I have tried unsuccessfully to import the locally installed library with the import function feature of the equation editor.The other local libraries import with no issues which leads me to believe my copy of bestfit.dll may be corrupt.
Bestfit.dll is installed when you install the PNA firmware. if you think your current copy is corrupt somehow, you can uninstall and then reinstall the firmware. you can download new firmware installation packages for various PNA models here.
it is in a funny place: C:\Program Files (x86)\Keysight\Network Analyzer\UserFunctions
On the B version. replace KEysight with Agilent for the A version.
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