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On a broadcast tower, with a 30 ohm self impedance, but a 10 ohm
operating impedance in an array, a resistance to earth (half the
radiator, as well as the coupling plane) of 3 ohms, when 1 ohm is
practical, makes a big difference.  

DK> alley" and have repeatedly had to try to teach the lesson
DK> about the need for low-reactance paths to earth there -- seen
DK> people lose literally millions of dollars worth of 
DK> electronics and electrical hardware, plus unmeasurable 
DK> amounts of business production for trying to ignore it in 
DK> that part of the country.

Have you ever seen anyone explode a concrete building floor slab? 
That's one I've only heard of, where someone had the brilliant
idea of using reinforcing mesh in the slab as a cheap alternative
to normal "open land" ground electrodes, rods, screens, bonded
radials, etc.  Up these parts, we get winter.  Down your way, I
guess you're more likely to see a glass encapsulated (and
therefore insulated) ground rod, from lightning melting the
quartz sand around the rod?  

If Richard, or anyone cares to comment, what have Tesla
experimenters used for ground references?  For those larger
coils, I would suspect an array of radials using a few miles of
#10 soft drawn Cu, with Erico welded mesh for about 50' in
the center, bonded with 4" strap, might be adequate in most
places.  Add a couple of 30' chemical grounding electrodes in
poor soil areas. Does anyone bother in high voltage experiments?  

Terry
Charges filed under Ohms Law!  (203)732-0575 BBS (1:141/1275)

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  Date: 06-21-94  17:07
  From: Mark Conway                               
    To: Richard Quick                            
  Subj: crossed wires
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
TID: FastEcho 1.40 15032

Hi Richard,

This is a repost as my original message seems to have gotten
lost in the system. I think we have been having a few problems
with fidonet lately. Anyway if you have already recieived this
message then please ignore it.

 Hey I have just finished watching your 2 videos on tesla coils (
I got copies from Jim Oliver)- boy talk about impressive!
 
I think I would be too chicken to use a power pig to power a
tesla coil - I guess if you want to go into even higher powers
you will need your own nuclear generator, or maybe you could wire
up a lightning rod and use a lightning strike as the input power
for your tesla coil- one advantage of this I spose is that you
wouldnt have to worry about a spark gap or a capacitor!
 
In your reply to my last message about crossing turns on a tesla
coil you said, The problem with crossing wires, especially on
base fed coils (such as Duane Bylunds) is that the lower turns
can act as a low voltage "ground" point. Crosses between turns
(especially on short fat coils with high interturn voltage
increases) results in tiny breakdowns in the magnet wire
insulation. These breakdowns cause excessive losses.
 
Another way to look at it is that each overlapped turn represents
an intermittant short circuit.Ó
 
I still arent quite sure how this works- wouldnt the turns just
being wound close together constitute an intermittant short
circuit or does the wire being crossed mean that their will be a
sharp point somewhere on the crossed wires that will result in
electrical breakdown?
 
Thanks for the info on salt bottle capacitors. I calculated that
to get a capacitance of 0.02 microfarad (which is what the
circuit in the tesla coil article says is required) I would need
66 big beer bottles.  Ive started collecting beer bottles (hic-
the things I have to do for science!) but I think that it will
probably be too bulky. 
 
I have your postings on making polyethylene caps. I would like
to try making these but I am not too sure about the availability
of the materials here in NZ.

Is polyethylene the same as polythene - is it the black sheet
stuff that people use for laying on their gardens to stop weeds
poking through? If it is the same then I will have no problem in
locating a supply. If it isnt could you please tell me what
polyethylene is used for in the States and maybe I could find a
supply of it over here.
 
Aluminium flashing looks like it could also be difficult to find
over here. Is it used for plumbing or roofing over there?
 
Best Regards, Mark: Infomania! - 64-9-489-6750 (3:772/195)

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  Date: 06-22-94  18:54
  From: Bob Patten         
    To: Richard Quick                    
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
-> I wish I could recommend the definitive book on Tesla coiling,
-> but I have read them all, and I still have not read IT.

I sent for two books yesterday, "Vacuum Tube Tesla Coils" and
"100 Years of Electrical Magic".

Thank you for the detailed description of how to wind a 450 khz
coil. Again, I've made a hard copy of your message.  With the
info that you've given me and the books that are on order, I'll
have plenty of material to study when I go on vacation in just
under two weeks.

Oh yes, I did build an induction coil setup using a K-Mart
universal ignition coil and a 555 timer.  It worked quite well
with various types of lamps including flourescent and a splendid
Jacob's ladder.  This satisfied my immediate craving, but I still
intend to build a Tesla Coil, something I've thought about since
I was a kid - about 40 years ago...        Thanks for your help!  
 
 (305) 472-7715  (1:369/120)
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  Date: 06-23-94  21:17
  From: Roy J. Tellason                   
    To: Richard Quick                       
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
Some of these comments are based on my recollection of that
long-ago article that appeared in Popular Electronics...

