Re: LF: SL settings for EbNaut FFT recording ?

[Markus Vester <markusvester@aol.com>]

Hi Luis,

the attached usr is similar to what I'm using here.

Notes:

- The data files (named MMDDhhmm.txt) will be written every hour into a folder "data8H". You will first have to create this folder in SpecLab's main folder.
- The duration of one FFT (and one data file content) is 1/31uHz ~ 8.9 hours. After startup, don't be impatient because the first aquisition will take 8.9 hours. Thereafter a fresh one will appear every hour, (i.e. 7.9 hours overlap). 
- The FFT center frequency has been set to 8270.000, so you will need to enter the 0.1 Hz frequency offset later into the EbNaut decoder.
- The samplerate sync has been set to 1pps without NMEA. This means that you have to keep your PC clock within +-0.5 s. Alternatively, you could use a resistor to inject serial NMEA data into the right channel, and enable it in the  SR detector menu.  
- After first startup, you will need to let the SR detector calibrate the true samplerate of your soundcard, and enter that into the correction table. You can also use the ">>" button in the SR detector window.
- Take a note of the calibrated samplerate, because it will also be needed for the sr.txt file, which will be used by the ebnaut_ifft3a utility.
- I would recommend to enable "use file buffer" under Options-Memory (size e.g. 120 MB) so that display contents will be restored after a restart.

Good luck!
Markus

-----Ursprüngliche Mitteilung----- maintain
Von: VIGILANT Luis Fernández <luis@vigilant.es>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: So, 30. Apr 2017 10:31
Betreff: LF: SL settings for EbNaut FFT recording ?

Hi EbNauters

Finally running here an E-field probe connected to the soundcard and 1pps disciplinning

VLF signals are weak but I can see 11.904 Alpha at 374uHz stable and right on frequency

What I still need to clear out is how to configure SL to correctly export the FFT bins in a file

at the right time and duration for a planned transmission

Can you give me an example of what would be the config needed for Stefan's planned transmission ?

f = 8270.100000 Hz
Start time: 30.Apr.2017   07:00:00 UTC
Symbol period: 15 s
Characters: 12
CRC bits: 15
Coding 16K21A
Duration: 7h, 8min
Antenna current: 600 mA

73 de Luis

EA5DOM

vlf_EbNaut_31uHz_usr.zip
Description: Zip compressed data