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Jason,

As an ex-employee of M/A-COM I can vouch for what you learned. We made
special connectors for the test equipment companies, HP, Wiltron and
such. The plating should flake off any OS connector.

BeCu is not necessarily dangerous with standard machining practices
because it produces large chips & not dust during the machining
process.

A couple of other companies I worked for used BeO. It an excellent
electrical insulator and possesses the highest thermal conductivity of
commercial ceramics. We needed that for the high power circuits we
designed. It was machined under water due the dust generated by
grinding & polishing.

IMHO, the frequencies that the NanoVNA operates at & the precision we
require are not compromised by good connectors & operating practices.
These devices should not be compared to a HP VNA. They are ideal for
amateur radio use.

I use push-SMA connector savers with excellent repeatability. I believe
they were made by Adams-Russell, another M/A-COM company.

?___
Sent from my two way wrist watch
73 de W3AB/GEO?

On May 21, 2020, 12:01, at 12:01, fishtronics <fishtronics@...>
wrote:

Using the SMA-M/SMA-F adapters as connector savers like I think you
show, Stan, is a very good idea. Even very high quality SMA connectors
(>$50 each) degrade in match very quickly. Cheap ones with only 2 jaws
on the center conductor are pretty much worthless for repetitive use.

I

was once told by the ME at Omni-Spectra their SMAs were rated to meet
spec for the initial connection only! I am getting a bunch and will
swap them out as soon as any gold flaking or wear is apparent under
magnification. Most of the cheaper SMA connectors from China look to

me

to have plain brass center contacts which will not apply any contact
pressure after the first mating. A capacitive gap results. The only
inexpensive SMA-M/SMA-F adapter I can find with a Beryllium center
conductor is the Cal Test CT3673. The only reason to use BeCu which
costs more and is poisonous to machine is if they heat treat it, to
make the jaws springy. I don't know whether there are more than 2 jaws
to the F pin. Better ones have more, but at < 1GHz it probably won't
make any difference untll the jaw loses its spring. I have a question
into the tech support to ask about it. Data sheet kere:
.
They are dirt cheap at
Amazon:.
Jason NJ7K