Return-Path: Received: from mtain-de05.r1000.mx.aol.com (mtain-de05.r1000.mx.aol.com [172.29.64.205]) by air-dc01.mail.aol.com (v129.4) with ESMTP id MAILINDC011-85fd4caabed823a; Tue, 05 Oct 2010 01:59:52 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-de05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 5D94B3800009F; Tue, 5 Oct 2010 01:59:51 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1P30W4-0003un-2R for rs_out_1@blacksheep.org; Tue, 05 Oct 2010 06:56:44 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1P30W3-0003ue-CL for rsgb_lf_group@blacksheep.org; Tue, 05 Oct 2010 06:56:43 +0100 Received: from n2-vm0.bullet.mail.gq1.yahoo.com ([67.195.23.154]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1P30W1-0003n2-Ng for rsgb_lf_group@blacksheep.org; Tue, 05 Oct 2010 06:56:43 +0100 Received: from [67.195.9.81] by n2.bullet.mail.gq1.yahoo.com with NNFMP; 05 Oct 2010 05:56:34 -0000 Received: from [67.195.9.109] by t1.bullet.mail.gq1.yahoo.com with NNFMP; 05 Oct 2010 05:56:33 -0000 Received: from [127.0.0.1] by omp113.mail.gq1.yahoo.com with NNFMP; 05 Oct 2010 05:56:33 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 932864.35724.bm@omp113.mail.gq1.yahoo.com Received: (qmail 24805 invoked by uid 60001); 5 Oct 2010 05:56:33 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1286258193; bh=1A9vSNLj8fom98XeWRsu1tgI77EhmLqLDjPhV/Be3B0=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=4fZ7gAH3ywZ4TY2byk+swH4SoM8hFCanjt3mfGVhd+b3PdlaRWRbavugSg7Ya8ZUSmOtQk+GgBEYOujK4qBlouXWNg9fhR2UqNKpcXLX2rSVGPev8AESjL1u6gUcPuz+cmvyLQ9/YPHgRbHg/OCEu3n0hgIOHVEQuuPSqYxXn/Y= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=jUvgYT4Xr2Bqyy1C8s60h+eGgbAHBQq9RlU9inka1pkGwxbs6NG3XP4aBcQhXGFxo9FggzNMLdJIQY3ddkvfbarA/hmWRY05BeCLR/2zGLtF/YmZFE0i52tv+Mp3kSt9DVsjXqxkI9fBTvVxoNofN/Y9sQ74+7t5h113SrgZ1C4=; Message-ID: <781958.13947.qm@web111905.mail.gq1.yahoo.com> X-YMail-OSG: jiT7uN0VM1mgLAHzabPzJxV7OMdjq4GHo.6Oq8i7oSMgYYo trV3ercveCNE0ATcLHzFv2Z_xSkTRGjpTPBB6dVeLzWlW6jl0ryhravtAo_o 0Rg67RA5VCAyIwL9IIAdn4NTOCPrfy1zzFdrEWIp.AcWrYcWKV_LugsB2SN_ E8KMLfdtdLrXw37Xv7FADDC9d5A7XPqTVjXiZlEWOhWduNwAwrD44Z3xOfXf 2X8hqcAkG1jsSNNlx68d_rtl6r2GT4gcSrSinqVh3BhBQx_7c_ejavseStZd rtw-- Received: from [87.1.245.51] by web111905.mail.gq1.yahoo.com via HTTP; Mon, 04 Oct 2010 22:56:33 PDT X-Mailer: YahooMailRC/497 YahooMailWebService/0.8.105.279950 References: <4CA9BDE0.4000601@iup.uni-heidelberg.de> <646839.20132.qm@web111910.mail.gq1.yahoo.com> <4CAA4521.6070301@iup.uni-heidelberg.de> <455470.92877.qm@web111911.mail.gq1.yahoo.com> <4CAA611C.9050400@iup.uni-heidelberg.de> Date: Mon, 4 Oct 2010 22:56:33 -0700 (PDT) From: Daniele Tincani To: rsgb_lf_group@blacksheep.org In-Reply-To: <4CAA611C.9050400@iup.uni-heidelberg.de> MIME-Version: 1.0 DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: VLF: VLF at different locations and QRN as a function of daytime Content-Type: multipart/alternative; boundary="0-2011655598-1286258193=:13947" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=FORGED_YAHOO_RCVD,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-AUTHENTICATION: mail_rly_antispam_dkim-m231.2 ; domain : yahoo.com DKIM : pass x-aol-sid: 3039ac1d40cd4caabed62f33 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --0-2011655598-1286258193=:13947 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Hi Stefan, VLF, I agree with you. With 60 seconds/plot I think > 12 hours are possible on= my=20 screen (1280 pixels max horizontal size, 1024 used normally). Say 5.00 UTC= to=20 17.00 UTC for example. Please send me the .usr file to load. Currently my loop is=A0connected to a zero-impedance (ideally) pre-amplifi= er (a=20 design by Renato Romero IK1QFK and Marco Bruno IK1ODO, build around the LT= 1028A=20 op-amp). The cutoff frequency should be (in theory) fc =3D R/(2 x pi x L). If my me= asures=20 were not wrong some time ago, for my loop I should have R=3D3,7 ohms, C=3D= 186pF,=20 L=3D2,9mH which give an fc of about 203Hz (theoretically). The resonant fr= equency=20 should be > 200KHz, so I hope the response curve is fairly constant over= the VLF=20 range. A low-pass filter=A0with about 