Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id w3DHI9OO008421 for ; Fri, 13 Apr 2018 19:18:11 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1f72Gg-000288-A3 for rs_out_1@blacksheep.org; Fri, 13 Apr 2018 18:13:46 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1f72Gd-00027o-Do for rsgb_lf_group@blacksheep.org; Fri, 13 Apr 2018 18:13:43 +0100 Received: from resqmta-ch2-01v.sys.comcast.net ([2001:558:fe21:29:69:252:207:33]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1f72GX-0000Ki-Of for rsgb_lf_group@blacksheep.org; Fri, 13 Apr 2018 18:13:42 +0100 Received: from resomta-ch2-19v.sys.comcast.net ([69.252.207.115]) by resqmta-ch2-01v.sys.comcast.net with ESMTP id 72FufZ630tYHF72GSfauhy; Fri, 13 Apr 2018 17:13:32 +0000 X-DKIM-Result: Domain=comcast.net Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20161114; t=1523639612; bh=Atahv5qLkN78BLUF22+W3BxyjYnw9403hlTQuDUNOC0=; h=Received:Received:From:To:Subject:Date:Message-ID:MIME-Version: Content-Type; b=doMYioTX34RxAymdANgQGcy4FVvoNL/lXVIIlRcG0P2Mr4pZj/8R1t0sqE8Ce/oeu UKvF08bsXLgTzh1+bwBP8xJooHHFZSMOmjb+QXqVZexqtwlhKrscQIAgfBbWMtTMx3 ZwVB814tilQ0xnSmxXa8a1FosqcOt/iwFDADxCyx4FA7jp25jyaeSQV09x3PT/Rzdl 8frec4nGT7zE6PtupfdI3XVxUKA2b1Z6yaWDUFBKNsM9C9e6SMAY1P9eK2tNGNc5hP fwawVt9GlpUUaAdL33V6SDhK8Px7C4Z4UNwyGlpF3wPj4XiRbLO/fLbWvs6/zE+jhu NnydB0PfkmE1g== Received: from Owner ([IPv6:2601:140:8500:7f9f:78f6:dd:b547:d008]) by resomta-ch2-19v.sys.comcast.net with SMTP id 72GOffBEJMBoJ72GPfgnox; Fri, 13 Apr 2018 17:13:30 +0000 From: To: References: <15f68ccfd03-c09-1dcf0@webjas-vaa134.srv.aolmail.net> <40168a26-8991-6998-e541-585a8575ad32@abelian.org> <59FCF49B.9050703@posteo.de> <5A06DAE4.9030301@posteo.de> <5A072F91.1050406@posteo.de> <5A083D50.2080105@posteo.de> <34e5e647-caf1-6184-9ab5-9d293486994f@abelian.org> <5A085F65.3060409@posteo.de> <5A0889B1.3020701@posteo.de> <5A09B458.1040700@posteo.de> <5A0DC9D1.1050706@posteo.de> <5A6A4D33.5020502@posteo.de> <5A6CB04D.7080006@posteo.de> <5A6D1532.8090206@posteo.de> <5A6E09B4.2090301@posteo.de> <5A71C4F8.50508@posteo.de> <5A7C462A.20905@posteo.de> <5ACE09F4.50507@posteo.de> In-Reply-To: <5ACE09F4.50507@posteo.de> Date: Fri, 13 Apr 2018 13:13:10 -0400 Message-ID: <02d401d3d34a$bc177190$344654b0$@comcast.net> MIME-Version: 1.0 X-Mailer: Microsoft Outlook 14.0 Thread-Index: AQEYUAzT6pGNxymcBczZWqkEl/pIIwHwsMvTAXYvohMCcO6qoQJYTcF8AeqNtwEBuzsvLgHAhHzDAY8+/x4BpOSH9QG5ghHSAYeY+XQCoAqZEwHVWYa9Af5luCoBgLIVowJIqcr0Ao9jjWQCDQTR/QFu7dhKpFNM6iA= Content-Language: en-us X-CMAE-Envelope: MS4wfHjG6WS9SGVJm5uBXcCbsYs6JUYkTNtVs85k6+dxejkjmsXoeGT4fw4UC5PUNsstzpTCsyHExcKSWrjPMiBqaW5W66Nr8oXFqznwbd+4ShL0qsulF/h+ H1QHoRb/gYQHe0Z22xbBCXgQMuqOKr5O1hs= X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hello Stefan, Congratulations on your 40.5 km 970 Hz record with loop-only receiver; and the successful preparation that preceded. Do you think that you might have also overcome a receiver polarization challenge in the process? [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (hvanesce[at]comcast.net) 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_KAM_HTML_FONT_INVALID BODY: Test for Invalidly Named or Formatted Colors in HTML 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: f3bc6f10d05216e9eca6fe092612a1dd Subject: RE: ULF: New experiment on 970 Hz 3/3 summary Content-Type: multipart/alternative; boundary="----=_NextPart_000_02D5_01D3D329.35084290" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_20_30,HTML_MESSAGE, NO_REAL_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 This is a multipart message in MIME format. ------=_NextPart_000_02D5_01D3D329.35084290 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hello Stefan, =20 Congratulations on your 40.5 km 970 Hz record with loop-only receiver; = and the successful preparation that preceded. =20 Do you think that you might have also overcome a receiver polarization = challenge in the process?