On 1/2/18 9:58 AM, Jim Brown wrote:
Hewlett Packard''s app note on this topic is well known, and my own
attempts at measuring high values of Z using S11 resulted in large errors.
73, Jim
On 1/2/2018 5:28 AM, Wes Stewart wrote:
You keep saying that and I keep directing you to Kurt's paper that
shows this is incorrect.
http://hamcom.dk/VNWA/How%20to%20measure%20very%20high%20impedances-Deutsch%20DG3OK.pdf
if you're measuring 500 ohms (10:1) a 1% error in the voltage reflection
coefficient is a 5% error in the resistance. 1% is 0.09 dB
It gets worse:
950 ohms is 10.4%
2450 ohms is 32.2%
4.95k ohms you get 100% error if the VNA is 0.1dB (which is a typical
number)
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|