开云体育

On Sunday, November 13, 2022 at 06:21:03 AM CST, Barry K3EUI <k3euibarry@...> wrote:

The “Five County Digital Training Net” (Philadelphia region) is hosting a series of Zoom Workshops on Monday evenings at 7-9 pm. The topic: Nano VNA Fundamentals
All are welcome to join.
Link:

We have already held two sessions covering the fundamentals of what a VNA is capable of measuring and the second session covered how to CALIBRATE the VNA over a frequency range.

The 3rd Zoom session on November 14th will cover what a Nano VNA measures and what it calculates: the forward and the reflected signals are compared (S11) and the following are calculated:

1) Reflection Coefficient (rho) - a fraction from 0 to 1.0 representing the ratio of returning signal to incident signal. In an antenna, you do not want any reflected (return) signal, so the ideal reflection coefficient is zero.

2) Return Loss (dB) - this is based on the reflection coefficient and represents the loss of signal, but measured in decibels (dB) rather than as a percent or fraction. Hams rarely use this measurement. Why?

3) SWR - standing wave ratio? -? We all use this term but what does it mean? What is an “acceptable” SWR in terms of antenna performance.

I will tie these three measurements into what a Smith Chart reveals.

Come join the discussion.
I am not an RF Engineer - so I try to keep this at a moderate level of mathematics.

De k3eui
Barry? (k3euibarry - at - gmail.com)
Five County Digital Net manager
Philadelphia PA
November 13 2022