=20 =20 With a surface TX loop to RX loop near field link I keep both loop = planes vertical (both loop axes horizontal), with the RX loop axis = pointing at the transmitter (RX loop plane facing the transmitter). With a surface TX loop to RX loop far field link I keep both loop planes = vertical (both loop axes horizontal), with the RX loop axis pointing = perpendicular to the transmitter (RX loop plane edge pointing toward the = transmitter). With a TX vertical-antenna to RX loop far field link I keep the RX loop = axis pointing perpendicular to the transmitter (RX loop plane edge = pointing toward the transmitter). =20 I=E2=80=99m not sure what the polarization of your TX antenna would be = at 40.5 km (~ 1/8 wavelength, near the first of the two = near/far-boundary impedance intersections), or what the best RX loop = orientation would be for such TX near-field-boundary signal = polarization. Do you think that your RX loop was fairly well aligned for = the 970 Hz 1/8 wavelength polarization of your TX signal? =20 Congratulations on another important and most interesting (970 Hz = near-far impedance-crossover point) record! =20 73, =20 Jim AA5BW =20 =20 =20 =20 =20 From: owner-rsgb_lf_group@blacksheep.org = [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of DK7FC Sent: Wednesday, April 11, 2018 9:13 AM To: rsgb_lf_group@blacksheep.org Cc: Renato Romero Subject: Re: ULF: New experiment on 970 Hz 3/3 summary =20 Hello ULF friends,=20 Here is the summary of my recent portable experiment on 970.005 Hz.=20 The goal of the experiment was to undoubtly detect my own transmission = in a distance of 40.5 km. The experiment took about 8 days, starting = 30.JAN.2018, 16:30 UTC. For the first 3 days, a carrier was transmitted = on 970.005 Hz, for 48 hours, and then 24 hours on 970.0025 Hz. = Afterwards, a 2 character EbNaut message was transmitted, taking 24 = hours exactly, two times repeated. And finally, a 5 character message = was transmitted, also taking 24 hours, two times repeated. This is the path http://k7fry.com/grid/?qth=3DJN49BK33UG = = &from=3Djn49ik00wd which the 18 nW ERP signal had to cross. Along with the other experiments i've done during that time, it took = nearly two months for me to learn how to operate Paul's vlfrx tools and = to do all the post processing.=20 I had to determine: -The best noise blanker settings,=20 -The best filter shape, bandwidth and center frequency -The optimum hum filter parameter settings -The phase between E field (whip) and H field (loop) -The best mixing coefficients (amplitude, phase) between E and H -The phase difference of the signal between day and night ...all to maximise the SNR of the carrier peak and Eb/N0 of the = messages. Unfortunately the E field was not usable for most of the days. Either = something got damaged on the front end JFET or the shielding effect of = sourrounding trees has been much higher than expected. The performance = of the 84 turn loop antenna having 0.8 m diameter and a low noise preamp = was fine, though not optimal since there were AM broadcast signals = audible during the sunrise and sunset (a resonance on HF, resulting in = an overloaded preamp at times?!). So all in all there were a lot of performace limiting issues. Anyway, the two character message was decoded without