50KHz cut-off is included in the=20 pre-amplifier circuit. I'm planning to add some shielding to the loop by means of metal tape to= see if=20 I can get an improved balancing and better rejection of common-mode noise= (quite=20 a quick and unexpensive attempt). I also thought=A0about adding a switchab= le=20 passive high-pass filter with say 5KHz cut-off before the amplifier, but= an=20 analysis of my signal made by Renato months ago showed that there wasn't= any=20 input saturation at low frequencies, so a filter will probably help poorly= in=20 reducing local noise in the dreamer's band. Anyway, I will try and see wha= t=20 happens :-) Regards Daniele ________________________________ From: Stefan Sch=E4fer To: rsgb_lf_group@blacksheep.org Sent: Tue, October 5, 2010 1:19:56 AM Subject: Re: VLF: VLF at different locations and QRN as a function of dayt= ime Hello Daniele, VLF, Yes, sharing the same usr file could be useful. My grabber is currently co= vering=20 about 13 hours in the wideband window but 24 hours makes sense i think. Th= e=20 sampling rate should be 48 kS/s since most amateurs have no 'special' and= =20 expensive soundcards.=20 If you want i will arrange a suitable usr file? But the time that is cover= ed is=20 a function of the size of your monitor so we should define the capture siz= e in=20 pixels. I am using 980 pixels on my grabber... The next question is the frequency response of differnet RX antennas (due= to the=20 design). If the lower cut off frequency is above 6 kHz, it might be diffic= ult t=20 compare. Maybe it is best you and others who want to take part of this ide= a,=20 just show a capture from 0...24 kHz and some hours (> 10) to get a first= =20 impression? 73, Stefan Am 04.10.2010 23:56, schrieb Daniele Tincani:=20 Hello Stefan, VLF, > >would a wide-band capture over 24 hours from my QTH/receiver be of some= interest=20 >for you? If so, I think I could be able to send=A0the results to you by= the end of=20 >this week or so (hoping batteries last enough :-)).=A0Probably it could= make sense=20 >to share the same .usr file for SpecLab so that to ensure a bit of consis= tency=20 >when comparing figures from different locations. >My sound card support 96KHz sampling at 24 bits/sample, but I found that= card's=20 >noise looks much better when sampling at 48KHz. > >Best regards >Daniele > > > > ________________________________ From: Stefan Sch=E4fer >To: rsgb_lf_group@blacksheep.org >Sent: Mon, October 4, 2010 11:20:33 PM >Subject: Re: VLF: VLF at different locations and QRN as a function of day= time > >Hi Daniele, > >No problem about the callsign ;-) On VLF you don't even need one for=20 >transmitting, hi. > >Oh, you are in JN53EM, i haven't known that. The distance is 707 km! This= is the=20 >3rd best distance at all! Unbelivable, for a antenna in that location, ve= ry=20 >fine!!! > >I hope cou can improve your RX situation if this is your goal. > >And i hope i can transmit more meaningful messages the next time ;-) > >73, Stefan/DK7FC > >Am 04.10.2010 14:57, schrieb Daniele Tincani:=20 >Hello Stefan, VLF, >> >>frankly speaking, it is still unbelievable to me that I was able to=A0ca= tch a=20 >>faint trace of your signal and see it appearing on my PC. This is becaus= e of the=20 >>intense hum at my location and the unsophisticated reception system that= I use.=20 >>Anyway, I'm=A0glad to=A0read your opinion that the screenshot I captured= was really=20 >>showing your tx :-) >>I'm also interested in supporting your idea of collecting information ab= out=20 >>local QRN at different locations. I'm aways looking for simple-to-build= =20 >>solutions for improving my setup. May be some helpful information could= emerge=20 >>from this data analysis you are proposing. >>For the time being, these are the information you have requested: the lo= cator is=20 >>JN53EM. As for the callsign, I'm sorry, I haven't one. I'm only "registe= red" as=20 >>a SWL and my identifier is I0169LI (http://www.qrz.com/db/I0169LI/). >> >>Cheers >>Daniele >> >> > =20 --0-2011655598-1286258193=:13947 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Hi Stefan, VLF,
 
