RE: VLF: TA east to west?

[<hvanesce@comcast.net>]

Stefan and Paul,

 

All up and running per details of your suggestions, thank you.

 

Started 192 ksps .wav file at 1500 UT.

 

Spectrogram integration time ~ 12 hours, centered at 17470.1000 Hz

 

Antenna bearing optimized.

 

73,

 

Jim AA5BW

 

 

 

From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of DK7FC
Sent: Thursday, December 7, 2017 3:59 PM
To: rsgb_lf_group@blacksheep.org
Subject: Re: VLF: TA east to west?

 

Hi Jim, Paul,

Am 07.12.2017 21:04, schrieb hvanesce@comcast.net:

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