much tweaking of = blanker etc. settings. Based on these signals to analyse, along with the = carrier, it was possible to find the best settings to even get a decode = of the 5 character message in the end! The carrier result and the 5 = character message is H field only! Here are the results: Spectrum peak of the 72 hour carrier transmission, combined in one peak: = http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/TR3_Endversion.png= 2 character message: = http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/2ch970Hz40km_E+H.p= ng 5 character message: = http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/5ch970Hz40km.png So let me conclude the experiment was a full success, despite all the = trouble and limitations i had. And it means that more distance can be = expected if the RX system is working as intended! This new distance record of 40.5 km on the 309 km band is still in the = near field for that wave! See = http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/Nahfeld%C3%BCberga= ng.png These are the locations of all experiments done on the 309 km band so = far: = http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/970Hz_bisher.png For the next experiment, i definitively plan to cross the far field = border ( > 49.3 km). The idea is to use about 3 dB more power and a = working RX system and a better location for the E field :-) When doing = it in the summer months, the 3 dB more power will be compensated by QRN = i fear. A photo from the RX site in the snow: = http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/RX_site.jpg A photo showing the data recorder: = http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/Raspi.jpg And the batteries afterwards: = http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/Batt.jpg 73, Stefan PS: Thanks to Paul Nicholson for the support in learning how to use = vlfrx tools! Am 08.02.2018 13:44, schrieb DK7FC:=20 Hello dear friends of the Ultra Low Frequencies, Update: There are a few things to note so far: I made a mistake in the calculation of the ERP. It is not 10 nW but = rather 18 nW. All transmissions seemed to go out as intended. The stream from the = local tree was interrupted almost daily due to lack of solar energy but = at least a few hours came through. From these few hours i got decodes of = each carrier transmissions. I also got decodes of all EbNaut messages. = So things went well from the TX site it seems. The 36 mA antenna current (12 kV antenna voltage) was running for 8 days = without a single interruption. The constructed resonating transformer = has done its job flawlessly. Since i decided to take back the RX equipment on the 7th of February, = there was some more time for another EbNaut message: 06.Feb, 17:30 UTC: EbNaut, 16K21A, 1 char, 90 sec, CRC27 (21:12:00) The experiment stopped at 15:45 UTC. BTW the exact location was = JN49BK33UG That is a = distance of 40.5 km to the TX site. But so far there are no decodes or = traces, so no success so far. The next good step is that the whole RX equipment has still been in its = place, nothing stolen, nothing damaged. The Raspi was still running = after 8 days. The Raspi was supplied by two 12 V / 26 Ah lead gel accus. = They were standing in the snow and discharged to 11.8 V! The two accus = for the preamps of the loop and vertical were still above 12.3 V. So = that was all fine too! Now the stuff is sorted, cleaned and the accus are charging and warming = up again here.