On 6/15/23 4:38 AM, Bryan Curl wrote:
Hi Jim,
How do you do that?
[
"But it's good to check (and hey, you could use the NanoVNA to measure it)."
]
Bryan, n0luf
Measuring switch isolation.
Let's say your switch has a common, and 4 switched outputs A,B,C,D
Hook the VNA up to Ch0 to A and Ch1 to B, put a load on Common, set the switch to A, and measure the S21. Or select neither, or C, and measure S21 (which should be lower)
You could also hook the VNA Ch0 to Common, Ch1 to output A, then select A (S21 will be the loss/phase shift through the switch) then select one of the others (S21 is the common to unswitched port leakage).
If you want to be complete on this kind of thing (or small leakages perturb the system) then you may want to put termination on unused ports and see if it makes a difference.