21 Jun 94, Richard Quick writes to Bob Patten:

 RQ> Get some rigid Plexi, Lexan, or polystyrene pipe/tubing with
 RQ> a thin wall. It should be ~4 inches in diameter and 21       
 RQ> inches long. Thin wall PVC drain pipe may be used but it     
 RQ> must be sanded, dried throughly, and sealed with several     
 RQ> coats of polyurethane or clear two-part epoxy paint.

They used a cardboard tube for this, a readily available item,
but I'm sure that a lot of the other materials you mention
weren't around in those days.

 RQ> Buy at least 1-1/4 lbs (~1000 feet in length) of #24 double
 RQ> Formvar (enamel) covered magnet wire.

I seem to remember that article mentioning two pounds of wire, 
but I can't remember what size wire it was.

 RQ> Wind the wire on the coil form.

Is there any easy way to do this?       :-)

When I was in junior high school we had a little gimmick that
consisted of most of the parts of a hand drill mounted on a
board,  but those were multi-layer coils wound with fabric-
covered wire that sort of resembled the kind of thing that you'd
see in a doorbell or buzzer.  I can't quite see sticking a
four-foot cardboard tube into one of these,  though.

 RQ> The windings needs to be tightly spaced, no gaps, and no
 RQ> overlaps: the winding should start 1" above the bottom of    
 RQ> the coil form. #24 magnet wire winds about 46 turns per inch 
 RQ> (TPI), the winding should be 19 inches long with ~874 turns, 
 RQ> and use up about 915 feet of the wire. The winding should
 RQ> stop about 1" below the top of the coil form.

That's pretty explicit stuff,  there.

 RQ> Never drill holes or introduce wire inside the coil form.

That article referred to wooden disks in each end of the form, 
with the bottom one having something or other to support the
thing and the top one having a big (3-4") feedthrough insulator
mounted on it.

 RQ> After the windings are sealed, I cap the top and bottom of
 RQ> the coil form with disks of plexiglass bedded in epoxy.

What do you mean "bedded in epoxy"?

 RQ> ... If all else fails... Throw another Megavolt across it!

Sounds good to me!      <grin>
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  Date: 06-23-94  18:53
  From: Richard Quick                           
    To: Terry Smith                           
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
Discussing low impedance grounds in RF work, xmitters and Tesla
coils.

 TS> From this thread, I'm getting an impression that             
 TS> broadcasters do a little more in the way of operating        
 TS> impedance calculations and measurements, and projected       
 TS> ground related base losses, than folks who stare in awe at   
 TS> man made lightning.  

Must we be forever in disagreement Terry?
Earth ground was first applied to a tuned circuit by the man who
created synthetic lightning. The same man who invented
broadcasting, and a ground based electrical transmission system
which requires no wires. How could you say that the followers of
the man who first calculated these figures would be ignorant of
his work? I will refer you first to Tesla's own writings:
Colorado Springs Notes, 1899-1900, Nickola Tesla, Nolit, Beograd,
Yugoslavia, 1978, pp12. 

Tesla writes a list of three major goals for the experimental lab
he is constructing in Colorado Springs. Number three on the list:

NT> 3. To ascertain the laws of propagation of currents through
NT> the earth and the atmosphere.

The diagrams, footnotes, and patent references from pp12-18 alone
would be sufficient to convince you the error of your
implication. If that is not enough, then I would refer you to the
pp36-37 entries for mid-month, June 15-17, 1899. Tesla proceeds
to construct a system ground for the oscillator, followed by
electrical measurement of both the system ground and the water
pipe main supplying the lab. In later work all of the major earth
resonate frequencies were plotted with amazing accuracy. The
O'scope had to wait years to be invented. In the 1950's Schumann,
Bremmer, Budden, Wait, Galejs and other authors verified all of
Tesla's "ground" work step by step. See:

> Terrestrial Propagation of Long Electromagnetic Waves
J. Galeys, New York, Pergamon Press, 1972 

 DK> alley" and have repeatedly had to try to teach the lesson    
 DK> about the need for low-reactance paths to earth there -- 

 TS> "open land" ground electrodes, rods, screens, bonded         
 TS> radials, etc. 

I knew we would agree somewhere. I have been stating this here
for a year now.

 TS> If Richard, or anyone cares to comment. What have Tesla      
 TS> experimenters used for ground references?

Me not comment? Well I can't speak for everone, but I have listed
references above that you would obviously find informative. 

 TS> For those larger coils, I would suspect an array of radials  
 TS> using a few miles of #10 soft drawn Cu, with Erico
 TS> welded mesh for about 50' in the center, bonded with 4"      
 TS> strap, might be adequate in most places.  Add a couple of    
 TS> 30' chemical grounding electrodes in poor soil areas. Does   
 TS> anyone bother in high voltage experiments?   

I ground my stuff to a buried hydraulic lift. The lift assembly
consists of a large buried oil tank, air tank, supply and control
plumbing, and the actual steel piston assembly. Run from this
ground point (which is all metal spread out over 225 square feet)
are two 1" ground straps; one strap runs to connect buried
decorative pond (1500 gallon galvinized steel tank), the second
runs to a 50' length of 14" wide aluminum flashing submerged in a
nearby creek bed. 

