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Re: EMR

In a message dated 10/28/98 10:55:35 AM Pacific Standard Time,
tesla-at-pupman-dot-com writes:

<< 
 1.)  In a few days I hope to run my coil outside. I've never done this 
 before. I'm hoping someone can tell me what kind of affect it might have 
 on television and radio reception? My coil is 6.5" in diameter. I will 
 be running at 5-9 kw. The nearest home other than my own is 75' from the 
 coil centerline. The frequency of the coil is about 220 KHZ.
 I have a very good RF line filter. When I run the coil indoors I get 
 only mild interference. The problem with running inside is that it arcs 
 to everything. I've only got about 75" to play with. The furnace has 
 taken some pretty good hits and last week it hit my contactor 81" away. 
 That was the end of the contactor. 
 
 2.)  My transformer has a single HV terminal. The tank circuit will be 
 grounded at one end and the primary and secondary as well. I'm using a 
 standard 8' long ground rod. Will this have the same effect as tying the 
 primary and secondary together ? (60 hertz componet)
 
 Thanks,
 
 paul m. 
  >>
Paul,

Your coil is similar in size and power to mine.  Sounds like you are getting
into the high performance with 81" sparks.  If your resonant frequency is 220
khz, it tells me that your toroid is way too small for that kind of power.
How large is your toroid?  With a 6" secondary and two toroids, one 33" and
one 40", my resonant frequency is about 130 khz  --  and I think I need to
build a larger toroid still.  Also, I think with   5 - 9 kva you would benefit
with more than one 8' ground rod.

I haven't built a Tesla coil with a grounded secondary but have seen the
schematics for them.  I live out in the country and the closest neighbors are
probably 1/4 mile away.  75' is kind of close.  I would definitely invite them
over to watch - get them involved.  Then have them go look at their TV while
the coil is running.  I would expect the noise to be a larger issue than the
minor interference it may cause.  You need an evening with little or no
breeze.  Any wind at all will cause the resonant frequency to shift around as
the ion cloud around the toroid comes and goes.  Welcome to the high power
club - once you move outside you will get a better idea what the system is
really capable of.  It is a bit of a pain for me, it takes about 1/2 hour for
me to haul everything out of the garage and get it all set up.

Ed Sonderman