Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, HTML_MESSAGE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: : mailn 1480; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id v75Jg7kG013227 for ; Sat, 5 Aug 2017 21:42:09 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1de4tw-0003sY-QD for rs_out_1@blacksheep.org; Sat, 05 Aug 2017 20:38:20 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1de4tp-0003sP-NP for rsgb_lf_group@blacksheep.org; Sat, 05 Aug 2017 20:38:13 +0100 Received: from mout02.posteo.de ([185.67.36.66]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1de4ti-0000jF-N8 for rsgb_lf_group@blacksheep.org; Sat, 05 Aug 2017 20:38:12 +0100 Received: from submission (posteo.de [89.146.220.130]) by mout02.posteo.de (Postfix) with ESMTPS id 504F920A9B for ; Sat, 5 Aug 2017 21:38:04 +0200 (CEST) Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 3xPvGM4zzhz10HW for ; Sat, 5 Aug 2017 21:38:03 +0200 (CEST) Message-ID: <59861E9A.8040806@posteo.de> Date: Sat, 05 Aug 2017 21:38:02 +0200 From: DK7FC 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 References: <59858CB7.3000202@posteo.de> <15db2643c6f-5f13-23c2@webprd-m101.mail.aol.com> <014301d30e1c$b777ef00$2667cd00$@comcast.net> In-Reply-To: <014301d30e1c$b777ef00$2667cd00$@comcast.net> X-Scan-Signature: 17acae084404f211678801ec6cbf7d97 Subject: Re: VLF: Carrier on 3675.005 Hz Content-Type: multipart/alternative; boundary="------------050509080909030002040806" 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 2.75 Status: RO X-Status: X-Keywords: X-UID: 12339 This is a multi-part message in MIME format. --------------050509080909030002040806 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hello Jim! Am 05.08.2017 20:57, schrieb hvanesce@comcast.net: > > Congratulations Stefan, Markus and DL0AO team! > > Is this the first far-field link between 3.000 kHz and 4.000 kHz? > Yes it is, as far as i know. Or at least it is the first detection over a distance of > 1 wavelength. The far field begins at 13 km distance. I doubt that this was done before. Now the distance is 226 km, http://k7fry.com/grid/?qth=JN49IK00WD&from=JN59VK53NK or 2.77 wavelengths. > > Another great data point in the previously uncharted and rough terrain > of 2 kHz - 4 kHz, 100 km - 1000 km. > Yes this is certainly an interesting point in the spectrum down to DC and i am looking forward to see some diurnal signal level changes on that grabber. At that bandwidth and/or scroll rate and the QRN which can vary by 20 dB and more it won't be easy to tell to much from the spectrogram however... BTW where is Paul and Jacek? Jacek often asked when i will do something below 5.17 kHz. Now it is the time! But certainly not the best time in the year for such tests :-) 73, Stefan > Analytical and computational estimates of path loss 2 kHz - 4 kHz, 100 > km - 1000 km are at best somewhat (to considerably) speculative for > lack of data, so I’d venture that the DK7FC/DF6NM/DL0AO team, and all > those who provided receivers, transmitters and processing for prior > tests 2 kHz - 6 kHz*, 100 km - 1000 km, have done valuable pioneering > work. > > (great work in hardware and processing, and especially pioneering work > in characterization of propagation in a little-understood and > not-too-friendly propagation realm 2 kHz - 4 kHz, 100 km - 1000 km) > > From a spectator’s perspective this is very exciting. > > * (5 kHz and 6 kHz tests helping to assess an upper boundary for > the complicated 2 kHz - 4 kHz, 100 km - 1000 km space) > > (Much credit also to transmitter, receiver and processing work > at 970 Hz making the interesting sub-kHz world accessible) > > Jim AA5BW > > *From:* owner-rsgb_lf_group@blacksheep.org > [mailto:owner-rsgb_lf_group@blacksheep.org] *On Behalf Of *Markus Vester > *Sent:* Saturday, August 5, 2017 8:35 AM > *To:* rsgb_lf_group@blacksheep.org > *Subject:* Re: VLF: Carrier on 3675.005 Hz > > Yes the signal is definitely making it to Amberg! This is a fine > result of mutual collaboration: Stefan DK7FC erecting the transmit > facility and posing the low frequency challenge, the DL0AO team > (specifically Tom DK1IS and Bernd DF9RB) laying out antennas in a > quiet forest around their club station and installing dedicated > hardware, and myself trying to tame 14 SpecLab instances without > introducing too many errors. > > The first indication of a 3675.005 Hz peak appeared already a couple > of days ago on the E-probe antenna, and is still shown in > the ultra-narrow 9.3 uHz window (waiting to be updated later tonight). > Since yesterday, antenna and GPS connections have been greatly > optimized, and the 31 uHz peak appeared early this morning > after "only" 9 hours of averaging. > > Best 73, > Markus (DF6NM) > > > -----Ursprüngliche Mitteilung----- > Von: DK7FC > > An: rsgb_lf_group > > Verschickt: Sa, 5. Aug 2017 11:17 > Betreff: Re: VLF: Carrier on 3675.005 Hz > > VLF, > > After nearly 8 days the carrier is still on the air without an > interruption, despite occasional thunderstorms :-) > It looks like the SNR is suffering by summer QRN, as expected. > > The stable carrier was good for doing local tests with my > Raspi+Octo-soundcard. The system is now completely configured > including system time setting via the GPS module. I recorded a few > days from the carrier, converted the data files into wav, reprocessed > them in SpecLab: The carrier is stable and on the expected frequency, > so the sample rate correction via vlfrx tools seems to work. > > Forthermore i corrected some bugs in the circuit of my portable RX > loop preamp for VLF (must have been late in the night when i built it > up a few months ago). Now the noise is much lower. It looks promising! > So it is time for a portable VLF experiment in the far field, just to > check the system more seriously. > > The crew of DL0AO has built up and optimised their VLF system to > receive the weak 3675.005 Hz carrier in abt 220 km distance. Looks > like there is something on their cardioidal spectrogram pointing to West, > http://df6nm.bplaced.net/dl0ao/VLFgrabber/vlfgrabber_dl0ao_test.htm > Something like 10 dB SNR in 31 uHz. That's not so bad! > > I will run it for some more time until the trace is a bit longer. Then > in some days i like to start transmitting an EbNaut message on that > frequency which can be stacked until a decode appears. Markus has > developed a tool for windows to do the stacking, maybe it works in > that experiment... It will also be a test to see if i can decode the > message from my own recording using vlfrx tools, an important step to > pass... > > So far so good. What are YOUR projects you are currently working on, > LF/MF/VLF related? > > 73, Stefan > > > Am 28.07.2017 16:56, schrieb DK7FC: > > Hi VLF, > > I'm back from LF for a while and built up my large VLF coil which was > used on 2970 Hz in the beginning of the year. Actually it is under > maintenance, one of the six stacks has to be replaced. It is already > dismantled but the new wire is not yet wound on the 250 mm diameter > PVC tube again. > So now the resonance is higher! I didn't know where it is and just > connected the coil and scanned the frequency downwards. Near 3685 Hz i > found a maximum of the antenna. Since the Q is not extremely high, i > decided to tune to 3675 Hz and added the usual 5 mHz offset, to stay > away from multiples of 1 Hz. > > So, now *since 14:40 UTC* a carrier is running on *3675.005 Hz*. The > antenna current is *170 mA*. I estimate the *ERP is just 3 uW*! > > I guess this is a first amateur radio transmission on the *82 km* band > and that class of ERP (?). > > Hopefully the coil will hold the *15.5 kV* with just 5 stacks of > windings. It's inductance is *3.9 H* in the moment! > > I intend to run the carrier for at least a few days, depending on the > feedback. > > Good luck for the VLF experts! > > 73, Stefan > > PS: A 424 uHz RDF spectrogram is running at > http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html > (First pixel appears in 30 minutes) > --------------050509080909030002040806 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit Hello Jim!

