitted in QRSS60 were at lest 10db=20 worse than yesterday, there is also increased QRN as we expect some=20 showers in the morning.

Unfortunately I couldn't tune the YO window to your Tx frequency as= =20 it was a bit outside the FFT window, adjusted now. it will be=20 interesting to see the result there and maybe better understand if the=20 setup as it is today is usable for this slow mode.

Hope Warren, Jay, John and maybe others will join in soon.

Thank= s for another interesting evening!


73s
Chris

On Fri, Sep 2, 2011 at 12:13 AM, Markus Vester <markusvester@aol.com> wrote:
=A0
Hi Chris,
=A0
thanks for this! The Saudi Loran trace= s (GRI 8830)=20 look very accurate on your 4X grabber. I will try to appear there tonight, = and=20 have started=A0to send a straight carrier on 137780.30. TX power=A0is now= =20 reduced to about=A0100 mW EMRP.
=A0
Best 73,
Markus

Sent: Thursday, September 01, 2011 1:34 PM
Subject: Re: Microhertzing at LF:

Markus, LF,

As a newcomer to LF I find this as an= =20 interesting experiment for real low power or long distance tests for those = who=20 can achieve the necessary frequency stability requirements. I found this to= be=20 quite a challenge...

I have followed your initiative and started sim= ilar=20 windows on my grabbers in YO: http://dl.dropbox.com/u/10280270= /YO/TA3600.jpg=20 and 4X: http://dl.dropbox.com/u/10280270/4X/TA3600.jpg

The= =20 4X grabber is currently using the Mercury HPSDR receiver (http://openhpsdr.org) which is GPSDO = locked.=20 However, the audio is routed to SpectrumLab using Virtual Audio Cable as a= =20 virtual sound card. I have no info regarding VAC sample rate accuracy or ho= w I=20 can automatically adjust it so this may be a limiting factor, further=20 experimentation is needed. In the worst case, a real sound card could be us= ed=20 but then it also has to be locked to GPS.

The YO grabber is usually = using=20 GQD as a reference for the sound card sample rate calibration in SpectrumLa= b and=20 the LF receiver is based on a laboratory grade VTCXO. GQD being off air, I = was=20 forced to use DHO which is not very reliable during the night for me as can= be=20 seen on the 137.775 Loran line.

Thanks for the=20 challenge!


73s
Chris 4X1RF



=A0


On Wed, Aug 31, 2011 at 8:05 PM, Markus Vester <= span dir=3D"ltr"><markusvester@aol.com>=20 wrote:
Dear LF,
=A0
inspired by the very fruitful narrowband weak-signal detections on V= LF, I=20 have set up a temporary LF spectrogram, using Rubidium locked oscillators= and=20 a 0.438 mHz FFT bandwidth
=A0http://www.alice-dsl.net/df6nm/gr= abber/TAnarrow.jpg
(updated every two hours).
=A0
Frequency:
The receive band is currently 7 Hz wide around 137777.= 5 Hz,=20 within which the visible display slots can be shifted around a posteriori= on=20 request. At the moment I'm showing two slots around European Loran=20 lines
=A0137778.3705 Hz (GRI 7499 from Sylt and=20 Lessay),
=A0137775.0000 (GRI 8000 from Slonim and Simferopol).
I=20 chose the TA slot for the availability of other grabbers, but maybe a=20 dedicated ultra-narrowband slot (eg. 10 MHz/73 =3D 136986.301 Hz) would b= e a=20 better option - suggestions welcome!
=A0
Sensitivity:
Compared to my own 21 mHz TA grabber, the bandwidth= =20 reduction should provide a 17 dB reduction of noise, or 11 dB versus Argo= -120=20 at 5.3 mHz. Of course you will need to transmit a much longer dash (eg. o= ne=20 hour instead of one minute) with good frequency stability. A GPS- or=20 Rubidium-derived carrier would be the best option, but a good 1e-9 class = OCXO=20 would work just as well.
=A0
Groundwave:
In quiet daytime conditions, a radiated power of only= 10=20 nanowatts should be able produce 10 dB SNR. This could be achieved by sen= ding=20 5.5 mA up a whip at 1 m effective height! Or perhaps even from Lubos'= ferrite=20 antenna in TX mode?
=A0
Skywave:
During a few nights in Februrary 2006, John W1TAG transm= itted=20 GPS controlled straight and 15-minute phase-cycled carriers. Receptions i= n=20 Europe by G3PLX and myself revealed long periods of stable skywaves, well= =20 suited for sub-millihertz analysis. Some details and spectrograms can be = found=20 in
http://df6nm.bplaced.net/LF/slow_psk/
=A0
Now I hope to see some really feeble signals soon...
=A0
Best 73,
Markus (DF6NM)



=A0


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