Shielding, another topic in the series...

[ivconic]

[ivconic]

Accidental discovery... not sure how it will turn out in coil shielding...
Tape thickness is 0.019mm.
The tape is very strong and will not suffer any damage while wrapping around the coil.
I haven't tried it yet... is this even worth trying?
I have "miles" of this tape in my attic!

[Carl-NC]

If that's really megohms, then no, too high.

[ivconic]

Yes it is.
Guess what the tape it is?
VHS tape!

[ivconic]

Second, it is "conductive" only on the "inner" (bottom) side and not the other way around.



Once, I ran unimer probes over the black epoxy on a Fisher coil and once over the black coating inside the White's coil.
With the Fisher coil (Quicksilver), the resistance was consistently around 2 megohms, no matter how far the unimer probes were from each other.
I can't remember about White's, but I think there was a lot of resistance as well.
The magnetic layer on the lower part of this tape first associated me with a similar material that is mixed with epoxy with which the coils are filled.

[GeoMax]

Since the topic of coil shielding is becoming topical again... I also have a question about it. We all know that a coil shield needs an air gap. How do I determine the correct distance of this air gap? Does it depend on the physical dimensions or electrical properties of the coil? I normally use an air gap of about 15 to 20 mm. Is that too much or maybe too little for a 10 to 12 inch PI coil? And what about larger coils of e.g. 15 or 20 inches? Is this distance sufficient for the air gap? Is there perhaps a formula for calculating this?

[ivconic]

Since the topic of coil shielding is becoming topical again... I also have a question about it. We all know that a coil shield needs an air gap. How do I determine the correct distance of this air gap? Does it depend on the physical dimensions or electrical properties of the coil? I normally use an air gap of about 15 to 20 mm. Is that too much or maybe too little for a 10 to 12 inch PI coil? And what about larger coils of e.g. 15 or 20 inches? Is this distance sufficient for the air gap? Is there perhaps a formula for calculating this?

Good question... to which I do not have an adequate answer!
I always left a 5-8mm gap on my coils.

[ivconic]

I have an old 8" Fisher coil shell (1265) and a White's "xxxMax" coil shell... obviously the situation is not the same...

[ivconic]

...
As I write this I am simultaneously watching a live broadcast of the solar eclipse in Mazatlan, MX.
Torreon, MX...
Solar flares can be seen around the rim of the "black ball"...
...
No doubt; Mexico is doomed now!
Who is next?

[ivconic]

Anatoljioooooo be careful!
"They" are coming for you!

P-S-
@KT315...

[ivconic]

[kt315]

Anatoljioooooo be careful!
"They" are coming for you!

P-S-
@KT315...

thank you for the warning. I hope Yellowstone volcano is yet sleeping.

[ivconic]

The eclipse is just now visible in Texas... and it goes north...did you notice that Carl suddenly disappeared from the forum!??

[Carl-NC]

How do I determine the correct distance of this air gap?

I typically use 5mm. The gap forms a capacitor so you want to make sure the gap impedance stays "high enough." Even at the highest frequencies, 5mm is probably plenty. I've even thought about overlapping the end of the shield with the beginning, with an insulation layer in between. Never tried it, though.


No eclipse here, I'm in Washington state (west coast) near Canada. We had a total eclipse a few years ago.

[pito]

Minimum gap 1mm



overlapping