Hi Roger
You are right, i tested a 4.63 K Ohm serial resitor S21 gives me 5.35 Khom +15.6% error but regular static value across the 30Mhz span , S11 shunt gives me a very irregular values across the 30Mhz span , thats mean if we can calibrate better S21 resistor function it will give better accuracy measurements for hight values > 1K Ohm , I dont Know if there is a trick for this possible S21 compensation ?
see illustrations below
73's Nizar .