I agree with you. With 60 seconds/plot I think > 12 hours are poss= ible on my screen (1280 pixels max horizontal size, 1024 used normally).= Say 5.00 UTC to 17.00 UTC for example. Please send me the .usr file to lo= ad.
 
Currently my loop is connected to a zero-impedance (ideally) pre= -amplifier (a design by Renato Romero IK1QFK and Marco Bruno IK1ODO, build= around the LT1028A op-amp).
The cutoff frequency should be (in theory) fc =3D R/(2 x pi x L). If= my measures were not wrong some time ago, for my loop I should have R=3D3= ,7 ohms, C=3D186pF, L=3D2,9mH which give an fc of about 203Hz (theoretical= ly). The resonant frequency should be > 200KHz, so I hope the response= curve is fairly constant over the VLF range. A low-pass filter with= about 50KHz cut-off is included in the pre-amplifier circuit.
 
I'm planning to add some shielding to the loop by means of metal tape= to see if I can get an improved balancing and better rejection of common-= mode noise (quite a quick and unexpensive attempt). I also thought ab= out adding a switchable passive high-pass filter with say 5KHz cut-off bef= ore the amplifier, but an analysis of my signal made by Renato months ago= showed that there wasn't any input saturation at low frequencies, so a fi= lter will probably help poorly in reducing local noise in the dreamer's ba= nd. Anyway, I will try and see what happens :-)
 
Regards
Daniele
=
From: Stefan Sch=E4fer <= ;schaefer@iup.uni-heidelberg.de>
Sent: Tue, October 5, 2010 1:19:56 AM
Subject: Re: VLF: VLF at different= locations and QRN as a function of daytime

Hello Daniele,= VLF,

Yes, sharing the same usr file could be useful. My grabber is= currently covering about 13 hours in the wideband window but 24 hours mak= es sense i think. The sampling rate should be 48 kS/s since most amateurs= have no 'special' and expensive soundcards.

If you want i will ar= range a suitable usr file? But the time that is covered is a function of= the size of your monitor so we should define the capture size in pixels.= I am using 980 pixels on my grabber...

The next question is the fr= equency response of differnet RX antennas (due to the design). If the lower cut off frequency= is above 6 kHz, it might be difficult t compare. Maybe it is best you and= others who want to take part of this idea, just show a capture from 0...2= 4 kHz and some hours (> 10) to get a first impression?

73, Stefa= n

Am 04.10.2010 23:56, schrieb Daniele Tincani:=20
Hello Stefan, VLF,
 
would a wide-band capture over 24 hours from my QTH/receiver be of so= me interest for you? If so, I think I could be able to send the resul= ts to you by the end of this week or so (hoping batteries last enough :-))= . Probably it could make sense to share the same .usr file for SpecLa= b so that to ensure a bit of consistency when comparing figures from diffe= rent locations.
My sound card support 96KHz sampling at 24 bits/sample, but I found= that card's noise looks much better when sampling at 48KHz.
 
Best regards
Daniele
=
From: Stefan Sch=E4fer <schaefer@iup.uni-heidelberg.de>
To: rsgb_lf_group@blacksheep.= org
Sent: Mon, Octo= ber 4, 2010 11:20:33 PM
Subject: Re: VLF: VLF at different locations and QRN as a function of day= time

Hi Daniele,

No problem about the callsign ;-) On= VLF you don't even need one for transmitting, hi.

Oh, you are in= JN53EM, i haven't known that. The distance is 707 km! This is the 3rd bes= t distance at all! Unbelivable, for a antenna in that location, very fine!!!

I hope cou can improve your= RX situation if this is your goal.

And i hope i can transmit more= meaningful messages the next time ;-)

73, Stefan/DK7FC

Am= 04.10.2010 14:57, schrieb Daniele Tincani:=20
Hello Stefan, VLF,
 
frankly speaking, it is still unbelievable to me that I was able to&n= bsp;catch a faint trace of your signal and see it appearing on my PC. This= is because of the intense hum at my location and the unsophisticated rece= ption system that I use. Anyway, I'm glad to read your opinion= that the screenshot I captured was really showing your tx :-)
I'm also= interested in supporting your idea of collecting information about local= QRN at different locations. I'm aways looking for simple-to-build solutio= ns for improving my setup. May be some helpful information could emerge fr= om this data analysis you are proposing.
For the time being, these are the information you have requested: the= locator is JN53EM. As for the callsign, I'm sorry, I haven't one. I'm onl= y "registered" as a SWL and my identifier is I0169LI (http://www.qrz.com/d= b/I0169LI/).
 
Cheers
Daniele




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