On 11/28/20 11:08 AM, Jim Brown wrote:
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
A bit of background: AC6LA's spreadsheet does the renormalization for
the different impedance, if your VNA doesn't have that feature.
(you're not using the NanoVNA, but for those who are, the NanoVNA-Saver
python program also has the "change characteristic impedance" feature)
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