Am 05.08.2017 20:57, schrieb hvanesce@comcast.net:

Congratulations Stefan, Markus and DL0AO team!

 

Is this the first far-field link between 3.000 kHz and 4.000 kHz?

Yes it is, as far as i know. Or at least it is the first detection over a distance of > 1 wavelength. The far field begins at 13 km distance. I doubt that this was done before.
Now the distance is 226 km, http://k7fry.com/grid/?qth=JN49IK00WD&from=JN59VK53NK or 2.77 wavelengths.

 

Another great data point in the previously uncharted and rough terrain of 2 kHz - 4 kHz, 100 km - 1000 km.

Yes this is certainly an interesting point in the spectrum down to DC and i am looking forward to see some diurnal signal level changes on that grabber. At that bandwidth and/or scroll rate and the QRN which can vary by 20 dB and more it won't be easy to tell to much from the spectrogram however...

BTW where is Paul and Jacek? Jacek often asked when i will do something below 5.17 kHz. Now it is the time! But certainly not the best time in the year for such tests :-)

73, Stefan


 

Analytical and computational estimates of path loss 2 kHz - 4 kHz, 100 km - 1000 km are at best somewhat (to considerably) speculative for lack of data, so I’d venture that the DK7FC/DF6NM/DL0AO team, and all those who provided receivers, transmitters and processing for prior tests 2 kHz - 6 kHz*, 100 km - 1000 km, have done valuable pioneering work.


