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On Tue, 9 Jun 2020 at 18:13, Wes Plouff <ac8jf@...> wrote:

I received my NanoVNA-H4 from AliExpress in just 10 days, and am happy
with my purchase. However, the 50 ohm SMA calibration load goes
intermittently open. The cap rotates even when the load is screwed firmly
to the VNA port connector, so I think the part is defective. The
calibration load from my hugen NanoVNA works properly on the H4.

What are good sources for a replacement part that have good performance to
1.5 GHz, are reasonably priced, and ship from the USA? Am I stuck buying an
entire calibration kit? Thanks for any advice.

A Minicircuits KARN-50X+ is a pretty decent male load. Mechanically they
are good, and do not rotate as you screw them in. However, unless you
either pay lots of money, or pay someone to measure one for you, there's
never any guarantee of what it will be like. But Minicircuits have a
specification, and 99.999% of their devices meet that specification. You
may find another Minicircuits load with a better guaranteed performance to
a few GHz.