Delivered-To: daveyxm@virginmedia.com Received: by 10.50.237.98 with SMTP id vb2csp379785igc; Thu, 23 Jan 2014 06:01:54 -0800 (PST) X-Received: by 10.194.185.205 with SMTP id fe13mr6809114wjc.23.1390485713983; Thu, 23 Jan 2014 06:01:53 -0800 (PST) Return-Path: Received: from post.thorcom.com (post.thorcom.com. [195.171.43.25]) by mx.google.com with ESMTP id dz6si9253467wib.32.2014.01.23.06.01.53 for ; Thu, 23 Jan 2014 06:01:53 -0800 (PST) Received-SPF: neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) client-ip=195.171.43.25; Authentication-Results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) smtp.mail=owner-rsgb_lf_group@blacksheep.org; dkim=pass header.i=@kabelmail.de Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1W6Jqw-0008Dl-EQ for rs_out_1@blacksheep.org; Thu, 23 Jan 2014 12:57:50 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1W6Jqv-0008Dc-Mc for rsgb_lf_group@blacksheep.org; Thu, 23 Jan 2014 12:57:49 +0000 Received: from smtpa1.mediabeam.com ([194.25.41.13] helo=smtpa2.mediabeam.com) by relay1.thorcom.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.77) (envelope-from ) id 1W6Jqs-0001By-MQ for rsgb_lf_group@blacksheep.org; Thu, 23 Jan 2014 12:57:48 +0000 Received: from IMAP1 (balancer7.mediabeam.com [10.100.1.80]) by smtpa2.mediabeam.com (8.13.8/8.13.1) with ESMTP id s0NCvjRJ022828 for ; Thu, 23 Jan 2014 13:57:45 +0100 X-DKIM-Result: Domain=kabelmail.de Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kabelmail.de; s=mail; t=1390481865; bh=h0cCczITFePFm4epyVK1Jr87q1D3EbfvjkcgoRz8o/Q=; h=Date:From:To:Subject; b=Wq/GgOV05UnZWTOGpuVRGiIfL0YCGqm/Ry+ZZ88KL9nj2tS1o6XAAtOI53j2048S6 EvO96o17KR9/r1nEGONdGNADIO+gdMqOSSIAWozvLIb7OYbx6c0Zw3mgc2h2LJESjj CDXaeQgHyntvBCW5ulgehmEQbLERHsqVjC7FB8S8= Date: Thu, 23 Jan 2014 13:57:43 +0100 From: uwe-jannsen@kabelmail.de To: rsgb_lf_group@blacksheep.org Message-ID: X-Priority: 3 (Normal) MIME-Version: 1.0 X-Spam-Score: -0.7 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hi Markus, now since 1238utc ZOA in 1pps_PLL.usr mode on 8270.004Hz we will see GL Uwe Von: rsgb_lf_group@blacksheep.org Gesendet: 23.01.2014 00:24 An: rsgb_lf_group@blacksheep.org Kopie: Paul@abelian.netcom.co.uk Betreff: VLF: Transmit phase correction [...] Content analysis details: (-0.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [194.25.41.13 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: ea563abf4a6f6bcc595ed299b802c617 Subject: Re: VLF: Transmit phase correction Content-Type: multipart/alternative; boundary="----75BB84ADB15A487F8345488BE2C30567" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.9 required=5.0 tests=HTML_30_40,HTML_MESSAGE, NO_REAL_NAME,PRIORITY_NO_NAME 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 ------75BB84ADB15A487F8345488BE2C30567 Content-type: text/plain; charset=Windows-1252 Content-Transfer-Encoding: quoted-printable Hi Markus, now since 1238utc ZOA in 1pps_PLL=2Eusr mode on 8270=2E004Hz we will see GL Uwe Von: rsgb_lf_group@blacksheep=2Eorg Gesendet: 23=2E01=2E2014 00:24 An: rsgb_lf_group@blacksheep=2Eorg Kopie: Paul@abelian=2Enetcom=2Eco=2Euk Betreff: VLF: Transmit phase correction Hi Wolf, Uwe, Peter,=20 after a little experimentation, I think I have found a way to set up Sp= ecLab to=A0eliminate transmit phase=A0jumps caused by dropouts in the s= oundcard=A0output=2E=A0As a proof of concept,=A0I=A0generated an=A08269= =2E998 Hz audio=A0carrier=A0last night=2E This happened to=A0leak=A0fro= m the audio wires=A0to my VLF antenna, and produced a weak but well def= ined dash in the 42 uHz grabber window=2E=20 We can use SpecLabs GPS=A0tracking to take care of any irregularities i= n the sound input path to the ADC=2E When using the 1-pps reference wit= h=A0phaselock it can identify and correct short dropouts=2E Augmented b= y the built-in NMEA-based timestamping scheme, SpecLab can=A0in princip= le=A0even=A0provide a defined=A0absolute phase, referenced to the begin= ning of the UT day=2E =20 But the timing is always relative to the reference seen by the ADC inpu= t, and there is no way to directly sense latency variations in the buff= ering between the software=A0and the DAC output=2E Unfortunately on man= y machines,=A0buffer underflows or dropouts on the playback side seem t= o happen fairly often, especially when the PC is not left alone but is = used for other jobs on the side=2E=20 The idea is to feed back a sample of the analog output to the input, us= ing either an analog loopback (eg the audio mixer, but not a digital lo= op like VAC)=2E Or set up a pickup probe to sense antenna current or vo= ltage, which would also