All coil connections to this ground are 15' feet or less for the
high powered stuff. I use the equivalent of a 2-1/2" grounding
strap from the base of the coil, and the safety gap center post,
to the lift control plumbing (both copper and galvinized steel
pipe) where it enters the ground.

While the grounding system you document would be ideal, mine
functions. I do have some idea of what I am doing. I have also
done extensive experimentation on coil systems and their
grounding requirements. I have followed Tesla's footsteps
carefully in many respects. 
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  Date: 06-19-94  11:34
  From: Jamar Neal                             
    To: Richard Quick                            
  Subj: Re: Tesla
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
> Tesla was not able to get a construction contract with his
> system in the United States, but he was awarded a contract in 
> Canada. He delivered sketches and specifications to 
> Westinghouse for a system to generate hydroelectric power from
> the Niagara river for the commercial production of aluminum 20
> miles away. The high voltage transmission was very economical.
> It appears that Tesla agreed to a one-time payment of one 
> million dollars, and the 60 cycle patents remained with 
> Westinghouse. The money was spent in the lab developing his 
> next generation projects.
 
> Tesla's system was universally adopted in one country after
> another, yet Edison gets credit for lighting the world.
 
So Tesla was the brains behind Westinghouse?  I have read a few
books on Edision and it was never mentioned that Tesla worked
there (I have to pick my book better :-))   
 
Edision often gets credit for lighting the world...but that is
because of the light bulb.  I think most people know that his DC
idea lost out.  
 
Jamar 314-339-0248 (1:287/516)

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  Date: 06-18-94  19:21
  From: Bob Patten                                
    To: Richard Quick                                
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
-> There is an excellent article in the latest issue of the Tesla
-> Coil Builders Association (TCBA) publication, "NEWS" (vol. 13,
-> #3 Jul,Aug,Sep,'94) on high powered coiling (36" spark lengths
-> running three #833 power tubes, 8+ KVA).  The previous issue
-> ran an article on a 5.2 mHz, pulse generator driven, coil.
-> ............................................................
-> Yeah, this is base feeding a 1/4 wave resonator with a high
-> current signal, a-la Colorado Springs. High Q resonators can
-> produce some pretty decent voltage rises, as witnessed by the
-> spark discharge and corona. Your efficiency in the resonator
-> had to be good, with a nice frequency and impedance match.

Thanks again, Richard!  I did a hard copy of this message also
and will study it.  I'm a real novice at this and need to sort
out a lot of info and get a better understanding of it.  Today, I
received in the mail a package from the Int'l Tesla Society which
included a comprehensive listing of the publications they have
available.  I would imagine you are familiar with what's
available and wonder if you have any further recommendations.  At
this point, I'm not sure if I want to build the conventional
spark gap type coil or go for a tube type...  Cost and
availability of parts are prime factors..
    Tnx agn.       73,  (305) 472-7715 (1:369/120)

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   Date: 06-19-94  22:04
  From: Don Kimberlin                      
    To: Richard Quick                       
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
RQ> DK> ...all the more important then, in the case of those who
DK> would build Tesla coils today, that they understand how to
DK> make really high-efficiency ones, then, eh? I know an awful
DK> lot of the Pop-Tronics "projects" of the old magazines
DK> resulted in awfully sloppy things that thrilled people with
DK> six inches or a foot of discharge, which worked out to a
DK> horrible inefficiency for the input they were running....

RQ>The goal should always be maximum efficiency. This is the
RQ>major reason that Tesla himself left two coil systems behind,
RQ>and developed the three coil system (primary, secondary, extra
RQ>coil) to industrial scale. But even some experienced coilers
RQ>need to learn the "rules of the road" when it comes to simple
RQ>coils.

RQ>A heavy, dedicated, RF ground is a must for any serious
RQ>coiling. Experiments should then seek to convert every
RQ>possible watt into spark, where the energy is consumed as
RQ>heat, light, sound, etc..

RQ>The coil base wire is the source of most of the spurious 
RQ> signal.

RQ>The output here is a low voltage RF current at quite a few rms
RQ>amps. The signal seems to conduct better than it radiates, so
RQ>just make sure your ground path is equipped for it.

RQ>Remember too that spark gap Tesla Coils are disruptive. The
RQ>output from coils excited by spark gap tank circuits does not
RQ>radiate well, and is a far cry from CW. Properly designed,
RQ>wired, and grounded, spurious emissions from most coils will
RQ>not cause a problem in the immediate household, much less
RQ>outside. At very high power, when deliberately radiating, or
RQ>when running out of tune; coils should be set up and operated
RQ>in a shielded environment such as a Faraday cage or shielded
RQ>rooms.

...Looks like we're here in an environment where the emphasis is
on a maximum induction field, which is kind of interesting,
because most everything we have done in later times is to attempt
to minimize the induction field, or at least let it die out at
short range.  Conversely, it appears the first "radio" people,
and I note even Marconi when in his low-frequency radio years
(before his stuff was for all practical purposes expropriated by
both the British and U.S. governments), was concerned with
trying to make maximum use of the induction field.  There's quite
a bit of debate about a Kentuckian named Stubblefield who appears
to have made a "radio" that used an induction field, and he's
been rather discredited for having done so.