=20 I just started the Raspi and checked the data on the 64 GB USB stick. = This looks good and promising, see attachment. And it looks like there = were no timing breaks of the GPS module. For the first time i run the recording using vlfrx tooly by Paul and the = octo soundcard. Also it is the first set of data i have available to = build a cardioid antenna by software... Exciting stuff.=20 The recording process by vlfrx tools saves to a new file each day.=20 Here the files are 7.8 GB large: 2 channels * 24000 = samples/(channel*second) * 16 bit/sample * 3600 seconds/hour * 24 = hours/day * 1/8 Byte/bit * 1/1024 kByte/Byte * 1/1024 MBity/kByte * = 1/1024 GByte/MByte =3D 7.72 GB/day =20 Obviously the recording process was stopped during the last night 03:58 = UTC because the USB stick capacity seems to be just 58 GB actually. The = recording is started/stopped by switching a switch which is connected to = one of the GPIO pins. This is necessary because in the field there is no = monitor and no keyboard of course. At start-up, a scripts is executed = which checks the logic level of the pin where the switch is connected... = During the recording process, a loop is running within this script which = periodically checks the remaining available=20 space of the data carrier. As soon as the remaining space becomes less = than 100 kB, the recording process is stopped. This ensures that there = is still enough space to save the log files which are written at the end = of the recording process. It also ensures that there are no crashes and = unwanted data loss, broken files etc... In a few days i can report about the results, so stay tuned... 73, Stefan Am 31.01.2018 14:30, schrieb DK7FC:=20 Hi all,=20 Since yesterday, ~ 17 UTC, i'm running a new portable experiment on 970 = Hz, or the 309 km band. The receiver site is somewhere in the forest in = JN49BK , a distance of 40 km to = the TX site. I carried a lot of accus to that location and the USB stick where the = data is written on has 64 GB, so i can run the experiment for more than = one week! :-)=20 For the first time i'm using two antennas. An active E field antenna = with a 1.5 m long steel wire as the capacitive probe. It is mounted on a = 10 m high pole. The E field preamp is supplied by a separate battery and = uses an isolation transformer with a low pass filter applied. The second antenna is my compact loop with 80 cm diameter and 84 turns. = It uses a low noise preamp (also supplied by a separate battery) using a = LT1028. This loop RX worked surprisingly well on 4470 Hz when beeing in = France last September. Hopefully it will pick up the signal. Unfortunately the E field antenna is not very high above the = sourrounding trees, so the sensitivity may be limited. Also the H field = antenna showed much more mains hum than expected in this location. So it = may be a bit questionable if the experiment will be successful. The long = transmissions will allow to stack carrier transmissions and/or EbNaut = transmissions though... Running 36 mA antenna current means an ERP of 10 nW on that frequency.=20 My transmission plan is: 30.JAN, 17 UTC: Carrier on 970.005 Hz 01.Feb, 17 UTC: Carrier on 970.0025 Hz 02.Feb, 17 UTC: EbNaut, 16K21A, 2 char, 100 sec, CRC22 (24 hours) 03.Feb, 17 UTC: EbNaut, 16K21A, 2 char, 100 sec, CRC22 (24 hours) 04.Feb, 17 UTC: EbNaut, 16K21A, 5 char, 80 sec, CRC17 (23:49:20) 05.Feb, 17 UTC: EbNaut, 16K21A, 5 char, 80 sec, CRC17 (23:49:20) Not sure if someone else can pick up the signal. Most likely not. But = new components to rise the voltage to 20 kV in a next experiment are = already in preparation... 73, Stefan =20 ------=_NextPart_000_02D5_01D3D329.35084290 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable

