kb8tq@n1k.org said:

What's available in the way of glass-metal seals for coax?  (The antenna
signal has to get in somehow.)

--
These are my opinions.  I hate spam.

On 12/1/20 11:03 AM, Hal Murray wrote:

Vacuum tight hermetic feedthroughs - we use them all the time in thermal
vacuum testing to get the wires through the wall of the chamber.

They come in two kinds - O-ring sealed and "braze in"

On a smaller scale, there are plenty of hermetic RF (and non RF)
connectors used on sealed assemblies that get leak tested. Usually, it's
a "braze in" sort of thing where you have a hole that's "slightly"
larger, and you drop the thing in.

It's a "well understood and mature" technology, if a bit expensive.

Sub-D, multipin round, thermocouple wires, fiber optics, etc. they're
all available.

I've used modified spark plugs as a HV hermetic feedthrough.

Hi

You are going to fabricate the “base” as a solid piece. Getting a coax style connector
into that is just a matter of your credit limit. The larger issue on the device is making the
“cover” out of metal. That probably isn’t going to work very well :) Now you are off into
a glass cover of some sort with a weld flange on it. If you thought the tooling on the
coax connector was exciting, it just took second place …

==========

The bigger question is: If you had the choice of a > $5,000 version of this device that
would not fail from (internal) humidity, would you buy a few thousand of them? My guess
is that you would still buy the $250 ( I think that was the original price …) version and
a couple of spares.

I’d bet more of them die from lightning hits than from humidity.

Bob