 

(great work in hardware and processing, and especially pioneering work in characterization of propagation in a little-understood and not-too-friendly propagation realm 2 kHz - 4 kHz, 100 km - 1000 km)

 

From a spectator’s perspective this is very exciting.

 

 

   *  (5 kHz and 6 kHz tests helping to assess an upper boundary for the complicated 2 kHz - 4 kHz, 100 km - 1000 km space)

       (Much credit also to transmitter, receiver and processing work at 970 Hz making the interesting sub-kHz world accessible)  

 

 

Jim AA5BW

 

 

 

From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Markus Vester
Sent: Saturday, August 5, 2017 8:35 AM
To: rsgb_lf_group@blacksheep.org
Subject: Re: VLF: Carrier on 3675.005 Hz

 

Yes the signal is definitely making it to Amberg! This is a fine result of mutual collaboration: Stefan DK7FC erecting the transmit facility and posing the low frequency challenge, the DL0AO team (specifically Tom DK1IS and Bernd DF9RB) laying out antennas in a quiet forest around their club station and installing dedicated hardware, and myself trying to tame 14 SpecLab instances without introducing too many errors.

The first indication of a 3675.005 Hz peak appeared already a couple of days ago on the E-probe antenna, and is still shown in the ultra-narrow 9.3 uHz window (waiting to be updated later tonight). Since yesterday, antenna and GPS connections have been greatly optimized, and the 31 uHz peak appeared early this morning after "only" 9 hours of averaging.

Best 73,
Markus (DF6NM)


-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Sa, 5. Aug 2017 11:17
Betreff: Re: VLF: Carrier on 3675.005 Hz

VLF,

After nearly 8 days the carrier is still on the air without an interruption, despite occasional thunderstorms :-)
It looks like the SNR is suffering by summer QRN, as expected.

The stable carrier was good for doing local tests with my Raspi+Octo-soundcard. The system is now completely configured including system time setting via the GPS module. I recorded a few days from the carrier, converted the data files into wav, reprocessed them in SpecLab: The carrier is stable and on the expected frequency, so the sample rate correction via vlfrx tools seems to work.

Forthermore i corrected some bugs in the circuit of my portable RX loop preamp for VLF (must have been late in the night when i built it up a few months ago). Now the noise is much lower. It looks promising! So it is time for a portable VLF experiment in the far field, just to check the system more seriously.

The crew of DL0AO has built up and optimised their VLF system to receive the weak 3675.005 Hz carrier in abt 220 km distance. Looks like there is something on their cardioidal spectrogram pointing to West,
http://df6nm.bplaced.net/dl0ao/VLFgrabber/vlfgrabber_dl0ao_test.htm
Something like 10 dB SNR in 31 uHz. That's not so bad!

I will run it for some more time until the trace is a bit longer. Then in some days i like to start transmitting an EbNaut message on that frequency which can be stacked until a decode appears. Markus has developed a tool for windows to do the stacking, maybe it works in that experiment... It will also be a test to see if i can decode the message from my own recording using vlfrx tools, an important step to pass...

So far so good. What are YOUR projects you are currently working on, LF/MF/VLF related?

73, Stefan


Am 28.07.2017 16:56, schrieb DK7FC:

Hi VLF,

I'm back from LF for a while and built up my large VLF coil which was used on 2970 Hz in the beginning of the year. Actually it is under maintenance, one of the six stacks has to be replaced. It is already dismantled but the new wire is not yet wound on the 250 mm diameter PVC tube again.
So now the resonance is higher! I didn't know where it is and just connected the coil and scanned the frequency downwards. Near 3685 Hz i found a maximum of the antenna. Since the Q is not extremely high, i decided to tune to 3675 Hz and added the usual 5 mHz offset, to stay away from multiples of 1 Hz.

So, now since 14:40 UTC a carrier is running on 3675.005 Hz. The antenna current is 170 mA. I estimate the ERP is just 3 uW!

I guess this is a first amateur radio transmission on the 82 km band and that class of ERP (?).

Hopefully the coil will hold the 15.5 kV with just 5 stacks of windings. It's inductance is 3.9 H in the moment!

I intend to run the carrier for at least a few days, depending on the feedback.

Good luck for the VLF experts!

73, Stefan

PS: A 424 uHz RDF spectrogram is running at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html (First pixel appears in 30 minutes)

--------------050509080909030002040806--