Hello Stefan,

 

Congratulations on your 40.5 km 970 Hz record with loop-only = receiver; and the successful preparation that = preceded.

 

Do you think that you might have also overcome a receiver = polarization challenge in the process?

 

With a surface TX loop to RX loop near field link I keep both loop = planes vertical (both loop axes horizontal), with the RX loop axis = pointing at the transmitter (RX loop plane facing the = transmitter).

With a surface TX loop to RX loop far field link I keep both loop = planes vertical (both loop axes horizontal), with the RX loop axis = pointing perpendicular to the transmitter (RX loop plane edge pointing = toward the transmitter).

With a TX vertical-antenna to RX loop far field link I keep the RX = loop axis pointing perpendicular to the transmitter (RX loop plane edge = pointing toward the transmitter).

 

I=E2=80=99m not sure what the polarization of your TX antenna would = be at 40.5 km (~ 1/8 wavelength, near the first of the two = near/far-boundary impedance intersections), or what the best RX loop = orientation would be for such TX near-field-boundary signal = polarization. Do you think that your RX loop was fairly well aligned for = the 970 Hz 1/8 wavelength polarization of your TX = signal?

 

Congratulations on another important and most interesting (970 Hz = near-far impedance-crossover point) record!

 

73,

 

Jim AA5BW =C2=A0=C2=A0

 

 

 

 

From: owner-rsgb_lf_group@blacksheep.org = [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of = DK7FC
Sent: Wednesday, April 11, 2018 9:13 = AM
To: rsgb_lf_group@blacksheep.org
Cc: Renato = Romero
Subject: Re: ULF: New experiment on 970 Hz 3/3 = summary

 

Hello ULF = friends,

Here is the summary of my recent portable experiment on = 970.005 Hz.
The goal of the experiment was to undoubtly = detect my own transmission in a distance of 40.5 km. The experiment took = about 8 days, starting 30.JAN.2018, 16:30 UTC. For the first 3 days, a = carrier was transmitted on 970.005 Hz, for 48 hours, and then 24 hours = on 970.0025 Hz. Afterwards, a 2 character EbNaut message was = transmitted, taking 24 hours exactly, two times repeated. And finally, a = 5 character message was transmitted, also taking 24 hours, two times = repeated.

This is the path ht= tp://k7fry.com/grid/?qth=3DJN49BK33UG&from=3Djn49ik00wd which = the 18 nW ERP signal had to cross.

Along with the other = experiments i've done during that time, it took nearly two months for me = to learn how to operate Paul's vlfrx tools and to do all the post = processing.
I had to determine:
-The best noise blanker settings, =
-The best filter shape, bandwidth and center frequency
-The = optimum hum filter parameter settings
-The phase between E field = (whip) and H field (loop)
-The best mixing coefficients (amplitude, = phase) between E and H
-The phase difference of the signal between = day and night
...all to maximise the SNR of the carrier peak and = Eb/N0 of the messages.

Unfortunately the E field was not usable = for most of the days. Either something got damaged on the front end JFET = or the shielding effect of sourrounding trees has been much higher than = expected. The performance of the 84 turn loop antenna having 0.8 m = diameter and a low noise preamp was fine, though not optimal since there = were AM broadcast signals audible during the sunrise and sunset (a = resonance on HF, resulting in an overloaded preamp at times?!).
So = all in all there were a lot of performace limiting = issues.

Anyway, the two character message was decoded without = much tweaking of blanker etc. settings. Based on these signals to = analyse, along with the carrier, it was possible to find the best = settings to even get a decode of the 5 character message in the end! The = carrier result and the 5 character message is H field only!
Here are = the results:
Spectrum peak of the 72 hour carrier = transmission, combined in one peak: http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/TR3_Endv= ersion.png
2 character message: http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/2ch970= Hz40km_E+H.png
5 character message: http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/5ch970Hz40= km.png

So let me conclude the experiment was a full success, = despite all the trouble and limitations i had. And it means that more = distance can be expected if the RX system is working as = intended!

This new distance record of 40.5 km on the 309 km band = is still in the near field for that wave! See http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/Na= hfeld%C3%BCbergang.png

These are the locations of all = experiments done on the 309 km band so far: http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/970Hz_bish= er.png

For the next experiment, i definitively plan to cross = the far field border ( > 49.3 km). The idea is to use about 3 dB more = power and a working RX system and a better location for the E field :-) = When doing it in the summer months, the 3 dB more power will be = compensated by QRN i fear.

A photo from the RX site in the snow: = http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/RX_site.jpg=
A photo showing the data recorder: http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/Raspi.jpg
= And the batteries afterwards: = http://www.iup.uni-heidelberg.de/schaefer_vlf/ULF/40km/Batt.jpg
73, Stefan

PS: Thanks to Paul Nicholson for the support in = learning how to use vlfrx tools!





Am 08.02.2018 = 13:44, schrieb DK7FC:

Hello dear = friends of the Ultra Low Frequencies,

Update:
There are a few = things to note so far:

I made a mistake in the calculation of the = ERP. It is not 10 nW but rather 18 nW.

All = transmissions seemed to go out as intended. The stream from the local = tree was interrupted almost daily due to lack of solar energy but at = least a few hours came through. From these few hours i got decodes of = each carrier transmissions. I also got decodes of all EbNaut messages. = So things went well from the TX site it seems.

The 36 mA = antenna current (12 kV antenna voltage) was running for 8 days = without a single interruption. The constructed resonating transformer = has done its job flawlessly.

Since i decided to take back the RX = equipment on the 7th of February, there was some more time for another = EbNaut message:
06.Feb, 17:30 UTC: EbNaut, 16K21A, 1 char, 90 sec, = CRC27 (21:12:00)

The experiment stopped at 15:45 UTC. BTW the = exact location was JN49BK33UG  = That is a distance of 40.5 km to the TX site. But so far there are no = decodes or traces, so no success so far.