...My own background in high-powered radio (and Terry Smith's,
btw) have taught us both about the important of a low-reactance
interface to earth.  I grew up down in Florida's "lightning
alley" and have repeatedly had to try to teach the lesson about
the need for low-reactance paths to earth there -- seen people
lose literally millions of dollars worth of electronics and
electrical hardware, plus unmeasurable amounts of business
production for trying to ignore it in that part of the country.

...So, are those "three-coil" Tesla coils connected in a sort of
induction-aiding 120 degree phase relation, rather than simple,
shall we call it, "push-pull," or is the object more in the form
of trying to maintain the average higher so the peak can get even
higher than in a 180 degree arrangement?

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  Date: 06-24-94  16:37
  From: Richard Quick                             
    To: Mark Conway                                
  Subj: crossed wires
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
 MC> This is a repost as my original message...

No, I never saw the first one. 

 MC> Hey I have just finished watching your 2 videos on tesla     
 MC> coils ( I got copies from Jim Oliver)- boy talk about        
 MC> impressive! 

Thank you for the vote of confidence.

 MC> .... crossing turns on a tesla coil...

 RQ> ... the lower turns <on a coil> can act as a low
 RQ> voltage "ground" point. Crosses between turns (especially on
 RQ> short fat coils with high interturn voltage increases)       
 RQ> results in tiny breakdowns in the magnet wire insulation.    
 RQ> These breakdowns cause excessive losses. Another way to look 
 RQ> at it is that each overlapped turn represents an             
 RQ> intermittant short circuit.

 MC> I still arent quite sure how this works- wouldnt the turns   
 MC> just being wound close together constitute an intermittant   
 MC> short circuit or does the wire being crossed mean that their 
 MC> will be a sharp point somewhere on the crossed wires that    
 MC> will result in electrical breakdown? 

OK, first off my use of the word "ground" should better be
described as an electrical node. The base of a coil is a low
voltage electrical nodal point. The voltage in a Tesla coil rises
as the wire get closer to the 1/4 wave, or high voltage, node
(usually the air terminal). Since the voltage rises steeply up
the coil, high interturn voltages exist. When turns are crossed,
micropunctures can develop in the enamel insulation at the
location of the overlap. No sharp point is required for
insulation breakdown in coil resonators.

 MC> to get a capacitance of 0.02 microfarad...
 MC> ... I think that it will probably be too bulky. 

I know a guy that used 5 gallon plastic (polyethyene) buckets
full of salt water and nested together...
 
 MC> Is polyethylene the same as polythene - is it the black      
 MC> sheet stuff that people use for laying on their gardens to
 MC> stop weeds poking through? 

Yes, my MERCK index indentifies "Polythene" as a brand name for
polyethylene. The polyethylene grade used for coiling is a 
milky-clear plastic sheeting, used in the construction trade for
waterproofing, or sold by the yard from plastic specialist.
Thinner grades (measured in thousandths of inches here) are
typically 4-10 mils thick for plastic freezing bags, trash bags,
drop cloths, etc.

 MC> Aluminium flashing looks like it could also be difficult to  
 MC> find over here. Is it used for plumbing or roofing over      
 MC> there? 

Roofing, edging. It is sold here by the roll in hardware stores.
It is stiff sheet aluminum, cut into a strip say 14 inches wide
and 50 feet long. The strip is rolled up for retail sale.

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  Date: 06-22-94  14:51
  From: Don Kimberlin                   
    To: Jamar Neal                          
  Subj: Re: Tesla
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
JN>So Tesla was the brains behind Westinghouse?  I have read a
JN>few books on Edision and it was never mentioned that Tesla
JN>worked there (I have to pick my book better).

...I have an English-written book that makes a bit of mention of
Tesla's contributions to Westinghouse...but it then goes on to
tell more about the acrimonious debate over AC versus DC power.
They even had some incredibly stupid things like getting the
Prince of Wales to hold some DC wires, to "prove" that DC was
"harmless to humans!"

JN>Edison often gets credit for lighting the world...but that is
JN>because of the light bulb.  I think most people know that his
JN>DC idea lost out.

...ah, but the British history also mentions a Swan in England
who they claim beat Edison to the lightbulb punch.  Edison fought
quite a patent battle with Swan in England and wound up getting a
draw at best...and Swan wound up making the light bulbs there, as
I recall from the book (need to check it again before saying that
for certain...)    Concord,N.C. (704)792-9241  (1:379/37)

ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Date: 06-24-94  16:54
  From: Richard Quick                             
    To: Roy J. Tellason                            
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
Talking about coil construction...

 RQ> Get some rigid Plexi, Lexan, or polystyrene pipe/tubing with 
 RQ> a thin wall. 

 RJT> They used a cardboard tube for this,  a readily available   
 RJT> item,

PVC thin wall plastic "drain" pipe that has been sanded and
sealed is generally better than cardboard.

 RJT> but I'm sure that a lot of the other materials you mention  
 RJT> weren't around in those days.

No modern materials were not around, but this does not mean they
should not be used. Older coils were plagued with low efficiency
and unreliable operation. Many "classic" coils and projects of
this nature were full of errors and misconceptions. With modern
materials (and designs and schematics that utilize them) at my
fingertips I would never look back. 

