Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dd03.r1000.mx.aol.com (Internet Inbound) with ESMTP id 4DD4938000092; Mon, 30 Jan 2012 17:08:40 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1RrzNw-0005tx-Sh for rs_out_1@blacksheep.org; Mon, 30 Jan 2012 22:07:36 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1RrzNw-0005to-5R for rsgb_lf_group@blacksheep.org; Mon, 30 Jan 2012 22:07:36 +0000 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1RrzNv-0001h1-Ht for rsgb_lf_group@blacksheep.org; Mon, 30 Jan 2012 22:07:36 +0000 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id q0UM7XRW025534 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 30 Jan 2012 23:07:34 +0100 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id q0UM7Xer005089; Mon, 30 Jan 2012 23:07:33 +0100 Message-ID: <4F27148A.2010101@iup.uni-heidelberg.de> Date: Mon, 30 Jan 2012 23:07:06 +0100 From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org CC: Paul References: <4F246297.4020304@charter.net> <50DDDC5E26754BC284D529DCB4A1C2C3@White> <4F258CB5.2090105@charter.net> <4F25DA96.3080607@iup.uni-heidelberg.de> <4F25F3D0.70503@iup.uni-heidelberg.de> <4F26E06D.2000507@iup.uni-heidelberg.de> <4F26E836.4010106@iup.uni-heidelberg.de> In-Reply-To: X-Spam-Score: 2.4 (++) X-Spam-Report: autolearn=disabled,HTML_10_20=0.945,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: VLF: WOLF, next step.. Content-Type: multipart/alternative; boundary="------------050102020705010106030203" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=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: 0:2:374234848:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d408f4f2714e867d7 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------050102020705010106030203 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id q0UM7XRW025534 Bill, VLF, A first test on 8970 Hz, audio propagation between my office PC and my=20 /p netbook was successful in the first attempt, without any calibrating=20 of a soundcard: 2012-01-30 21:54:33 >WOLF10 -r 24000 -f 8970 -t 1.0 -w 0.0000 -ut 21:54:57 f:-0.245 a: 1.4 dp: 19.3 ci:15 cj:254 ??????948???/CF ? 21:55:21 f:-0.244 a: 1.3 dp: 22.0 ci:15 cj:254 DK7FC JN49IK00 - 21:56:09 f:-0.243 a: 1.2 dp: 16.5 ci:15 cj:254 DK7FC JN49IK00 - ...Now i'll aply this signal to the PA. Maybe i actually will use the DDS (drifting some mHz) and a CD4070 XOR=20 gate to toggle the phase. Then, i prevent phase glitches coming from the=20 soundcard. If all works well i will start a first test on 8970 Hz using my fixed=20 antenna *tonite* or tomorrow. 1 km distance should be no problem at all.=20 Maybe its time to ask local VLF receiving stations (DD7PC, Michael=20 Oexner, ...) for a receive test. If i can manage to get some kV out of the LOPT then i could arrange a=20 VLF beacon running 24/7 (even during wind and rain). *Is there someone in EU/UK interested in a WOLF DX test from=20 Heidelberg?* In contrast to LF it is very interesting for me since a=20 real message can be transmitted, regardless how long it takes. One has=20 just to wait until something appears ;-) 73, Stefan/DK7FC Am 30.01.2012 22:33, schrieb Bill de Carle: > Stefan: > I wouldn't change the phase reversal time - if you announce to the=20 > world you're transmitting WOLF-10 that means phase transitions can=20 > occur only at exact multiples of 100 milliseconds - everyone's=20 > receiver will make that assumption. Don't worry about sync-ing phase=20 > shifts to the zero crossings of the audio waveform, let's see if your=20 > computer-to-computer test works first. You can specify a relaxed=20 > tolerance for the receiver: e.g. +/- 2 Hz away from the nominal=20 > carrier frequency to allow for slightly different sample rates at Tx,=20 > Rx. Ultimately for long term coherent integration both Tx and Rx must=20 > agree on the timing but for a first test with a strong signal (just to=20 > see if everything is working), you won't need that. For longer=20 > integration times it is probably better to use a GPS-stabilized DDS to=20 > directly generate the WOLF signal at the Tx end. I find sound card=20 > sampling rates are stable enough for WOLF once everything has warmed=20 > up a bit. It's not the small instabilities that will hurt, it's that=20 > the absolute sample rate must be known accurately and entered to allow=20 > the Rx clock to keep same time as the Tx clock. Did you download that=20 > .wav file I made last night? I intended that only for testing your Tx=20 > to see what the sidebands look like with no waveform envelope=20 > shaping. Don't expect anyone else to copy that message unless your=20 > sample rate is very close to 24000 s/s and the signal strength at the=20 > Rx is high enough to enable decoding within seconds, not minutes or=20 > hours. > Good luck! > 73, > Bill VE2IQ > > At 01:57 PM 1/30/2012, Stefan DK7FC wrote: >> Bill, >> >> Thought about the zero-crosings. Does it actually make sense to=20 >> change the phase reversal time? Since the samplerate is drifting=20 >> anyway, there will be a small time difference between a phase shift=20 >> and there zero-crossing. Also -if the samplerate would be exactly 24=20 >> kS/s-, the time when the phase shift occurrs can be somewhere, i.e.=20 >> wouldn't be sync'ed to the zero-crossing. Right? >> So it may be easier (also for the receiving side) to let it remain at=20 >> 0.1 seconds. >> Comments welcome. >> >> 73, Stefan/DK7FC >> >> >> Am 30.01.2012 19:24, schrieb Stefan Sch=E4fer: >>> Changed the phase reversal time from 0.1 s to 0.111482720178372 s=20 >>> (=3D1000/8970Hz) Seems to work. >> >> >> Am 30.01.2012 01:37, schrieb Bill de Carle: >>> Can your Tx handle abrupt phase shifts every 100 msec? We can=20 >>> arrange for the phase shifts to occur only at zero-crossings of the=20 >>> 8970-Hz sinewave. > > --------------050102020705010106030203 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Bill, VLF,

