This is a serious mathematical topic, so if you haven't spent a LOT of time doing time series analysis, please stay quiet.
It might be just one of those cultural differences, but telling people to stay quiet on a forum is not polite.
You can always specify you are interested only in answers coming from people with a specific level of expertise, but you can not tell anybody to shut up. Also, all math is serious, but I don't want to go into rant mode.
Judging from the fact that you are talking about SA, VNA and SDR in the same subject, i guess we are using the same terms, like SA, to name different instruments.
Here is the block diagram of an SA:
http://www.rfwireless-world.com/Terminology/spectrum-analyzer-basics.htmlWith that architecture, you can not have a fully functional VNA.
Also, you want to use the instrument in some geologic mesurements. What exactly do we need to measure? You must specify that, unless you are asking the questions in a geology forum.
Without that info:
- can we just use some software instead of expensive seismology equipment? No. Whenever some instrument is expensive, there are reasons.
- can an SA be a VNA? No.
- can an SDR architecture be used to do measurements like a VNA? Yes.
- can a limeSDR be used in geology? I don't know what we need to measure, and with what precision or accuracy.