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=-1.7 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_40_50,HTML_MESSAGE,HTML_TITLE_EMPTY 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 t5RD5iWU001867 for ; Sat, 27 Jun 2015 15:05:44 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Z8pkX-0003Bp-CH for rs_out_1@blacksheep.org; Sat, 27 Jun 2015 14:02:25 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Z8pkW-0003Bg-Ii for rsgb_lf_group@blacksheep.org; Sat, 27 Jun 2015 14:02:24 +0100 Received: from omr-m5.mx.aol.com ([64.12.232.237]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.85) (envelope-from ) id 1Z8pkT-00020s-NJ for rsgb_lf_group@blacksheep.org; Sat, 27 Jun 2015 14:02:23 +0100 Received: from mtaout-mbc01.mx.aol.com (mtaout-mbc01.mx.aol.com [172.26.221.141]) by omr-m5.mx.aol.com (Outbound Mail Relay) with ESMTP id 574B338000098 for ; Sat, 27 Jun 2015 09:02:19 -0400 (EDT) Received: from White (ipb21bee4a.dynamic.kabel-deutschland.de [178.27.238.74]) by mtaout-mbc01.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id 6866738000093 for ; Sat, 27 Jun 2015 09:02:16 -0400 (EDT) Message-ID: From: "Markus Vester" To: References: <8D27C7D3E7D6748-14A8-F71B3@webmail-vm149.sysops.aol.com> <558D8FEC.2090102@posteo.de> <7D39EA36066C485998744D9E994DAC52@White> <558DC2A1.2040608@posteo.de> <558E968E.7080101@posteo.de> Date: Sat, 27 Jun 2015 15:02:14 +0200 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=1435410139; bh=MvC7P7I6XvieiiaZSceBmPinB/FP8hCbJng9DDqe54U=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=UlW5Wo4UIb3galFC0CvyGaGXgCkP99MRhvxC0ted7Aqju0YJfkeUGOmy+2f/naNrJ v1XeppZrgy0sGdxSvySnQDCnmwYkTdEBdQBfowYZTOWgsbreoqCwiHhwd3P+/iIYho drdXQwQskU3Oz6dCTVQKXPOCUNMELxaQhWzIdXak= x-aol-sid: 3039ac1add8d558e9ed812dd X-AOL-IP: 178.27.238.74 X-Scan-Signature: af9871cf36151fc2a83003e0c95f57d1 Subject: Re: LF: Heidelberg remote MF receiver Content-Type: multipart/alternative; boundary="----=_NextPart_000_0006_01D0B0EA.409D9790" 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: 3543 Dies ist eine mehrteilige Nachricht im MIME-Format. ------=_NextPart_000_0006_01D0B0EA.409D9790 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Stefan, just tried some more WSPR between 12:44 and 13 UT, but with the current = intense QRN there's just no chance. In the morning, there were only = sparse flashes (maybe 1 to 5 per WSPR sequence), which would have been = easily cured by noise blanking. I was actually wondering why the decodes = were so much affected by a small number of spikes. 73, Markus From: DK7FC=20 Sent: Saturday, June 27, 2015 2:26 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Heidelberg remote MF receiver Hello Markus,=20 Most interesting, thanks! Let us use the strong QRN to check if SL does = perform better if the SpecLab NB is used in front of WSPR. Ah i could = use a 2nd instance for a 2nd instance of WSPR(2), feeding VAC1 to VAC3 = including the NB, while the current instance feeds VAC1 to VAC2 without = a NB to WSPR(1). Just continue to run your WSPR in 100% mode, if you like :-) 73, Stefan Am 27.06.2015 14:12, schrieb Markus Vester:=20 Hi Stefan, since last night your two receivers have been operating without = interruption, allowing to compare results from your two grabbers. - WSPR: Last night, 21 of my low-power WSPR transmissions were decoded = simultaneously by DK7FC/p and DK7FC. On average, the /p receiver had a = 5.67 dB SNR advantage. For my direction, the receive loop and the T = antenna seem to have performed similarly.=20 Today between 11.08 and 11:24 I sent some more SNR sequences with = higher power (0.1 W EMRP), expecting a higher SNR difference in the = lower daytime background noise. However half of the transmissions were = not decoded on either grabber, and those that were picked up by both = showed only a small advantage. This is probably due to the strong QRN = from flashes from a nearby thunderstorm, which for some reason are = heavily affecting WSPR decodes. It might help to use effective noise = blanking in the SpecLab instance which is feeding WSPR. Anyway if the = statics happen to ease off I will attempt another daytime comparison = later today.