Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, HTML_MESSAGE,RCVD_IN_DNSWL_MED,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: EATSERVER: mailn 1166; 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+deb8u1) with ESMTP id v23JLa7M029252 for ; Fri, 3 Mar 2017 20:21:37 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1cjshw-0008Px-1i for rs_out_1@blacksheep.org; Fri, 03 Mar 2017 19:17:40 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1cjshv-0008Po-4A for rsgb_lf_group@blacksheep.org; Fri, 03 Mar 2017 19:17:39 +0000 Received: from mout02.posteo.de ([185.67.36.66]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1cjshs-0000Oi-6M for rsgb_lf_group@blacksheep.org; Fri, 03 Mar 2017 19:17:38 +0000 Received: from submission (posteo.de [89.146.220.130]) by mout02.posteo.de (Postfix) with ESMTPS id DA71F20864 for ; Fri, 3 Mar 2017 20:17:33 +0100 (CET) Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 3vZf8F3WRkzytZ for ; Fri, 3 Mar 2017 20:17:33 +0100 (CET) Message-ID: <58B9C14D.5090403@posteo.de> Date: Fri, 03 Mar 2017 20:17:33 +0100 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: <15a944b24fd-44c1-9a00@webprd-m71.mail.aol.com> In-Reply-To: <15a944b24fd-44c1-9a00@webprd-m71.mail.aol.com> X-Scan-Signature: 29f1b43ee9e13e220716185d38bfb88c Subject: Re: VLF: Tonite... Content-Type: multipart/alternative; boundary="------------030606090601090800000707" 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: 10770 This is a multi-part message in MIME format. --------------030606090601090800000707 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Thanks Markus, Jacek and Eddie for the decodes. I'm planning a new message for tonite but still need some time to build up a new PC into the VLF TX system. The old one has 512 MB RAM, the new one has 2 GB which should make a real difference regarding soundcard glitches. Additionally i'm moving from PPS+NTP to PPS+NMEA. Announcement follows... 73, Stefan Am 03.03.2017 14:10, schrieb Markus Vester: > Good decode here as well. > > This transmission came just in time for me to test a different setup, > using samplerate lock to DCF77 rather than 1pps. I'm using a cheap > Delock USB sound dongle with VIA VT1630A chipset, which happens to > have only moderate antialias filtering. With 48 kHz samplerate, DCF77 > can be picked up in the 4th Nyqist band with only about 30 dB > attenuation. SpecLab's samplerate detector initially warns about the > too-low samplerate, but anyway processes the subsampled reference > correctly. At my distance from DCF77 (160 km), there is a bit of > nighttime phase variation, but fortunately this is reduced by almost > an order of magnitude when scaling from 77.5 to 8.27 kHz. > > After having decoded Stefan's message, I undid the PSK modulation and > plotted the received phase in 10 minute averages. There seems to be > some minor long-term phase drift, but apparently no phase-jumps from > dropouts have occurred. > > The same trick could probably also be used with other time signals, > e.g. 60, 66.667, 162 or 198 kHz. With appropriate filtering, it is > even possible to receive 137 kHz directly by subsampling. This might > be a useful way to steer the phase of an LF EbNaut transmitter by > GPS-phaselock, removing the need for an accurate local oscillator. > > Best 73, > Markus (DF6NM) > > > ebnaut-rx V0.5 > input file 03030123a.wav > sample rate 0.514405 per second > rx frequency 8270 > file start time 2017-03-02 20:58:21.300 > polynomial 16K21A > crc size 28 > number of chars 2 > block size 40 > symbol period 30.000 > number of symbols 960 > list length 200000 > start offset 407.000 > freq offset 0.100000 > cores 2 > skipped 406.294730 seconds to start > initial reference phase 40.0 > --------------------------------------------- > found XX > list rank 0 > reference phase 180 180 180 180 > carrier RMS 2.675e+004 noise RMS 1.578e+003 > carrier S/N 24.58 dB in 34.7 uHz > carrier Es/N0 -5.24 dB > carrier Eb/N0 14.01 dB > info bit period 2526.32 seconds > symbol error rate 192/960 = 20.000 % > Es/N0 from symbol errors -4.5 dB > Eb/N0 from symbol errors 14.8 dB > Shannon capacity 45.3 bits/hour > Shannon efficiency 3.1 % > symbols file 03030123a-symbols.csv > elapsed 10 seconds > --------------------------------------------- > found XX > list rank 0 > reference phase 150 150 180 180 > carrier RMS 2.672e+004 noise RMS 1.578e+003 > carrier S/N 24.57 dB in 34.7 uHz > carrier Es/N0 -5.25 dB > carrier Eb/N0 14.00 dB > info bit period 2526.32 seconds > symbol error rate 186/960 = 19.375 % > Es/N0 from symbol errors -4.2 dB > Eb/N0 from symbol errors 15.1 dB > Shannon capacity 45.2 bits/hour > Shannon efficiency 3.2 % > symbols file 03030123a-symbols.csv > elapsed 126 seconds > > > > -----Ursprüngliche Mitteilung----- > Von: DK7FC > An: rsgb_lf_group > Verschickt: Do, 2. Mrz 2017 22:15 > Betreff: VLF: Tonite... > > Hi all, > > It's time for a new EbNaut transmission. Another attempt to get a > decode from IK0VVE or IZ7SLZ and of course also for anyone else who is > interested :-) > > *f = 8270.100000 Hz > Start time: Thursday 02.Mar.2017 21:05:00 UTC (already running!) > Symbol period: 30 s > Characters: 2 > CRC bits: 28 > Coding 16K21A > Duration: 8h, 0m, 0s > Antenna current: 700 mA > > * If no decode appears, then it may help to repeat the process and > increase the list length to very large values, like 2000000. > > 73, Stefan --------------030606090601090800000707 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit Thanks Markus, Jacek and Eddie for the decodes.