take care of=A0phase shifts from variable anten= na tuning=2E Then SpecLab can do a phase comparison to a=A0GPS-referenc= ed=A0internal generator, and steer the=A0frequency of an independent ou= tput oscillator to=A0bring the radiated signal=A0back to the correct ph= ase=2E=20 If you want to experiment with this method, you can download=A0the conf= iguration file =20 http://dl=2Edropboxusercontent=2Ecom/u/26404526/VLF_TX_1pps_PLL=2EUSR=A0= =20 which generates a 8270 Hz stabilised signal=2E To see how it works, tak= e a look at the circuit diagram in:=20 http://dl=2Edropboxusercontent=2Ecom/u/26404526/screenshot_VLF_TX_1pps_= PLL=2Ejpg=20 The output signal is generated by the digimode terminal block, which ca= n be set up either for a continuous carrier, or for QRSS or Opera modul= ation if you want=2E It feeds the DAC and the power amplifier through L= 5=2E The output is brought back to the left input=A0(L1) and fed to the= "E" channel of=A0a colour-DF spectrogram=2E The right channel (R1) get= s the 1pps signal from the GPS=A0which is used=A0for=A0samplerate lock=2E= Lacking an appropriate GPS unit, I'm not using NMEA timestamps here, b= ut you could chose so if your unit provides serial data=A0with proper t= iming=2E=20 The=A0steady reference frequency is provided by the test signal generat= or -=A0this is where you enter your desired output frequency=2E It is f= ed to the second "H" channel of the spectrogram through R5=2E The colou= r (azimuth) of the trace=A0gives an indication of the phase difference = between L1 and R5=2E=20 The phase lock is implemented as a=A0macro in conditional actions: Ever= y 200 ms, it checks whether there is a valid probe signal at L1, and is= so, it=A0shifts=A0the digimode frequency within +-0=2E18 Hz according = to the phase difference=2E Check this by turmning the DAC=A0off and on:= =A0The trace comes back on with an arbitrary colour, but =A0it will alw= ays revert to green (180=B0) within about three seconds=2E=A0=20 So to get started,=20 -=A0set up the analog loop path and the 1-pps,=A0=20 - load VLF_TX_1pps_PLL=2Eusr,=20 - change the=A0test signal generator=A0frequency from Uwe's 8270=2E004 = to yours, =20 -=A0set the digimode teminal to send unmodulated test tone at TX freque= ncy=2E=20 - enjoy!=20 Hope this may be useful=2E=20 Best 73,=20 Markus (DF6NM)=20 From: wolf_dl4yhf =20 Sent: Sunday, January 19, 2014 7:01 PM=20 To: Markus Vester =20 Cc: Paul ; Uwe Jannsen =20 Subject: Re: DJ8WX 8270=2E004 Hz - transmit phase correction? =20 Hello Markus and all, Am 19=2E01=2E2014 18:43, schrieb Markus Vester: 30 dB =2E=2E=2Enot too bad, is it?=20 Still wondering about the nature of those transmit glitches=2E Assuming= perfect GPS sync,=A0all=A0possible interruptions in the input data str= eam could be detected by the timestamp identification=2E But=A0there=A0= is still a chance for undetected=A0buffer underruns in the sound output= =2E=A0Would that affect the phase permanently?=A0Or would the average f= ill state of the FIFO buffering=A0eventually=A0be pulled back to the or= iginal lag (probably not)?=2E=20 I have been pondering a scheme where one audio channel is getting 1pps = while the other is used to=A0sample=A0the transmitter output, eg with a= small pickup loop=2E That way all phase variations in the transmit cha= in would be caught, and the=A0software oscillator could be steered to r= evert to the original phase within a few seconds=2E With timestamping,=A0= we could even prescribe=A0absolute phase, allowing comparative measurem= ents=A0across different sessions=A0many days apart=2E=20 Wolf what do you think? If it makes sense, I might try to implement=A0s= omething=A0based on the Sndinput / Sndoutpt=A0combo=2E=A0 Yes, certainl= y=2E If there was a drop-out of the audio output, we cannot be sure if = the latency between 'application' and the arrival of the sample at the = D/A-converter remains exactly the same=2E Observing the phase of the *r= adiated signal* and steering the signal generated by software to get th= e phase 'back where it belongs' would be better because it would also c= ompensate phase deviations caused by the antenna itself=2E Have a nice evening, =A0 Wolf =2E Best 73,=20 Markus ------75BB84ADB15A487F8345488BE2C30567 Content-type: text/html; charset=Windows-1252 Content-Transfer-Encoding: quoted-printable
Hi Markus,
now since 1238utc ZOA in 1pps_PLL=2Eusr mode on 8270=2E004Hz
we will see
GL
Uwe
Von: rsgb_lf_group@blacksheep=2Eorg
Gesendet: 23=2E01=2E2014 00:24
An: rsgb_lf_group@blacksheep=2Eorg
Kopie: Paul@abelian=2Enetcom=2Eco=2Euk
Betreff: VLF: Transmit phase correction

