I did the experiment on the F-antenna and on the Whip Antenna again.
Here are the results:
The data for the F antenna didn’t show the separation that we were looking for. However there was a nice separation between .5 and 1 m, which we could consider in the future.
This time, the whip antenna didn’t show inversion between 5. and 1 m. The separation isn’t the best to make a single cut off value, but it’s still pretty good.