Return-Path: X-Spam-DCC: paranoid 1233; 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=-1.9 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_40_50,HTML_MESSAGE autolearn=no 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 tAKMQwmY011359 for ; Fri, 20 Nov 2015 23:26:58 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Zzu5W-0001iw-He for rs_out_1@blacksheep.org; Fri, 20 Nov 2015 22:23:26 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Zzu5W-0001in-6w for rsgb_lf_group@blacksheep.org; Fri, 20 Nov 2015 22:23:26 +0000 Received: from omr-a017e.mx.aol.com ([204.29.186.68]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.86) (envelope-from ) id 1Zzu4W-0005XM-NX for rsgb_lf_group@blacksheep.org; Fri, 20 Nov 2015 22:23:25 +0000 Received: from mtaout-mad01.mx.aol.com (mtaout-mad01.mx.aol.com [172.26.221.205]) by omr-a017e.mx.aol.com (Outbound Mail Relay) with ESMTP id DBE1638000A1 for ; Fri, 20 Nov 2015 17:22:08 -0500 (EST) Received: from White (ipbcc05f3c.dynamic.kabel-deutschland.de [188.192.95.60]) by mtaout-mad01.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id 0716A38000086 for ; Fri, 20 Nov 2015 17:22:05 -0500 (EST) Message-ID: From: "Markus Vester" To: References: <564E4046.9030602@gmail.com> <8D2F12F1F72FA45-156C-ECE7D@webmail-vm019.sysops.aol.com> <564F0A31.30604@abelian.org> Date: Fri, 20 Nov 2015 23:22:01 +0100 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=20150623; t=1448058128; bh=qFHH4Oi6F2uWK2VmHXC38aUyVWkTSuOgv4ZWKoWhXWU=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=DBOMUEjzmWkdAPjCFZwnUNBrGEu/mdWc0D/l39rD5oQ4rMNOOazkp0WXr95k6dYY2 vD6EIdJgrPWxFJiiFZi9hhvuctNRKsQeHA9LxFZOkn0w71SaqUDw/am1F9BPZ6cXKf ksDXuLTggdrDkv2JoOMMQyDygmLX8OPMd+un2+MU= x-aol-sid: 3039ac1addcd564f9d0d5937 X-AOL-IP: 188.192.95.60 X-Scan-Signature: 3dad7246509e3b317974c9d84e795ac1 Subject: Re: LF: EbNaut LF test from iz7slz Content-Type: multipart/alternative; boundary="----=_NextPart_000_000D_01D123EA.42DF60B0" 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: O X-Status: X-Keywords: X-UID: 5232 Dies ist eine mehrteilige Nachricht im MIME-Format. ------=_NextPart_000_000D_01D123EA.42DF60B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Paul, looking at your spectrograms three weeks ago, your direct-sampling LF = receiver actually seemed to be doing rather well! It's surely sensitive = enough, and apparently not limited by ADC noise or dynamic range. I = think that the initial lack of IZ7SLZ daytime decodes is not showing a = receiver deficit but only due to sheer distance between the two of you.=20 GPS injection into the antenna signal doesn't have to be bad either. I = have often used a cheap mono sound dongle for VLF, and SpecLab with 1pps = lock and absolute-phase NCO produced clean traces down to 46 uHz FFT, = even riding through multiple soundcard dropouts. The 1 Hz harmonics from = the 1pps were completely cleared by the noiseblanker. One big advantage = with direct RF sampling is that you don't have to worry about the local = oscillator as another source of potential frequency and phase = uncertainty. Best 73, Markus From: Paul Nicholson=20 Sent: Friday, November 20, 2015 12:55 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: EbNaut LF test from iz7slz Domenico wrote: > transmission in progress (21:30 UT) is formed > by 39 characters at 0.5s. Sorry I was unable to decode this one. Tried list 100k with time offsets -0.1 to +0.9 in 0.02 second steps. My receiving system is not very good. You guys are doing much better because you have proper receivers. Here I am trying to use the same method that I use on VLF: direct reception through a soundcard, and it is just not working out very well. The only soundcard I have which will clock fast enough has a mono input which means I have to mix the PPS and LF together into the one input. That, and the card itself being quite noisy, makes it difficult to apply a precise time stamp to the signal samples. It is working, just not well enough and it looks like I'm losing a dB or two at least. It means I can't make accurate measurements of carrier phase and although we're getting some success with EbNaut messages, we cannot tell yet whether the band will support long distance long duration coherent signalling when the received signal is too weak to extract a reference phase. Hopefully someone better equipped will be able to measure the phase variations of a long T/A carrier. -- Paul Nicholson -- ------=_NextPart_000_000D_01D123EA.42DF60B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Paul,
 
looking at your spectrograms three = weeks ago,=20 your direct-sampling LF receiver actually seemed to be doing rather = well!=20 It's surely sensitive enough, and apparently not limited by ADC noise or = dynamic=20 range. I think that the initial lack of IZ7SLZ daytime decodes = is not=20 showing a receiver deficit but only due to sheer distance between = the two=20 of you.
 
GPS injection into the antenna signal = doesn't have=20 to be bad either. I have often used a cheap mono sound = dongle for=20 VLF, and SpecLab with 1pps lock and absolute-phase NCO = produced clean=20 traces down to 46 uHz FFT, even riding through multiple = soundcard=20 dropouts. The 1 Hz harmonics from the 1pps were completely cleared = by the=20 noiseblanker. One big advantage = with direct RF=20 sampling is that you don't have to worry about the local oscillator = as=20 another source of potential frequency and phase = uncertainty.
 
Best 73,
Markus
 
 

From: Paul Nicholson
Sent: Friday, November 20, 2015 12:55 PM
Subject: Re: LF: EbNaut LF test from = iz7slz


Domenico wrote:
 > transmission in = progress (21:30=20 UT) is formed
 > by 39 characters at 0.5s.

Sorry I was = unable=20 to decode this one.  Tried list 100k
with time offsets -0.1 to = +0.9 in=20 0.02 second steps.

My receiving system is not very good.  = You guys=20 are doing much
better because you have proper receivers.  Here I = am=20 trying
to use the same method that I use on VLF: direct = reception
through=20 a soundcard, and it is just not working out very well.

The only = soundcard=20 I have which will clock fast enough has a
mono input which means I = have to=20 mix the PPS and LF together
into the one input.  That, and the = card=20 itself being quite
noisy,  makes it difficult to apply a precise = time=20 stamp to
the signal samples.   It is working, just not well = enough=20 and
it looks like I'm losing a dB or two at least.

It means I = can't=20 make accurate measurements of carrier phase
and although we're = getting some=20 success with EbNaut messages,
we cannot tell yet whether the band = will=20 support long distance
long duration coherent signalling when the = received=20 signal is
too weak to extract a reference phase.

Hopefully = someone=20 better equipped will be able to measure the
phase variations of a = long T/A=20 carrier.

--
Paul Nicholson
--

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