Phase



Okay, I give up. Under the Display/Format menu is "Phase". In ham radio, what would be a practical use for this function? Thank you...



One practical use of the VNA phase measurement would be in adjusting the phase of the feeds to a multi-radiator antenna.
A pair of stacked vertical dipoles can increase gain in the horizontal direction. If such an antenna is placed on a mountain top, it may be desirable to change the relative phase of the two dipoles to aim the pattern down toward the lower surrounding terrain. Measuring the phase of each splitter+cable feed can allow this to be properly set.
--John Gord

On Tue, Sep 24, 2024 at 04:12 PM, <avionicsfun@...> wrote:


Okay, I give up. Under the Display/Format menu is "Phase". In ham radio, what
would be a practical use for this function? Thank you...



Also, the phase of the reflection coefficient (s11) and the phase of the impedance cross 0 at the resonant frequency of a resonant circuit. So looking at the phase trace gives a good way to measure the exact resonant frequency. This is useful to see the resonant point of an antenna or an LC trap.

1 Людина сподобалось це


On Tue, Sep 24, 2024 at 04:12 PM, <avionicsfun@...> wrote:


Okay, I give up. Under the Display/Format menu is "Phase". In ham radio, what
would be a practical use for this function? Thank you...
The typical NanoVNA only measures the phase of the reflection coefficient (S11) which is NOT the same as impedance phase. Recent firmware from DiSlord also calculates the impedance phase angle and you can select it from the menu.

Here is a plot of a 20 M antenna feedpoint showing the measurement of the two. Note how both cross at zero when the antenna is resonant.

Roger