 RQ> Wind the wire on the coil form.

 RJT> Is there any easy way to do this?       :-)

I set up a spindle through the center of the coil form, and roll
the form with one hand while feeding wire with other.

 RJT> That article referred to wooden disks in each end of the    
 RJT> form,..., 

 RQ> I cap the top and bottom of the coil form with disks of      
 RQ> plexiglass bedded in epoxy.

 RJT> What do you mean "bedded in epoxy"?

I mean smear a thick enough bead of epoxy on the cap and the end
of the coil form so that the epoxy is forced out when the parts
are fitted.
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Date: 06-24-94  07:50
  From: Dave Mcknight                             
    To: Terry Smith                              
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
TS>If Richard, or anyone cares to comment, what have Tesla
  >experimenters used for ground references?  For those larger    
  >coils, I would suspect an array of radi using a few miles of   
  >#10 soft drawn Cu, with Erico welded mesh for about 50'the     
  >center, bonded with 4" strap, might be adequate in most
  >places.  Add a couple of 30' chemical grounding electrodes in  
  >poor soil areas.  Does anyone bother in high voltage           
  >experiments?

I'm just getting into Tesla experimenting myself.  For my small
coils I use two 5' copper pipes driven 6 feet under, about 5'
apart. These are connected together and run to my garage with 2
10ga. copper cables. When I'm running the power up, I take the
garden hose out and soak down the area before firing the coil.  

Your mention of "chemical grounding electrodes" intrigues me. Can
you suggest a chemical that I could soak into this area to
enhance the grounding without destroying my lawn?  When planting
my grounds I scooped off the sod then dug out about 1 ft. of dirt
before driving the rods, then reburied the tops after I finished. 
No mowing problems, no copper pegs for kids to trip and injure
themselves on.  Since the stakes are in the middle of my lawn,
something like rock salt would probably not be beneficial.
(614)861-8377 (1:226/110)

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  Msg#: 7532            Rec'd                        Date:
06-24-94  10:47
  From: Don Kimberlin                                Read: Yes   
Replied: Yes
    To: Richard Quick                                Mark:        
            
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
ÄÄÄÄÄÄÄÄÄÄÄÄÄ
RQ>Talking about Tesla Coils...

RQ> DK> ...Looks like we're here in an environment where the
DK> emphasis is on a maximum induction field, which is kind of
DK> interesting, because most everything we have done in later
DK> times is to attempt to minimize the induction field, or at
DK> least let it die out at short range.

RQ>Yes. A Tesla coil is a resonate transformer. The "transformer"
RQ>part means that the system involves energy exchange by
RQ>induction. But it is not simply producing a "maximum induction
RQ>field", but of producing a field of proper intensity and shape
RQ>around a resonate inductive structure (coil).

...OK, that sounds like there is concern for somehow "shaping"
the induction field around a core, rather than merely letting it
assume some random proportions, and attempting to couple to it.
Or am I zooming off on a tangent?

RQ>It boils down to proper mutual inductance between primary and
RQ>secondary, known to coilers as "the coefficient of coupling".

...Oh, boy, shades of some of the most hateful questions on the
old FCC First Class license test from back in the 1950's!

RQ> DK> Conversely, it appears the first "radio" people,
RQ> DK> and I note even Marconi when in his low-frequency radio
RQ> DK> years...

RQ>Bahh, Marconi worked for Tesla for nearly a year, before 1891,
RQ>and stole a lot of technique, not to mention nine key patents.
RQ>I am adverse to crediting thieves.

...Now, THAT's interesting to me!  So Marconi hung around Tesla,
eh?  All the histories I've read seem to make no mention of any
connection between them.  They at best describe Marconi as having
had the advantage of being wealthy, then marrying a daughter of
the Irish Jameson (whisky) family, which got him into British
society after the Italians ignored his efforts...I *must* get
into a Tesla history book one of these days!

RQ> DK> ...My own background in high-powered radio (and Terry
DK> Smith's, btw) have taught us both about the important of a
DK> low-reactance interface to earth.

RQ>Tesla was the first to apply ground to a tuned circuit if that
RQ>says anything. No ground used in Tesla work can be too heavy.

...It may, in fact, really say something, because what we seem to
see in the histories is Hertz in his physics lab, with everything
balanced and floating above ground, then Marconi tying "radio" to
ground.   Certainly makes sense that Tesla conceived of that
change to use the earth for one side of the circuit...

RQ> DK> I grew up down in Florida's "lightning alley" and have
RQ> DK> repeatedly had to try to teach the lesson about
RQ> DK> the need for low-reactance paths to earth there -- seen
RQ> DK> people lose literally millions of dollars worth of
RQ> DK> electronics and electrical hardware, plus unmeasurable
RQ> DK> amounts of business production for trying to ignore it in
RQ> DK> that part of the country.

RQ>And it seems no ground used for lightning can be too heavy.

SET JOHN_WAYNE.SYS /on

...yuh got that right, Pilgrim.  People have a hard time with the
concept that the earth does not have unlimited ability to conduct
electricity away from a point contact.  Oh, electric power
engineers know this, but the general public...and strangely
enough, even modern EE's working on PC boards have to grasp the
notion about peak pulse currents in a "ground plane" on a PC
board.

