[time-nuts] Query about insulated coax panel connectors?

[Michael Wouters]

Dear Jim

These, in conjunction with some M6 nylon washers, work OK for
isolating an SMA bulkhead feedthrough from the case:
https://www.minikits.com.au/components/hardware/washers/Metric-M6-Washers
(the nylon shoulder washers down the bottom)
The connector will rotate though if you try to torque up the SMA nut -
you can really only make them finger tight.

Otherwise, you can buy isolated bulkhead feedthroughs eg
https://www.fccable.com/SMA-Female-To-SMA-Female-Bulkhead-Isolated-Ground-Adapter/2068/A1636/
or
https://www.centricrf.com/adapters/sma-adapters/sma-to-sma-bulkhead-adapters-18ghz/c3150b-sma-f-f-isolated-ground-bulkhead-adapter/
I never found anything cheaper than about $US20 per connector.

Cheers
Michael


On Sun, Oct 25, 2020 at 7:44 AM AC0XU (Jim) <James.Schatzman at ac0xu.com> wrote:
>
> Time-nuts:
>
> Having recently run into major ground loop noise issues, I have begun reworking some of my homemade pieces of equipment using insulated coax connectors. My goal is to have one ground connection only in the cases, and that is at the power entry point, either a power cord or the outer terminal of a DIN. I am also installing isolation baluns on inputs and/or outputs.
>
> Insulated BNCs are readily available. Others not so. In some cases, there is not room to install an insulated BNC. I am not finding any insulated SMA, SMC,  SSMA, or SSMC despite googling and searching catalogs.
>
> Does anyone know of a source for insulated small threaded coax panel connectors?
>
> Another option would be a compact insulating bushing that an SMA panel connector, for example, could be mounted in. I am not finding anything like that either...  In fact the ideal solution would be an insulated SMA with an integrated 1:1 balun.
>
> And I am not thinking about using plastic cases - that would introduce a whole other set of problems. I think about my lab area at work where a bundle of dozens of gigabit ethernet cables run through the roof directly over the lab bench - the ambient noise level is quite high.
>
> Suggestions???
>
> The only idea I have some up with is to design something myself, possibly 3-D printed...  Any suggestions about how to get started on something like that?
>
> Thanks in advance-
> Jim
>
>
>
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