Hi Jim, Paul,
Am 07.12.2017 21:04, schrieb [email protected]:
Receiver is at 38.915547, -77.124948
Or FM18KV59AS :-)
As Paul suggested, i would agree that recording the audio is the best
you can do. Later you can try to create different spectrograms or try
to get an EbNaut decode. Record in stereo, with the PPS pulses on the
other channel. If you are using NMEA+PPS this would be ideal. Otherwise
you can note the start time and set it manually later.
My signal is to weak to get a trace on a spectrogram in that distance
but you could try to get a single spectrum peak by using a rectangular
window (FFT register card) and select a FFT window time equal to the
common night time of 8.5 hours. Then start that SpecLab instance at 22
UTC. After 8.5 hours you will get the first spectrum. With some luck
you can see the strongest peak right on 17470.1000 Hz.
8 hours raw data ~ 11 GB if I calculated correctly.
8 hours * 3600 sec/hour * 16 bit/sample * 48000 samples/sec * 2
channels = 44236800000 bit = 5529600000 byte = 5.15 GB Maybe you are
referring to a sample rate of 96 kS/s, then your ~11 GB is correct.
I'm not sure but i think i remember that i learned that 1 kB = 1024 B,
not 1000 B. But i am not sure.
OK to use raw data from SpecLab running in Windows?
Generating wav files (larger than 4 GB) works very well on SpecLab.
No need for EbNaut?
You can do that later.
Paul wrote:
I'm able to log into Mike's VLF computer to extract raw signal.
I already wondered how you watch for a 17470 Hz signal from a 32 kS/s
vorbis stream :-)
Just for fun i'm watching Alpha F1 (11904.7619 Hz) from that stream in
VA. It has 23 dB SNR in 424 uHz!
73, Stefan
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