I'm planning a new message for tonite but still need some time to build up a new PC into the VLF TX system. The old one has 512 MB RAM, the new one has 2 GB which should make a real difference regarding soundcard glitches. Additionally i'm moving from PPS+NTP to PPS+NMEA.

Announcement follows...

73, Stefan


Am 03.03.2017 14:10, schrieb Markus Vester:
Good decode here as well.

This transmission came just in time for me to test a different setup, using samplerate lock to DCF77 rather than 1pps. I'm using a cheap Delock USB sound dongle with VIA VT1630A chipset, which happens to have only moderate antialias filtering. With 48 kHz samplerate, DCF77 can be picked up in the 4th Nyqist band with only about 30 dB attenuation. SpecLab's samplerate detector initially warns about the too-low samplerate, but anyway processes the subsampled reference correctly. At my distance from DCF77 (160 km), there is a bit of nighttime phase variation, but fortunately this is reduced by almost an order of magnitude when scaling from 77.5 to 8.27 kHz.

After having decoded Stefan's message, I undid the PSK modulation and plotted the received phase in 10 minute averages. There seems to be some minor long-term phase drift, but apparently no phase-jumps from dropouts have occurred.

The same trick could probably also be used with other time signals, e.g. 60, 66.667, 162 or 198 kHz. With appropriate filtering, it is even possible to receive 137 kHz directly by subsampling. This might be a useful way to steer the phase of an LF EbNaut transmitter by GPS-phaselock, removing the need for an accurate local oscillator.

Best 73,
Markus (DF6NM)
 

ebnaut-rx V0.5
input file 03030123a.wav
sample rate 0.514405 per second
rx frequency 8270
file start time 2017-03-02 20:58:21.300
polynomial 16K21A
crc size 28
number of chars 2
block size 40
symbol period 30.000
number of symbols 960
list length 200000
start offset 407.000
freq offset 0.100000
cores 2
skipped 406.294730 seconds to start
initial reference phase 40.0
---------------------------------------------
found XX
list rank 0
reference phase  180  180  180  180
carrier RMS 2.675e+004 noise RMS 1.578e+003
carrier S/N 24.58 dB in 34.7 uHz
carrier Es/N0 -5.24 dB
carrier Eb/N0 14.01 dB
info bit period 2526.32 seconds
symbol error rate 192/960 = 20.000 %
Es/N0 from symbol errors -4.5 dB
Eb/N0 from symbol errors 14.8 dB
Shannon capacity 45.3 bits/hour
Shannon efficiency 3.1 %
symbols file 03030123a-symbols.csv
elapsed 10 seconds
---------------------------------------------
found XX
list rank 0
reference phase  150  150  180  180
carrier RMS 2.672e+004 noise RMS 1.578e+003
carrier S/N 24.57 dB in 34.7 uHz
carrier Es/N0 -5.25 dB
carrier Eb/N0 14.00 dB
info bit period 2526.32 seconds
symbol error rate 186/960 = 19.375 %
Es/N0 from symbol errors -4.2 dB
Eb/N0 from symbol errors 15.1 dB
Shannon capacity 45.2 bits/hour
Shannon efficiency 3.2 %
symbols file 03030123a-symbols.csv
elapsed 126 seconds



-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Do, 2. Mrz 2017 22:15
Betreff: VLF: Tonite...

Hi all,

It's time for a new EbNaut transmission. Another attempt to get a decode from IK0VVE or IZ7SLZ and of course also for anyone else who is interested :-)

f = 8270.100000 Hz
Start time: Thursday 02.Mar.2017   21:05:00 UTC (already running!)
Symbol period: 30 s
Characters: 2
CRC bits: 28
Coding 16K21A
Duration: 8h, 0m, 0s
Antenna current: 700 mA

 If no decode appears, then it may help to repeat the process and increase the list length to very large values, like 2000000.

73, Stefan
--------------030606090601090800000707--