[TowerTalk] hardline sweep - strange result

John Keating john.keating at outlook.com
Sat Sep 20 20:00:47 EDT 2025


Jim and Dan, thanks for the comments and suggestions. I ran Zplots TL 
params on data from my TAPR VNA and saw no unusual results. I rescanned 
the cable with the RigExpert but viewed the data on AntScope2 software 
which showed the step response reflection coefficient stayed at zero. 
AntScope has a specific cable parameter selection for FSJ4 cable, while 
the RigExpert unit itself does not (it only permits selection of a 
limited set of cables and velocity factors). I suspect the anomaly is 
due to the algorithm or parameters stored in the unit being different 
from those in the PC software. I sent an inquiry to RigExpert but don't 
expect to hear back given the situation in Ukraine. Meanwhile I will 
proceed on the basis that the cable is in good condition.

73, John K7LY


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