[time-nuts] EOL Motorola Oncore Remote Antenna

[jimlux]

On 12/1/20 11:03 AM, Hal Murray wrote:
> 
> kb8tq at n1k.org said:
>> Yes, there’s more to it if you want to get connections in and out. Forget
>> about  “hermetic” connectors, they aren’t up to the task. You need glass to
>> metal seals  embedded in the structure. Now you have even more constraints on
>> the package.
> 
> What's available in the way of glass-metal seals for coax?  (The antenna
> signal has to get in somehow.)
> 

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.