On Tue, Jan 19, 2021 at 12:07 PM, Jim Lux wrote:
For HF work, banana plugs and jacks might be a "fast to change"
fixturing thing. the 0.75" spacing and similar length is a tiny fraction
of a wavelength at 30MHz.
My reference plane is not at the 0.75" jack terminals. I use double sided PCB material with both sides connected together and a small slit in the middle to complete the jig. The reference plane is at the PCB slit. It works OK up to about 150 MHz where the "lumpy" impedance is not calibrated out very well. As the load impedance goes up the effect of the jig and the NanoVNA error becomes evident. The plots below show what kind of results to expect.
Roger Need
