Submerged question

[darkfibre]

Hi,
I need to do some underwater work, but have not sealed my coil.

I am considering winding another coil for underwater use (Surf PI) but instead of sealing it, leaving it open to the water (but sealed conductor)

I understand that it will effect the coil, but would it be usable?

Too hard to tell?

Should I try it and report back?

[Polymer]

Hello darkfibre,

I posted a similar question (I think) around two years ago (connecting ground of coil to saltwater for capacitive shielding).
http://www.geotech1.com/forums/showt...ossing-my-mind.

As far as I understand nowadays an open coil would have a much higher self capacitance due to water having an extremely high dielectric constant.
That would be around 80 as compared to air = 1.
That would make your coil much "slower", too slow perhaps, but it depends on what you are are searching for I suppose.

I have not tried grounding my coils in seawater yet, as I am still trying to find out what is causing the warble/beat frequency on my surf PI builds.

Have you tried a non sealed coil in saltwater yet? What happened? If not, please give it a shot and report back.

I will be getting a portable oscilloscope soon (weeks) and would love to set up directly at the beach to test this kinda stuff
and see what happens to the waveforms when dunking coils.

I am on little island in the sea too with limited possibilities. Never thought I would be looking at everything from a "can I use this one day, perhaps" viewpoint.
I got lucky a few days ago, found a kids plastic beach shovel with a sturdy 19mm shaft, just what I needed but couldnt procure anywhere.

If you are still on the island, I can feel with you. I sometimes envy others with free/cheap easy-peasy - only takes a few days - delivery services.

Hope all is well, Polymer

[jladre]

Guys Do you mean exposing the winding to saltwater? If that so then i've trued it already and results is ugly.. you can leave your coil unshielded but not unsealed.