vlfrx-tools - interesting program, also might be useful for eclipse

[cdev]

VLFRX-Tools ( http://abelian.org/vlfrx-tools/ )
looks like a program that might have all sorts of useful features, its primarily a VLF receiver that works with a number of input options (including rtlsdr, probably in direct sampling mode..as well as with a sound card - direct input.. have to check that out tonight) It also it has some timing related features it seems.

http://abelian.org/vlfrx-tools/notes.html

There are specific instructions for setting up the input RC network so that the proper instant is registered as the start of the PPS pulse.

Looks interesting. Wonder if these plots were made with it?

Ive never seen pps run into a sound card but its possible it could work..

Its apparently important to use an rc network on the input, and how its set up is important for accuracy.
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RC Values
Suitable R and C values for pulse shaping can be estimated as follows. Given
Rin = input resistance of the sound card, ohms;
Vf = full scale input amplitude of the soundcard, volts;
Vp = pulse amplitude out of the GPS, volts;
Pw = pulse width, seconds
then
R = Rin * (1.25 * Vp/Vf - 1)
C = Pw/(pi * Rin * (1 - 0.8 * Vf/Vp))