I was reading this thread and all the concerns about oil in the capacitor. Has
anyone ever thought about trying SF6 as a dielectric? It's commonly used in
high voltage (hundreds of kilovolts) switchgear by utilities.
Just a thought, more curiosity than anything else.
-Bill
Sent from my iPhon
On Jan 30, 2014, at 5:32 AM, "Tom W8JI" <w8ji@w8ji.com> wrote:
> Still I am intrigued by the thought of a remote tuning capacitor via
> hydraulic tubing :-). The capacitor plates could be as simple as two
> concentric cylinder conductors with appropriate spacers. I betcha crud
> collecting on the top of the oil would set voltage limit.>>>
>
> I would be as concerned, or more concerned, with the dissipation factor of
> the oil at short wave frequencies.
>
> The thing that worries me is I cannot recall every seeing a single good
> high-Q oil-dielectric capacitor above power line and audio frequencies. As a
> matter of fact, many years ago I tried to use a surplus 20-40kV oil capacitor
> from Fair Radio as a plate blocking capacitor, and it overheated so badly it
> exploded.
>
> I looked for HF data on mineral oil as a dielectric and couldn't find
> anything. That would be my main concern. I guess I could stick mineral oil
> between the plates of a capacitor and see what happens to Q.
>
>
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