ICP coil first test

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Richard Hull
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Re: ICP coil first test

Post by Richard Hull » Mon Apr 12, 2010 4:21 pm

Having run unshielded 15kw in copper coils in Tesla coils, the LF stuff is no worry. More interesting and probably more likley is heating nearby junk inductively that you would not normally think about like bolts, etc.

I was stunned about the eye warnings. Just not an issue, of course. More likely is roasting your belly button or being branded as your closed loop belt buckle heats in the near field of the coil.

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Carl Willis
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Re: ICP coil first test

Post by Carl Willis » Mon Apr 12, 2010 4:50 pm

That copper-in-glass coil certainly is unusual...and probably cost a fortune. Would have been fun to see the glassblower at work on that. What was the rationale behind this construction?

Your test plan looks fine. It's good that you plan to start at low power. As you've been advised before, put a long piece of cable between the rf generator and the matchbox to help protect the rf generator. Watch your fingers near the coil or you'll get flamed.

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Re: ICP coil first test

Post by Linda Haile » Mon Apr 12, 2010 7:08 pm

Fair enough, Dustin, but these multi-killowatt RF generators can still cause RF burns.

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Re: ICP coil first test

Post by Linda Haile » Mon Apr 12, 2010 7:19 pm

These multi'killowatt units will still 'boil your head' if it gets too close.

I was erring on the safe side when I mentioned blindness as no-one else was posting at the time.

Safety was the issue. How about a FAQ on RF generators?

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Re: ICP coil first test

Post by Carl Willis » Mon Apr 12, 2010 7:58 pm

Steve's plan makes it clear that at most he'll have no more than a few dozen watts of delivered power (enough to light a fluorescent bulb).

Unlike earlier ideas that implied multi-kilowatt testing with the supply at full excitation, this is a logical and safe place to start. Nobody's head will be "boiled," nor will any of the other fairy-tale consequences trotted out at the beginning of the thread be realized. Just to put things in perspective, the old diathermy machines for home use developed 100-200W in the HF or low VHF bands (and besides heating flesh, will light fluorescent bulbs in spectacular fashion). Sun-Kraft lamps develop a few dozen watts at 18 MHz with a tube oscillator in the base; touching the open feeders at the UV bulb will brand your hide but otherwise is of little concern.

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Re: ICP coil first test

Post by Linda Haile » Mon Apr 12, 2010 8:54 pm

But what about a multi-killowatt unit running at peak power, Carl?

I'm as interested as everybody else. Are you saying it won't 'boil my head'?

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Re: ICP coil first test

Post by Carl Willis » Mon Apr 12, 2010 11:01 pm

I'm not commenting on the possibility of boiling one's head in circumstances outside of what Steve described, which was a low-power test that carries the risk of minor RF burns and that's about it.

Realism ought to temper and inform the cautionary lecturing or it loses its relevance. Commenters hung up on boiled heads and whatnot in this thread should read Steve's plan over again and consider whether such response is apropos to the real situation, or whether it is a fanciful cautionary tale a la Struwwelpeter. Also, the preferred responses relate to direct experience rather than received "folk wisdom," which is what I think this stuff about blindness and boiled heads is likely to be.

Rf (and its hazards) are well-understood by hobbyists. The amateur radio hobby is replete with knowledgeable people, useful online and printed expert resources, forums, list servers, and so on. I don't think rf generators merit a FAQ. If the level of experience and interest rises, there might be a reason for the experienced parties to write one. But right now I think that endeavor would just be an instance of hot air.

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Re: ICP coil first test

Post by AllenWallace » Tue Apr 13, 2010 3:31 am

A quick google search shows that to keep below the FCC radiation limit you should keep 9 feet away from a 14 Mhz dipole transmitting 1 KW.

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Re: ICP coil first test

Post by Richard Hull » Tue Apr 13, 2010 1:36 pm

All such government radiation limits are set based on rather continuous exposure or at least long term exposure. You will not become a piece of bacon at 1KW even right up next to the coil so long as you are out of arc range. Just watch out for metal stuff on your body or metal stuff in the vacinity that you might touch or lean up against. More much ado about nothing.

If you get cooked you are stupid. If you don't read or have prior knowledge about what you are doing then you deserve the RF burn, exploded head, or loss of life and limb.
It is nature's way of thinning the herd of nebishes and the non-fleet of foot.

We are not thought or activity police here. Simple advisories are OK, but dire, out of the realm portents of impending doom are enough to put you off marriage, eating, or having a bit of fun. The world used to be a wonderful place when I was a kid....Full of endless enjoyments and possibilities. Now I have to worry about lead in paints, toys choking children, asbestos, metals in my water, an unlimited number of cancers due to consuming the wrong foods, mercury in fish, asteroids and meteors ending the world, the ozone layer depletion, the magnetic poles disappearing, global warming, global cooling, nuclear winters, terrorists, religious zealots, run away Toyota hybrids, skyrocketing energy costs, run away inflation, collapse of global finanical markets, my job, and the list goes on ad infinitum.

Have fun......If you dare.

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Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
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Re: ICP coil first test

Post by Linda Haile » Tue Apr 13, 2010 5:52 pm

Carl, these multi-killowatt units do have suffieient power to 'boil your head'. Steve had said he would start on low power, and turn it up. He now has a greater understanding of what he is dealing with.

RF and microwave radiation heat up the soft tissues in the body. The lenses in your eyes are soft tissue and cannot dissipate the heat. There is a risk of impaired vision even with RF if you are close enough to it or the power is high enough.

There is no such thing as a 'minor' RF burn and accidents do happen even to experienced RF technicians.

At least Steve is safe,

We should be getting one of these units next week. While they are a lot safer than magnetrons they still pose risks to health, especially the multi-killowatt units.

I stand by what I said. (Better safe than sorry).

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