[TowerTalk] Understanding Coax Loss Measurements

[Jim Brown]

On 11/28/2020 3:43 AM, Kirk Kleinschmidt via TowerTalk wrote:
> I'm trying to characterize some coaxial cables and various connectors, and the results from my two measuring methods aren't reconciling well. My understanding of the tools is also less than complete.

First, make sure that your VNA is well calibrated. For cailbration, you 
will need standard Open, Short, and 50 ohm parts.

Then, use it to make S11 measurements over the frequency range of 
interest. I'd go with 1-50 MHz. Then download a copy of AC6LA's ZPlots 
Excel spreadsheet, export your data to it, and follow his instructions 
for characterizing the cable.

This will give good results for coax and two wire line of any impedance.

73, Jim K9YC