Well, my HP was calibrated decades ago before I retired. and like you say
for fun stuff it is good enough. I prefer to roll my own now. Close
enough is good for me.
Mel, K6KBE
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On Sat, Nov 2, 2019 at 12:57 PM hwalker <herbwalker2476@...> wrote:
On Sat, Nov 2, 2019 at 10:46 AM, Mel Farrer, K6KBE wrote:
I have a set of SS SMA PCB mount male connectors that I soldered 4 200
ohms
0603 resistors around the clock, 12,3,6,9 and it measures very close to
my
HP SMA termination.
----------------------------------------------------------------------------------------------------------------
Mel,
I used a commercially made HP 50 ohm termination as my standard until
David Taylor pointed out that even though it was manufactured by HP its
s-parameter specs were lukewarm at best. My S11 measurements on known
devices were slightly off, but that was because my NanoVNA OSL calibration
was made with a load that was slightly off. Changing to a Mini-Circuits 50
ohm load with known s-parameter specs up to 18 GHz solved the problem. To
my point, what you have observed may not reflect accuracy unless your HP
termination is well characterized.
Of course if you are just using the NanoVNA in a hobbyist environment
where measurements within 5 - 10% are acceptable, then pretty much any 50
ohm load or termination assembled using good rf techniques should do.
- Herb
