Coax is, of course, not identical to paired cable, but using a low end of 50 kHz makes me wonder whether the velocity might be lower than the published high frequency value sufficiently to skew the results a bit. Maybe using a higher frequency low end would be better. I don't know enough about the characteristics of coax at low frequencies to be sure, just raising a caution here.
BEFORE I get "analyzing" the TDR (nanoVNASaver) source code , allow me to take another stab at this .
In basic steps - how do I setup to measure length of KNOWN type of coaxial cable using TDR - in nanoVNASaver ?
Assuming that TDR uses specific frequency to perform the task (?)
Setup nanoVNASaver sweep starting frequency
setup nanoVNASaver sweep ending frequency
run sweep
open / push "Time Domain Reflectometry..." in TDR "window"
observe TDR graph and "ESTIMATED cable length:"
change / verify the cable type (!) - changes VF according to cable type
optionally fiddle with TDR graph X-axis whose parameters are in "meters" , not in nS.
Length is measured in meters (duh) but TDR calculates using "time" and reflection time is related to frequency used.
Does all this makes some sense or am I missing IMPORTANT part / option / parameter?
All this using nanoVNASaver - no other tool , for time being...