=20 - DFCW: Between the thunderstorms this morning, my 2 mW DFCW-60 = transmission was definitely picked up more clearly on the /p receiver. = However this one suffers from a large frequency drift (10 Hz upwards), = which appears to be strongly correlated with RasPi core temperature and = solar chargerate plots - so presumably just crystal temperature. In = addition, some of the dashes appeared slightly disrupted, either by = audio glitches or by fast and small LO frequency jitter. During the = storms, my impression was that noise blanking in the narrow spectrograms = could also be optimized a bit. There are a couple of QRM lines which are always commonly visible on = both receivers (472.36 and 477.74 kHz). I am wondering whether you could = perhaps use them as references for a SpecLab frequency drift correction? BTW. I have taken a number of screenshots from your grabbers which I = have copied to our private dropbox folder. All the best, Markus (DF6NM) =20 From: Markus Vester=20 Sent: Saturday, June 27, 2015 12:39 AM To: rsgb_lf_group@blacksheep.org=20 Subject: LF: Heidelberg remote MF receiver Hi Stefan, it looks like signals are consistently better on your remote receiver, = perhaps around 6 dB or something in that ballpark. So it seems that all = your work is finally paying off! I'm looking forward to see a daytime = comparison tomorrow. My guess is that the main contributor to frequency variation would be = the 461 kHz LO crystal rather than the soundcard samplerate. Anyway = exchanging the 12 MHz crystal may possibly have no effect at all, = because the samplerate of USB soundcards is usually derived from the bus = master clock (ie the RasPi) and not from the internal crystal on the = dongle.=20 Best 73, Markus (DF6NM) From: DK7FC=20 Sent: Friday, June 26, 2015 11:22 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: 476.181 kHz from indoor loop Hi Markus,=20 Really? Wonderful! :-) And the stream is still running. I'll watch it = some days now to see if all Raspi problems are gone, then the next = part-project is the RX. Meanwhilethe sky wave is present and i can see you quite strong in = DFCW-30 with your 3 mW ERP from the loop. I missed watching you on the = remote grabber in daytime. What was the SNR ralative to the city = location? Same or better? I switched back to the T antenna in the = afternoon. It would be interesting so see you on my loop. On 21:19 i = switched to the loop! Ah and now you can see the drift of my RX which is quite visible, but = still uncritical for QRSS-30 or WSPR. I thought about changing the 12 MHz xtal of the soundcard. It is the = cheap SMD xtal which has 100 ppm/K but there are other versions with 30 = ppm/K. Maybe an idea, they are no expensive and still compact... 73, Stefan Am 26.06.2015 21:04, schrieb Markus Vester:=20 Hi Stefan, good to see the remote station working nicely now. >> but don't see you ...yes you do ;-) There is a slight frequency offset in the remote = grabber which had put me out of your QRSS-30 band. I now switched to my = "heritage" QRG 136172.5 ahem 476172.5 Hz, and voila there it is, loud = and clear. Currently still on the low Marconi, also about 2 mW EMRP. The = relatively strong coupling to the LF grabber E-field antenna produced = some aliases and noise there, which have been mitigated by a 475 kHz = Saugkreis (trap) - same as in old AM radios ;-)=20 73, Markus From: DK7FC=20 Sent: Friday, June 26, 2015 7:46 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: 476.181 kHz from indoor loop Hi Markus,=20 Thanks for your DFCW-30 transmission. I can see you clearly in = daytime on my RX in the city! However i can't see you on my RX is the = garden! The remote system seems to run stable now, at least for a longer = time then in the last 3 days :-)=20 = http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_remote_Grabber.html I switched between a T antenna and a loop beaming 300/120 deg but = don't see you. It appears that the hill between us is (my garden is on = the hill side, the city antenna is more distant to the hill) actually = reducing the SNR. So it also reduces QRN from the east and favours the = west. But i would prefer an omnidirectional pattern :-/ 73, Stefan Am 24.06.2015 12:11, schrieb Markus Vester:=20 I am currently running a DFCW-60 beacon on 476.181 kHz, using the = same 10m^2 indoor transmit loop as previously on LF. With 35 Watts of RF = input, estimated radiated power is around 2 mW, with lobes pointing west = and east. The daytime groundwave signal is visible in the bottom panel of = the DK7FC MF grabber. Going by the CCIR plots for 3 mS/m conductivity, = the groundwave attenuation for this distance would be about 23 dB in = excess off lossless 1/r propagation, resulting in approximately 0.2 uV/m = in Heidelberg.=20 Best 73, Markus (DF6NM) ------=_NextPart_000_0006_01D0B0EA.409D9790 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Stefan,
 