The next good step is = that the whole RX equipment has still been in its place, nothing stolen, = nothing damaged. The Raspi was still running after 8 days. The Raspi was = supplied by two 12 V / 26 Ah lead gel accus. They were standing in the = snow and discharged to 11.8 V! The two accus for the preamps of the loop = and vertical were still above 12.3 V. So that was all fine = too!

Now the stuff is sorted, cleaned and the accus are charging = and warming up again here.

I just started the Raspi and checked = the data on the 64 GB USB stick. This looks good and promising, see = attachment. And it looks like there were no timing breaks of the GPS = module.
For the first time i run the recording using vlfrx tooly by = Paul and the octo soundcard. Also it is the first set of data i have = available to build a cardioid antenna by software... Exciting stuff. =

The recording process by vlfrx tools saves to a new file each = day.
Here the files are 7.8 GB large:  2 channels * 24000 = samples/(channel*second) * 16 bit/sample * 3600 seconds/hour * 24 = hours/day * 1/8 Byte/bit * 1/1024 kByte/Byte * 1/1024 MBity/kByte * = 1/1024 GByte/MByte =3D  7.72 GB/day 

Obviously the = recording process was stopped during the last night 03:58 UTC because = the USB stick capacity seems to be just 58 GB actually. The recording is = started/stopped by switching a switch which is connected to one of the = GPIO pins. This is necessary because in the field there is no monitor = and no keyboard of course. At start-up, a scripts is executed which = checks the logic level of the pin where the switch is connected... = During the recording process, a loop is running within this script which = periodically checks the remaining available
space of the data = carrier. As soon as the remaining space becomes less than 100 kB, the = recording process is stopped. This ensures that there is still enough = space to save the log files which are written at the end of the = recording process. It also ensures that there are no crashes and = unwanted data loss, broken files etc...

In a few days i can = report about the results, so stay tuned...

73, = Stefan




Am 31.01.2018 14:30, schrieb DK7FC: =

Hi = all,

Since yesterday, ~ 17 UTC, i'm running a new portable = experiment on 970 Hz, or the 309 km band. The receiver site is somewhere = in the forest in JN49BK, a distance = of  40 km to the TX site.

I carried a lot of accus to that = location and the USB stick where the data is written on has 64 GB, so i = can run the experiment for more than one week! :-)

For the first = time i'm using two antennas. An active E field antenna with a 1.5 m long = steel wire as the capacitive probe. It is mounted on a 10 m high pole. = The E field preamp is supplied by a separate battery and uses an = isolation transformer with a low pass filter applied.
The second = antenna is my compact loop with 80 cm diameter and 84 turns. It uses a = low noise preamp (also supplied by a separate battery) using a LT1028. = This loop RX worked surprisingly well on 4470 Hz when beeing in France = last September. Hopefully it will pick up the signal.
Unfortunately = the E field antenna is not very high above the sourrounding trees, so = the sensitivity may be limited. Also the H field antenna showed much = more mains hum than expected in this location. So it may be a bit = questionable if the experiment will be successful. The long = transmissions will allow to stack carrier transmissions and/or EbNaut = transmissions though...

Running 36 mA antenna current means an = ERP of 10 nW on that frequency.
My transmission plan = is:
30.JAN, 17 UTC: Carrier on 970.005 Hz
01.Feb, 17 UTC: Carrier = on 970.0025 Hz
02.Feb, 17 UTC: EbNaut, 16K21A, 2 char, 100 sec, CRC22 = (24 hours)
03.Feb, 17 UTC: EbNaut, 16K21A, 2 char, 100 sec, CRC22 (24 = hours)
04.Feb, 17 UTC: EbNaut, 16K21A, 5 char, 80 sec, CRC17 = (23:49:20)
05.Feb, 17 UTC: EbNaut, 16K21A, 5 char, 80 sec, CRC17 = (23:49:20)

Not sure if someone else can pick up the signal. Most = likely not. But new components to rise the voltage to 20 kV in a next = experiment are already in preparation...

73, = Stefan

 

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