Hi Rudi,
The MATLAB T-check script is part of a package of scripts written by Dick Benson, W1QG, and downloadable from the Matlab Central:
Please note that it requires MATLAB's "RF Toolbox", so I do not know if it is compatible with Octave. Give it a try, maybe it will work.
And note that the T-check script works with an S2P file.
Best of luck!
- Jeff, k6jca
