SWR meter how it works?

[coper1]

Could someone explain how these work tjis circuits?





I know this somehow compares forvard current from TX to load with reflected wave reflected from the load.
however, I do not know how, and especially how to calculate results
your advice?
is somewhere in detail described the circuits?

 

[E-design]

Look at this YouTube video.
https://www.youtube.com/watch?v=byF1FLdbUiA

 

[coper1]

Thanks for this interesting video, but it comes to me rather a version with center taped current transformer
I make this picture.
It is this true or am I wrong

 

[carpenter]

See on Breune coupler or Breune meter for example
eventually Stockton coupler or meter.