Hi Wolf, Uwe,= Peter,
 =
after a littl= e experimentation, I think I have found a way to set up SpecLab to eliminate transmit phase jum= ps caused by dropouts in the soundcard output=2E As a proof of concept, I generated an 8269=2E998 Hz audio carrier last night=2E This happen= ed to leak from the audio wires to my VLF antenna, and prod= uced a weak but well defined dash in the 42 uHz grabber window=2E
 =
We can use Sp= ecLabs GPS tracking to take care of any irregularities in the sound input path to the ADC=2E When using = the 1-pps reference with phaselock it can identify and correct short dropout= s=2E Augmented by the built-in NMEA-based timestamping scheme, SpecLab can&n= bsp;in principle even provide a defined absolute phase, referen= ced to the beginning of the UT day=2E
 =
But the timin= g is always relative to the reference seen by the ADC input, and there is no way to directly sense latency va= riations in the buffering between the software and the DAC output=2E Unfort= unately on many machines, buffer underflows or dropouts on the playback side = seem to happen fairly often, especially when the PC is not left alone but is us= ed for other jobs on the side=2E
 =
The idea is t= o feed back a sample of the analog output to the input, using either an analog loopback (eg the audio mixe= r, but not a digital loop like VAC)=2E Or set up a pickup probe to sense anten= na current or voltage, which would also take care of phase shifts from variab= le antenna tuning=2E Then SpecLab can do a phase comparison to a GPS-referenced internal generator, and steer the frequ= ency of an independent output oscillator to bring the radiated signal = ;back to the correct phase=2E
 =
If you want t= o experiment with this method, you can download the configuration file
which generat= es a 8270 Hz stabilised signal=2E To see how it works, take a look at the circuit diagram in:
http://dl=2Edropboxuserc= ontent=2Ecom/u/26404526/screenshot_VLF_TX_1pps_PLL=2Ejpg
 =
The output si= gnal is generated by the digimode terminal block, which can be set up either for a continuous carrier, or= for QRSS or Opera modulation if you want=2E It feeds the DAC and the power ampli= fier through L5=2E The output is brought back to the left input (L1) an= d fed to the "E" channel of a colour-DF spectrogram=2E The right channel (R= 1) gets the 1pps signal from the GPS which is used for samplerate lo= ck=2E Lacking an appropriate GPS unit, I'm not using NMEA timestamps here, bu= t you could chose so if your unit provides serial data with proper timing=2E
 =
The stea= dy reference frequency is provided by the test signal generator - this is where you enter your desired o= utput frequency=2E It is fed to the second "H" channel of the spectrogram thr= ough R5=2E The colour (azimuth) of the trace gives an indication of the phase difference between L1 and R5=2E
 =
The phase loc= k is implemented as a macro in conditional actions: Every 200 ms, it checks whether there is a valid p= robe signal at L1, and is so, it shifts the digimode frequency wit= hin +-0=2E18 Hz according to the phase difference=2E Check this by turmning= the DAC off and on: The trace comes back on with an arbitrary col= our, but  it will always revert to green (180°) within about three seconds=2E 
 =
So to get sta= rted,
- set up= the analog loop path and the 1-pps, 
- load VLF_TX= _1pps_PLL=2Eusr,
- change the&= nbsp;test signal generator frequency from Uwe's 8270=2E004 to yours,
- set th= e digimode teminal to send unmodulated test tone at TX frequency=2E
- enjoy!
 =
Hope this may= be useful=2E
 =
Best 73,
Markus (DF6NM= )
 =
=
Sent: Sunday, January 19, 2014 7:01 PM
Subject: Re: DJ8WX 8270=2E004 Hz - transmit phase correction?
<= span style=3D"font-family: arial; font-size: 13px;">
Hello Markus and all,

