Reflection coefficient bridge question

[neazoi]

Hello, I have made and documented (well I think) the construction of a reflection coefficient bridge **broken link removed**
There is a question that I would like to figure out

This bridge has been designed for matshing 50R systems.
What is I want to match say a system of 300R?

I am thinking of doing it this way:
1. connect a reference 50R load to the reference port.
2. connect a reference 300R resistor to the measurement port.
3. read the meter value and write it down, or zero the meter (if the meter has this capability)
4. remove the 300R resistor and connect in place the 300R system to match.
5. A well matched 300R system would yeld the same value in the meter like the reference 300R resistor.

Are my thoughts correct?
If this is true, then this bridge could be used to match non-50R systems as well.

 

[chuckey]

Really the through line should be constructed to the system impedance - I could not see any dimensions for the hole in the block of Ali. Like wise the 2 X 100 ohms should be changed to 2 X 600 ohms. What connector are you using for your 300 ohm line?, and cable ?
But you are right, calibrating it with different value resistors will give you a comparative value.
Frank

 

[neazoi]

Really the through line should be constructed to the system impedance - I could not see any dimensions for the hole in the block of Ali. Like wise the 2 X 100 ohms should be changed to 2 X 600 ohms. What connector are you using for your 300 ohm line?, and cable ?
But you are right, calibrating it with different value resistors will give you a comparative value.
Frank

Ok, so as far as I understand my proposed way to match a 300R (or other) impedance is correct.

Well the connectors are 50R SMA but the amount of imballance will be the same (for the same frequency) regardless of the 300R load or the unknown device which needs to be matched to 300R. So basically, if one nulls the meter on the 300R reference load, he will see the same null when the device to be tested is matched to 300R.

I hope I am getting this correct?