just tried some more WSPR between 12:44 = and 13 UT,=20 but with the current intense QRN there's just no chance. In the morning, = there=20 were only sparse flashes (maybe 1 to 5 per WSPR sequence), which would = have been=20 easily cured by noise blanking. I was actually wondering why the=20 decodes were so much affected by a small number of = spikes.
 
73, Markus
 

From: DK7FC
Sent: Saturday, June 27, 2015 2:26 PM
To: rsgb_lf_group@blacksheep.org= =20
Subject: Re: LF: Heidelberg remote MF = receiver

Hello Markus,

Most interesting, thanks! Let us = use the=20 strong QRN to check if SL does perform better if the SpecLab NB is used = in front=20 of WSPR. Ah i could use a 2nd instance for a 2nd instance of WSPR(2), = feeding=20 VAC1 to VAC3 including the NB, while the current instance feeds VAC1 to = VAC2=20 without a NB to WSPR(1).

Just continue to run your WSPR in 100% = mode, if=20 you like :-)

73, Stefan

Am 27.06.2015 14:12, schrieb = Markus=20 Vester:=20
Hi Stefan,
 
since last night your two receivers = have been=20 operating without interruption, allowing to compare results from = your two=20 grabbers.
 
- WSPR: Last night, 21 of = my low-power=20 WSPR transmissions were decoded simultaneously by DK7FC/p and DK7FC. = On=20 average, the /p receiver had a 5.67 dB SNR advantage. For my = direction, the receive loop and the T antenna seem to have = performed=20 similarly.
 
Today between=20 11.08 and 11:24 I sent some more SNR = sequences with higher=20 power (0.1 W EMRP), expecting a higher SNR difference in the lower = daytime=20 background noise. However half of the transmissions were not = decoded on=20 either grabber, and those that were picked up by both showed only a = small=20 advantage. This is probably due to the strong QRN from flashes from a = nearby=20 thunderstorm, which for some reason are heavily affecting WSPR = decodes.=20 It might help to use effective noise blanking in the SpecLab = instance=20 which is feeding WSPR. Anyway if = the=20 statics happen to ease off I will attempt another daytime = comparison=20 later today.
 
- DFCW: Between the thunderstorms = this=20 morning, my 2 mW DFCW-60 transmission was definitely picked up = more=20 clearly on the /p receiver. However this one suffers from a large = frequency drift (10 Hz upwards), which appears to be strongly = correlated with=20 RasPi core temperature and solar chargerate plots - so = presumably just=20 crystal temperature. In addition, some of the = dashes appeared=20 slightly disrupted, either by audio glitches or by fast and small = LO=20 frequency jitter. During the storms, my impression was that noise = blanking in the narrow spectrograms could also be optimized a=20 bit.
 
There are a couple of QRM lines which = are always=20 commonly visible on both receivers (472.36 and 477.74 kHz). I am=20 wondering whether you could perhaps use them as references for a = SpecLab=20 frequency drift correction?
 
BTW. I have taken a number = of=20 screenshots from your grabbers which I have copied to our = private=20 dropbox folder.
 