Am 19=2E01=2E2014 18:43, schrieb Markus Vester:
30 dB =2E=2E=2E= not too bad, is it?
 
S= till wondering about the nature of those transmit glitches=2E Assuming perfect GPS sync, all possible interruptions in the input data stream cou= ld be detected by the timestamp identification=2E But there is stil= l a chance for undetected buffer underruns in the sound output=2E = ;Would that affect the phase permanently? Or would the average fill state= of the FIFO buffering eventually be pulled back to the original lag (probably not)?=2E
 
I= have been pondering a scheme where one audio channel is getting 1pps while the other is used to sample the transmitter output, eg with a small pickup loop= =2E That way all phase variations in the transmit chain would be caught, and the software oscillator could be steered to revert to the original= phase within a few seconds=2E With timestamping, we could even prescribe absolute phase, allowing comparative measurements a= cross different sessions many days apart=2E
 
W= olf what do you think? If it makes sense, I might try to implement something based on the Sndinput / Sndoutpt combo=2E 
Yes, certainly=2E If there was a drop-out of the audio output, we cannot be sure if the l= atency between 'application' and the arrival of the sample at the D/A-converte= r remains exactly the same=2E Observing the phase of the *radiated signal* and st= eering the signal generated by software to get the phase 'back where it belongs' w= ould be better because it would also compensate phase deviations caused by the = antenna itself=2E

Have a nice evening,
  Wolf =2E

B= est 73,
M= arkus
 
------75BB84ADB15A487F8345488BE2C30567--