RQ> DK> ...So, are those "three-coil" Tesla coils connected in a
DK> sort of induction-aiding 120 degree phase relation, rather
DK> than simple, shall we call it, "push-pull," or is the object
DK> more in the form of trying to maintain the average higher so
DK> the peak can get even higher than in a 180 degree 
DK> arrangement?

RQ>The third coil is not inductively coupled to the primary/
RQ>secondary. The best way to describe the third coil is to
RQ>simply call it an uncoupled resonator which is base fed by
RQ>transmission line. The transmision line I commonly use is
RQ>simply a heavy conductor run from the top of the secondary to
RQ>the base of the extra coil some distance away.

RQ>Adding the extra coil causes a shift in the secondary output
RQ>from 90 degrees (1/4 wave) to 45 degrees (1/8) wave in the
RQ>most efficient experimental systems. This means the secondary
RQ>is no longer sparking, but shifts to supplying current, by way
RQ>of transmission line, to the uncoupled third coil. This third
RQ>coil is allowed to resonate freely, unrestricted by the
RQ>inductive coupling between primary and secondary.

RQ>It has the effect of allowing circuit designs and/or modifi-
RQ>cations which breaks the 50% efficiency barrier for resonate
RQ>transformers. I believe three coil designs are possible that
RQ>are as high as 95% efficient.

...Sure seems like that would have an effective use in radio
transmitters.  Ever hear of anyone doing it there?  They do work
to achieve the highest energy transfer, but to my experience,
only with a single primary and secondary....
 (704)792-9241  (1:379/37)


ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Date: 06-23-94  18:53
  From: Richard Quick                         
    To: Terry Smith                             
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
Discussing low impedance grounds in RF work, xmitters and Tesla
coils.

 TS> From this thread, I'm getting an impression that             
 TS> broadcasters do a little more in the way of operating        
 TS> impedance calculations and measurements, and projected       
 TS> ground related base losses, than folks who stare in awe at   
 TS> man made lightning.  

Must we be forever in disagreement Terry?
Earth ground was first applied to a tuned circuit by the man who
created synthetic lightning. The same man who invented
broadcasting, and a ground based electrical transmission system
which requires no wires. How could you say that the followers of
the man who first calculated these figures would be ignorant of
his work? I will refer you first to Tesla's own writings:
Colorado Springs Notes, 1899-1900, Nickola Tesla, Nolit, Beograd,
Yugoslavia, 1978, pp12. 

Tesla writes a list of three major goals for the experimental lab
he is constructing in Colorado Springs. Number three on the list:

NT> 3. To ascertain the laws of propagation of currents through
NT> the earth and the atmosphere.

The diagrams, footnotes, and patent references from pp12-18 alone
would be sufficient to convince you the error of your
implication. If that is not enough, then I would refer you to the
pp36-37 entries for mid-month, June 15-17, 1899. Tesla proceeds
to construct a system ground for the oscillator, followed by
electrical measurement of both the system ground and the water
pipe main supplying the lab. In later work all of the major earth
resonate frequencies were plotted with amazing accuracy. The
O'scope had to wait years to be invented. In the 1950's Schumann,
Bremmer, Budden, Wait, Galejs and other authors verified all of
Tesla's "ground" work step by step. See:

> Terrestrial Propagation of Long Electromagnetic Waves
J. Galeys, New York, Pergamon Press, 1972 

 DK> alley" and have repeatedly had to try to teach the lesson    
 DK> about the need for low-reactance paths to earth there -- 

 TS> "open land" ground electrodes, rods, screens, bonded         
 TS> radials, etc. 

I knew we would agree somewhere. I have been stating this here
for a year now.

 TS> If Richard, or anyone cares to comment. What have Tesla      
 TS> experimenters used for ground references?

Me not comment? Well I can't speak for everone, but I have listed
references above that you would obviously find informative. 

 TS> For those larger coils, I would suspect an array of radials  
 TS> using a few miles of #10 soft drawn Cu, with Erico
 TS> welded mesh for about 50' in the center, bonded with 4"      
 TS> strap, might be adequate in most places.  Add a couple of    
 TS> 30' chemical grounding electrodes in poor soil areas. Does   
 TS> anyone bother in high voltage experiments?   

I ground my stuff to a buried hydraulic lift. The lift assembly
consists of a large buried oil tank, air tank, supply and control
plumbing, and the actual steel piston assembly. Run from this
ground point (which is all metal spread out over 225 square feet)
are two 1" ground straps; one strap runs to connect buried
decorative pond (1500 gallon galvinized steel tank), the second
runs to a 50' length of 14" wide aluminum flashing submerged in a
nearby creek bed. 

All coil connections to this ground are 15' feet or less for the
high powered stuff. I use the equivalent of a 2-1/2" grounding
strap from the base of the coil, and the safety gap center post,
to the lift control plumbing (both copper and galvinized steel
pipe) where it enters the ground.

While the grounding system you document would be ideal, mine
functions. I do have some idea of what I am doing. I have also
done extensive experimentation on coil systems and their
grounding requirements. I have followed Tesla's footsteps
carefully in many respects. 

ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Date: 06-24-94  16:54
  From: Richard Quick                              
    To: Roy J. Tellason                           
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
Talking about coil construction...

 RQ> Get some rigid Plexi, Lexan, or polystyrene pipe/tubing with 
 RQ> a thin wall. 

 RJT> They used a cardboard tube for this,  a readily available   
 RJT> item,

PVC thin wall plastic "drain" pipe that has been sanded and
sealed is generally better than cardboard.

 RJT> but I'm sure that a lot of the other materials you mention  
 RJT> weren't around in those days.

No modern materials were not around, but this does not mean they
should not be used. Older coils were plagued with low efficiency
and unreliable operation. Many "classic" coils and projects of
this nature were full of errors and misconceptions. With modern
materials (and designs and schematics that utilize them) at my
fingertips I would never look back. 

 RQ> Wind the wire on the coil form.

 RJT> Is there any easy way to do this?       :-)

I set up a spindle through the center of the coil form, and roll
the form with one hand while feeding wire with other.

 RJT> That article referred to wooden disks in each end of the    
 RJT> form,..., 

 RQ> I cap the top and bottom of the coil form with disks of      
 RQ> plexiglass bedded in epoxy.

 RJT> What do you mean "bedded in epoxy"?

I mean smear a thick enough bead of epoxy on the cap and the end
of the coil form so that the epoxy is forced out when the parts
are fitted.


ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Date: 06-26-94  16:47
  From: Richard Quick               
    To: Don Kimberlin                     
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
... Still talking Tesla Coils...and inductive coupling.

 RQ> Yes. A Tesla coil is a resonate transformer. The
 RQ> "transformer"part means that the system involves energy
 RQ> exchange by induction. But it is not simply producing a
 RQ> "maximum induction field", but of producing a field of
 RQ> proper intensity and shape around a resonate inductive
 RQ> structure (coil).

 DK> ...OK, that sounds like there is concern for somehow
 DK> "shaping" the induction field around a core, rather than
 DK> merely letting it assume some random proportions, and
 DK> attempting to couple to it. Or am I zooming off on a
 DK> tangent?

No your shooting dead bullseyes. Field shaping is done primarily
by altering the coil geometries. Both primary and secondary coils
are juggled until good inductive coupling is secured. The form-
ation of a small compact field; even in intensity and sweeping
the secondary winding from the bottom turn to the top; usually
allows the most efficient transfer of energy between two coils.

... Then talking about...

 DK> ... the first "radio" people..

 RQ>Bahh, Marconi worked for Tesla for nearly a year, before
 RQ>1891, and stole a lot of technique, not to mention nine key
 RQ>patents. I am adverse to crediting thieves.

 DK> ...Now, THAT's interesting to me!  So Marconi hung around
 DK> Tesla, eh?  All the histories I've read seem to make no
 DK> mention of any connection between them.

 DK>.I *must* get into a Tesla history book one of these days!

How about US legal history. The United States Supreme Court
overturned Marconi & Co. radio patents in 1943 after testimony
and US Patent Office records showed clear priorities. It was
proven that Marconi had had access to Tesla's early work and then
went on to commercialization with that information.

... talking about grounds as a...

DK> ...low-reactance interface to earth.

 RQ>Tesla was the first to apply ground to a tuned circuit...

 DK> <Hertz> balanced and floating above ground, then Marconi
 DK> tying "radio" to ground. Certainly makes sense that Tesla
 DK> conceived of that change to use the earth for one side of
 DK> the circuit...

 DK> <I> repeatedly try to teach the lesson about <Lightning
 DK> Alley> the need for low-reactance paths to earth--

 RQ>... it seems no ground used for lightning can be too heavy.

 DK> <SET JOHN_WAYNE.SYS>... yuh got that right, Pilgrim.

 DK> <the> concept that the earth does not have unlimited ability
 DK> to conduct electricity away from a point contact.  Oh,
 DK> electric power engineers know this, but the general public..

What about earth resonate (electrically conducted) frequencies?

... talking about Tesla's extra coil...

 RQ>The third coil is not inductively coupled to the primary/
 RQ>secondary...<it is an> uncoupled resonator which is base fed
 RQ>by transmission line....<it> is allowed to resonate freely,
 RQ>unrestricted by the inductive coupling between primary and
 RQ>secondary... I believe three coil designs are possible that
 RQ>are as high as 95% efficient.

 DK> ...Sure seems like that would have an effective use in radio
 DK> transmitters.  Ever hear of anyone doing it there? They do
 DK> work to achieve the highest energy transfer, but to my
 DK> experience, only with a single primary and secondary....

You would have to talk to a radio engineer, but the principal of
resonance was discovered by Tesla. Tesla believed that large
resonate transformers offered the key to worldwide xmission of
commercial scale electrical power without wires.

If you electrically examine the system output, the secondary (or
"driver") coil in the three coil magnifier is simply the
secondary on a resonate transformer. The extra coil and earth
(the top and bottom connections to the secondary driver coil) are
acting as end resonators. Tesla to his patent attorneys clearly
stated he had discovered, and operated his equipment modulated
to, earth resonate frequencies below 30,000 Hz.

