VNA2180 S21 MEASURMENT

[missouri]

Doing some port-B S21 measurements with my VNA2180 on a 180-degree phase shift transformer.....The '2180 ports A & B are properly calibrated and the phase "limits" are set to indicate +-200 degrees. The frequency range is the 40m band.

The '2180 is indicating a phase shift of +176.4 degrees, when I know that it should be a little more than a *negative* 180 degrees, i.e. -183.6.

So, why would there be such a huge difference?

Thanks,
Charlie

[missouri]

Whoopsy! I shouldn't do any posting late at night....belay my last post...gotta figure this out before posting again!!!

[smokchsr]

hehe I think you figured out, you can only go + or - 180 deg.. -181 will show as +179.. Or at least that's the way it works with most test equipment.