A first test on 8970 Hz, audio propagation between my office PC and my /p netbook was successful in the first attempt, without any calibrating of a soundcard:

2012-01-30 21:54:33 >WOLF10  -r 24000 -f 8970 -t 1.0 -w 0.0000 -ut
21:54:57 f:-0.245 a: 1.4 dp: 19.3 ci:15 cj:254 ??????948???/CF ?
21:55:21 f:-0.244 a: 1.3 dp: 22.0 ci:15 cj:254 DK7FC JN49IK00  -
21:56:09 f:-0.243 a: 1.2 dp: 16.5 ci:15 cj:254 DK7FC JN49IK00  -


...Now i'll aply this signal to the PA.
Maybe i actually will use the DDS (drifting some mHz) and a CD4070 XOR gate to toggle the phase. Then, i prevent phase glitches coming from the soundcard.

If all works well i will start a first test on 8970 Hz using my fixed antenna tonite or tomorrow. 1 km distance should be no problem at all. Maybe its time to ask local VLF receiving stations (DD7PC, Michael Oexner, ...) for a receive test.
If i can manage to get some kV out of the LOPT then i could arrange a VLF beacon running 24/7 (even during wind and rain).

Is there someone in EU/UK interested in a WOLF DX test from Heidelberg? In contrast to LF it is very interesting for me since a real message can be transmitted, regardless how long it takes. One has just to wait until something appears ;-)

73, Stefan/DK7FC


Am 30.01.2012 22:33, schrieb Bill de Carle:
Stefan:
I wouldn't change the phase reversal time - if you announce to the world you're transmitting WOLF-10 that means phase transitions can occur only at exact multiples of 100 milliseconds - everyone's receiver will make that assumption.  Don't worry about sync-ing phase shifts to the zero crossings of the audio waveform, let's see if your computer-to-computer test works first.  You can specify a relaxed tolerance for the receiver: e.g. +/- 2 Hz away from the nominal carrier frequency to allow for slightly different sample rates at Tx, Rx.  Ultimately for long term coherent integration both Tx and Rx must agree on the timing but for a first test with a strong signal (just to see if everything is working), you won't need that.  For longer integration times it is probably better to use a GPS-stabilized DDS to directly generate the WOLF signal at the Tx end.  I find sound card sampling rates are stable enough for WOLF once everything has warmed up a bit.  It's not the small instabilities that will hurt, it's that the absolute sample rate must be known accurately and entered to allow the Rx clock to keep same time as the Tx clock.  Did you download that .wav file I made last night?  I intended that only for testing your Tx to see what the sidebands look like with no waveform envelope shaping.  Don't expect anyone else to copy that message unless your sample rate is very close to 24000 s/s and the signal strength at the Rx is high enough to enable decoding within seconds, not minutes or hours.
Good luck!
73,
Bill VE2IQ

At 01:57 PM 1/30/2012, Stefan DK7FC wrote:
Bill,

Thought about the zero-crosings. Does it actually make sense to change the phase reversal time? Since the samplerate is drifting anyway, there will be a small time difference between a phase shift and there zero-crossing. Also -if the samplerate would be exactly 24 kS/s-, the time when the phase shift occurrs can be somewhere, i.e. wouldn't be sync'ed to the zero-crossing. Right?
So it may be easier (also for the receiving side) to let it remain at 0.1 seconds.
Comments welcome.

73, Stefan/DK7FC


Am 30.01.2012 19:24, schrieb Stefan Schäfer:
Changed the phase reversal time from 0.1 s to 0.111482720178372 s (=1000/8970Hz) Seems to work.


Am 30.01.2012 01:37, schrieb Bill de Carle:
Can your Tx handle abrupt phase shifts every 100 msec?  We can arrange for the phase shifts to occur only at zero-crossings of the 8970-Hz sinewave.


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