It’s been a while since I last posted something here. Recently, I measured the insertion loss of a couple of coaxial cables that I had using my NanoVNA.
I wanted to select a feeder cable for a 20m dipole. I had a length (almost 43m) of RG58C and a shorter length of unknown coax used by telecommunication service providers.
And this was a good chance to see the NanoVNA in action.
Configuring NanoVNA
- Set the frequency range
- Do a SOLT Calibration
- Keep S21 Logmag and hide all other traces
- Use appropriate connectors and connect both ends of the coax to PORTs 1 and 2
Results
See the difference in the curves. I have added markers for 40m, 20m and 2m frequencies for reference. The cable used in telecomms shows barely minimum loss even at VHF.
Just for fun, I compared the measured results of RG58C with the calculated ones using this calculator.
Right on the money!
