but is there any useful
information?

most people don't use them
because a simple swr meter is adequate for testing
most antenna./feedline
combinations in use by amateurs.

===============================

Following a query, Guru's feel an urgent desire to display their knowledge
about S-parameters, Time domain reflectometers, Circulators, and High power
UHF TV transmitters.

As a consequence, the unfortunate original questioner, with his solitary 1.8
to 30 MHz SWR meter, is entirely forgotten about and remains suspended in
mid-air.
----
Reg, G4FGQ