Re: R: Re: VLF: EbNaut message over 2877 km, DK7FC to RC4HAA

[Markus Vester <markusvester@aol.com>]

Hi Stefan,

your recent messages were also successfully decoded at DF6NM (E-field) and DL0AO (west cardioid):

date msg df6nm dl0ao
Nov.           dB     dB
5-6     R    13.2  12.0
6-7    73    10.4   9.4
7-8    xxx    1.6    7.5
8-9    xxx  10.9    7.4
9-10   xx   11.9    8.1

Note that these carrier Eb/N0 results are probably 1.5 dB too low, due to our short 8.9 hour recordings. Today I have changed the FFT resolution on our grabbers from 31.4 to 20.93 uHz, so that SpecLab data exports will now be covering up to 13.23 hours.

Best 73,
Markus (DF6NM)



-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Do, 9. Nov 2017 18:36
Betreff: Re: R: Re: VLF: EbNaut message over 2877 km, DK7FC to RC4HAA

Thanks Paul, good to see.
I tried various time and frequency offsets for the wav file from last night and for the stacked file from the last two nights. No result.
Now i started two SpecLab instances on the RX site, one is using PPS+NTP, the other one DHO38. During the transmision time, DHO38 has a good strength and no terminator is passing, so maybe it will give better results, at least it will be interesting to compare.
Since i want to avoid false decodes, i changed the parameters and will try 2 characters again. Tonite:

f = 8270.1000 Hz
Start time: 09.November.2017  16:00:00 UTC
Symbol period: 60 s
Characters: 2
CRC bits: 15
Coding 16K21A
Duration: 12:32
Antenna current: 620 mA

73, Stefan


Am 09.11.2017 17:23, schrieb Paul Nicholson:

Stefan wrote:

> f = 8270.1000 Hz
> Start time: 07.November.2017  16:00:00 UTC
> Symbol period: 60 s
> Characters: 3
> CRC bits: 9
> Coding 16K21A
> Duration: 12:32

> Paul, did you copy my message from last night and the night
> before?

Yes, a strong signal here and perfect decode of the 3 chars:

            H-field           E-field             E+H field
 7th/8th  10.5 dB 99.8 deg   9.0 dB 107.3 deg   12.5 dB 103.3 deg
 8th/9th  14.1 dB 88.3 deg  12.5 dB  93.8 deg   17.3 dB  90.9 deg

> I am getting no decode at RC4HAA, even when stacking both nights.

Signal phase repeated fine both nights.  Given the S/N of your 2 char
success, you would be very lucky to do 3 chars in one night, but two
nights ought to do it.

--
Paul Nicholson
--