Thnx, Alan.
I saw someone introduced 75Ohm load side's VSWR with 50Ohm matched VSWR measurement gear
- Easy formular, but it does not suitable for measure sourceZ I think.
Also I already thought coupler that has reference load connectors(4 port with 1:1 balun)
- Coupler input port circuit was already 50 Ohm matched( If unknown sourceZ not matched 50 Ohm, power will reflected before reaching coupler circuit I think ), I already know my loadZ(antenna) through 50 Ohm calibrated VNA.
COLD method I will try with shorter than 1/10F cable lengths :-)
I wish to know further more knowledge about 10W powered sourceZ proper/right measurment method.