All the best,
Markus (DF6NM)

 
From: Markus = Vester=20
Sent: Saturday, June 27, 2015 12:39 AM
Subject: LF: Heidelberg remote MF = receiver

Hi Stefan,
 
it looks like signals are = consistently=20 better on your remote receiver, perhaps around 6 dB or something = in that=20 ballpark. So it seems that all your work is finally paying = off! I'm=20 looking forward to see a daytime comparison = tomorrow.
 
My guess is that the main contributor = to=20 frequency variation would be the 461 kHz LO crystal rather than the = soundcard=20 samplerate. Anyway exchanging the 12 MHz crystal may possibly have no = effect=20 at all, because the samplerate of USB soundcards is usually derived=20 from the bus master clock (ie the RasPi) and not from the = internal=20 crystal on the dongle. 
 
Best 73,
Markus (DF6NM)
 

From: DK7FC
Sent: Friday, June 26, 2015 11:22 PM
Subject: Re: LF: 476.181 kHz from indoor = loop

Hi Markus,

Really? Wonderful! :-) And the = stream is=20 still running. I'll watch it some days now to see if all Raspi = problems are=20 gone, then the next part-project is the RX.
Meanwhilethe sky wave = is=20 present and i can see you quite strong in DFCW-30 with your 3 mW ERP = from the=20 loop. I missed watching you on the remote grabber in daytime. What was = the SNR=20 ralative to the city location? Same or better? I switched back to the = T=20 antenna in the afternoon. It would be interesting so see you on my = loop. On=20 21:19 i switched to the loop!
Ah and now you can see the drift of = my RX=20 which is quite visible, but still uncritical for QRSS-30 or = WSPR.

I=20 thought about changing the 12 MHz xtal of the soundcard. It is the = cheap SMD=20 xtal which has 100 ppm/K but there are other versions with 30 ppm/K. = Maybe an=20 idea, they are no expensive and still compact...

73, = Stefan

Am=20 26.06.2015 21:04, schrieb Markus Vester:=20
Hi Stefan,
 
good to = see the remote=20 station working nicely now.
 
>> but don't see = you
 
...yes you do ;-) There = is a slight=20 frequency offset in the remote grabber which had put me out = of your=20 QRSS-30 band. I now switched to my = "heritage" QRG 136172.5=20 ahem 476172.5 Hz, and voila there it is, loud = and clear.
 
Currently still on the low = Marconi, also=20 about 2 mW EMRP.  The relatively strong coupling to = the LF=20 grabber E-field antenna produced some aliases and noise there, = which=20 have been mitigated by a 475 kHz Saugkreis (trap) - same as = in old AM=20 radios ;-)
 
 73, Markus
 

From: DK7FC
Sent: Friday, June 26, 2015 7:46 PM
Subject: Re: LF: 476.181 kHz from indoor = loop

Hi Markus,

Thanks for your DFCW-30 = transmission. I=20 can see you clearly in daytime on my RX in the city! However i can't = see you=20 on my RX is the garden! The remote system seems to run stable now, = at least=20 for a longer time then in the last 3 days :-)
http://www.iup.uni-heidelberg.de/schaefer_vlf/DK= 7FC_remote_Grabber.html
I=20 switched between a T antenna and a loop beaming 300/120 deg but = don't see=20 you. It appears that the hill between us is (my garden is on the = hill side,=20 the city antenna is more distant to the hill) actually reducing the = SNR. So=20 it also reduces QRN from the east and favours the west. But i would = prefer=20 an omnidirectional pattern :-/

73, Stefan

Am = 24.06.2015 12:11,=20 schrieb Markus Vester:=20
I am currently running a DFCW-60 beacon on 476.181 kHz, = using=20 the same 10m^2 indoor transmit loop as previously on LF. With = 35=20 Watts of RF input, estimated radiated power is around 2=20 mW, with lobes pointing west and east.
 
The daytime groundwave signal is visible in the bottom panel = of the=20 DK7FC MF grabber. Going by the CCIR plots for 3 mS/m = conductivity,=20 the groundwave attenuation for this distance would be about 23 dB = in=20 excess off lossless 1/r propagation, resulting in approximately = 0.2 uV/m=20 in Heidelberg. 
 
Best 73,
Markus (DF6NM)
=

 
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