Re: LF: VLF DK7FC > W1VD 8.27 kHz EbNaut more success!

[Markus Vester <markusvester@aol.com>]

Well there were a few occasions of unstacked single-night decodes from VO1NA at DL0AO, "S" on Dec 23/24, and "V" on Dec 28/29 and 29/30. We were not successful with the daytime transmissions.

The TX power ratio may be a bit less than 16 dB. I assume that both Joe and myself achieve around 10 uW radiated power ("EMRP"), whereas Stefan usually states "ERP" with reference to a dipole which is 1.83 times higher. Based on various receive comparisons, my best guess would be that DK7FC's antenna has around 16 m effective height, giving 150 uW EMRP (275 mW ERP), or about 12 dB more power for E-W. So considering other factors like receive antennas, results are probably consistent with a 9 dB nonreciprocity.

Best 73,
Markus

-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Mo, 26. Feb 2018 15:36
Betreff: Re: LF: VLF DK7FC > W1VD 8.27 kHz EbNaut more success!

Hi Jim,

Yes but the messages from VO1NA took much longer to decode at limilar distances. I don't know exactly, i think it was something between 4...6 days to produce a decode at DL0AO ?
But that was with a longer TX period and in the deep winter. Not to think about the local noise differences and antenna directivity... Jay uses a pure omni-directional E field probe whereas DL0AO used a software combined cardioid antenna pointing to EW exactly.
In the end there are some uncertainties which makes it hard to determine the actual E-W/W-E attenuation. But it looks like something between 10...20 dB is a good estimate.

Depending on the time it needs to produce a lucky 5 character decode at W1VD, i will soon move to 17.47 kHz again to start experimenting with Edgar in VK7, just a path of 16805 km (http://k7fry.com/grid/?qth=QE37PD35&from=jn49ik00wd).
Then at night we can try to transfer a message to W1VD at 17.47 kHz to see the difference of the attenuation. The old graphs suggest a big difference but i bet it is not much, maybe 6 dB.

73, Stefan



Am 26.02.2018 15:15, schrieb hvanesce@comcast.net:

Stefan,

 

Thank you for the reminder. All of the permeable-core selection/placement and winding improvements come to mind when you mention that number.

 

Correcting the sentence below: “(ERP ratio 16dB)…offset a nominal E-W/W-E attenuation ratio (9 dB EW/WE ratio for 6Mm path) by 7dB.

 

Excellent ERP, and glad that Markus pointed out the quantitative consistency of same-month E-W and W-E link results with non-reciprocity at 8270 Hz.

 

73,

 

Jim AA5BW

 

    

 

From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of DK7FC
Sent: Monday, February 26, 2018 6:34 AM
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: VLF DK7FC > W1VD 8.27 kHz EbNaut more success!

 

Thanks Jim,

ERP is 400 uW. Often discussed but my statement here :-)

73, Stefan

Am 26.02.2018 04:31, schrieb hvanesce@comcast.net:

Congratulations Jay and Stefan, and thanks Markus for the perspectives and reference points. I have a rough recollection of Stefan’s estimated ERP, which would seem to slightly more than offset a nominal E-W/W-E attenuation ratio, making Markus’ two propagation observations particularly interesting, as is the Forest question.

 

Fine work Stefan and Jay.

 

73,

 

Jim AA5BW   

 

From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Markus Vester
Sent: Sunday, February 25, 2018 2:25 PM
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: VLF DK7FC > W1VD 8.27 kHz EbNaut more success!

 

Hi Jay, Stefan,

really good work, truly amazing!

Noticing that Stefan hadn't sent another repeat last night 24/25th, I wondered whether the experiment might have already been concluded successfully - yes it had ;-)

Considering that Joe has been making the TA W-E path with only 10 uW, in retrospective it seems not so surprising that Stefan's much stronger signal managed to overcome the E-W nonreciprocity. On the other hand, when Uwe had sent a very long carrier in March 2014, no conclusive trace was ever detected in Virginia. Now I wonder whether Stefan's recent transmission has also been picked up in Forest?

All the best,
Markus (DF6NM)  


-----Ursprüngliche Mitteilung-----
Von: jrusgrove <jrusgrove@comcast.net>
An: (rsgb_lf_group@blacksheep.org) <rsgb_lf_group@blacksheep.org>
Verschickt: So, 25. Feb 2018 19:26
Betreff: LF: VLF DK7FC > W1VD 8.27 kHz EbNaut more success!

Stefans transmission:

 

f = 8270.1000 Hz
Start time: 19.FEB.2018  22:30:00 UTC (daily)
Symbol period: 30 s
Characters: 2
CRC bits: 22
Coding 16K21A
Duration: 07:12 [hh:mm]
Antenna current: 700 mA

 

After a successful one character reception earlier in the week, we can now report the successful reception of a 2 character message. Stacking of 3  transmissions was required (0221, 0222 and 0223). There is also a 0224 file but it has timing issues and may or may not be usable.

 

ebnaut-rx V0.8
input file C:\EbNaut\DK7FC\sum212223.wav
sample rate 0.457240 per second
rx frequency 8270
file start time 2018-02-22 22:21:17.790
polynomial 16K21A
crc size 22
number of chars 2
block size 34
symbol period 30.000
number of symbols 864
start offset 537.000
freq offset 0.100000
cores 2
list length 500000
skipped 538.011261 seconds to start
initial reference phase 30.6
---------------------------------------------
found DX
list rank 48426
reference phase 150,150,150,150
carrier S/N 11.04 dB in 38.6 uHz, -33.10 dB in 1Hz, -67.08 dB in 2.5kHz
carrier Es/N0 -18.33 dB
carrier Eb/N0 0.47 dB
info bit period 2273.68 seconds
symbol error rate 373/864 = 43.171 %
Es/N0 from symbol errors -18.2 dB
Eb/N0 from symbol errors 0.6 dB
Shannon capacity 2.5 bits/hour
Shannon efficiency 62.7 %
symbols file C:\EbNaut\DK7FC\sum212223-symbols.csv
elapsed 52 seconds
---------------------------------------------
found DX
list rank 17074
reference phase 120,150,120,150
carrier S/N 11.19 dB in 38.6 uHz, -32.94 dB in 1Hz, -66.92 dB in 2.5kHz
carrier Es/N0 -18.17 dB
carrier Eb/N0 0.62 dB
info bit period 2273.68 seconds
symbol error rate 374/864 = 43.287 %
Es/N0 from symbol errors -18.4 dB
Eb/N0 from symbol errors 0.4 dB
Shannon capacity 2.6 bits/hour
Shannon efficiency 60.5 %
symbols file C:\EbNaut\DK7FC\sum212223-symbols.csv
elapsed 383 seconds

Jay W1VD  WD2XNS  WE2XGR/2