Measuring velocity factor
This article discusses measuring velocity factor using the NanoVNA. The DUT is coax with N type connectors as it provides a better example to demonstrate and learn from. Having acquired competency, extension to two wire lines is just a matter of attending to the matters of a suitable transformer, and appropriate SOL calibration parts.
N type connectors
The ‘standard’ reference plane on N connectors is shown in the diagram above. For the purpose of this article, length measurements were made between the reference planes at both ends of the cable. Continue reading On testing two wire line loss with an analyser / VNA – part 6
At 4NEC2 plots of STL VSWR and 4NEC2 plots of STL VSWR II I explained a method of working around a limitation of 4NEC2 values for Zo that can be applied using the Settings menu.
I can advise that exactly the same change works in 4NEC2 v5.9.3
It appears that 4NEC2 enforces a requirement that Zo>=0.1, so having discovered that by trial and error, one wondered if it was possible to change that threshold by hacking the exe file. Continue reading 4NEC2 plots of STL VSWR II (v5.9.3)
InsertionVSWR of Chinese 1-9 balun module showed a 450Ω load attached to the DUT, and I have been asked to explain further.
Above is the load resistor just visible to the left of the spring terminals on the module. The idea is that the leads need to be very short to avoid unintended / undesired impedance transformation. Continue reading InsertionVSWR of Chinese 1-9 balun module – that load resistor
This article documents an InsertionVSWR test of a cheap Chinese 1-9 balun purchased for less than <$5 on eBay (shipped).
Above is a 1-9 balun, it would seem to be a clone of the Noelec 1-9 balun. The balun is a compensated voltage balun with the secondary centre tap grounded for these measurements. Continue reading InsertionVSWR of Chinese 1-9 balun module