Looking at the oscillator as a whole, the current flow from the
air terminal was small. Tesla operated at very high voltage, but
retarded spark breakout when working with CW xmitters. The system
is very easily converted to spark production, as witnessed by the
publicity spark photos Tesla took of the Colorado Springs
Machine.
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Date: 06-24-94  23:10
  From: Don Kimberlin                           
    To: Terry Smith                             
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
TS> DK> ...My own background in high-powered radio (and Terry
TS> DK> Smith's,

TS>Nah...  I've never played with the stuff over 60 KW.

...That ought to be big enough to impress a CB-er, I'd say...

DK> btw) have taught us both about the important of a low- 
DK> reactance interface to earth. I grew up down in Florida's
DK> "lightning alley"

TS>From this thread, I'm getting an impression that broadcasters
TS>do a little more in the way of operating impedance calc-
TS> ulations and measurements, and projected ground related base
TS>losses, than folks who stare in awe at man made lightning. On
TS>a broadcast tower, with a 30 ohm self impedance, but a 10 ohm
TS>operating impedance in an array, a resistance to earth (half
TS>the radiator, as well as the coupling plane) of 3 ohms, when 1
TS>ohm is practical, makes a big difference.

...As my post indicated, it seems a very small proportion of the
population has any notion that the earth is not an unlimited and
quite good, uniform conductor.  Conversely, we sometimes seem
those who get badly hurt and wonder why when they disconnect the
electric power grounding wire from the stake outside in order to
paint their house...

TS quoting Don Kimberlin
DK> I have repeatedly had to try to teach the lesson about the
DK> need for low-reactance paths to earth there -- seen people
DK> lose literally millions of dollars worth of electronics and
DK> electrical hardware, plus unmeasurable amounts of business
DK> production for trying to ignore it in that part of the
DK> country.

TS>Have you ever seen anyone explode a concrete building floor
TS>slab? That's one I've only heard of, where someone had the
TS>brilliant idea of using reinforcing mesh in the slab as a
TS>cheap alternative to normal "open land" ground electrodes,
TS>rods, screens, bonded radials, etc.

...Seen it happen in Florida when insufficient attention is paid
to bonding the rebars in the poured floors, but then tying parts
of them to the RF ground screen.  You have to bond those puppies
all around when you're going to get the huge ground potential
rise from hits on a tower 50 feet away.  I try to get people to
envision a massive electrical wave radiating outward from the
discharge point, much like being in a canoe and tossing a huge
boulder overboard.  The canoeist usually gets swamped...


TS>Up these parts, we get winter.  Down your way, I guess you're
TS>more likely to see a glass encapsulated (and therefore
TS>insulated) ground rod, from lightning melting the quartz sand
TS>around the rod?

...Happens occasionally, but the larger hazard is a buildup of
non-conductive salts on the rod, then when there is a hit, the
rod conducts little or nothing, so the lightning goes elsewhere
and wreaks havoc.  If you can imagine it, one actually needs to
pull ground rods and "maintain" them in many locations.  Some
recommend doing that every two years, but most don't do anything
till they have a problem, and get away with 10 years or more...

TS>If Richard, or anyone cares to comment, what have Tesla
TS>experimenters used for ground references?  For those larger
TS>coils, I would suspect an array of radials using a few miles
TS>of #10 soft drawn Cu, with Erico welded mesh for about 50' in
TS>the center, bonded with 4" strap, might be adequate in most
TS>places.  Add a couple of 30' chemical grounding electrodes in
TS>poor soil areas.  Does anyone bother in high voltage
TS>experiments?

...Why sure, they all put in the FCC-standard 120 radials of 1/4
wavelength each at 60 Hertz!  (heheheee...nobody has that kind of
money!) Concord,N.C. (704)792-9241  (1:379/37)

ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Date: 06-27-94  21:22
  From: Richard Quick                            
    To: Don Kimberlin                            
  Subj: Tesla Coils
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

 -=> Sez Don Kimberlin to Richard Quick, about extra coils <=-

 DK> ...Sure seems like that would have an effective use in radio
 DK> transmitters.  Ever hear of anyone doing it there?  They do  
 DK> work to achieve the highest energy transfer, but to my       
 DK> experience, only with a single primary and secondary....

I should point out that Tesla fully intended his system to xmit
communications AND electric power. He had motor/alternator sets
which converted low frequency current (line power) into high
frequency multiphase CW current. When tuned and transmitting, the
extra coil was connected to the base of a large antenna. The
power supplies were patented by 1893, all of the oscillator/
antenna circuits (with explicit earth ground requirements)
patents were in place by 1897. I should stop here and state that
the US patent office repeatedly turned Tesla down for patents on
wireless power transmission system.... A patent office official
was then given an explaination and demonstration of the system by
Tesla in person, and a patent was immediately granted. He was
operating the "Magnifing Transmitter" at 250 KVA by 1900. 

Tesla also had a custom Westinghouse high voltage transformer at
Colorado Springs, and rotary spark gaps for disruptive operation.
The extra coil was disconnected from the antenna, air gaps were
placed in the primary, and the system was retuned for spark.
The famous spark photos were taken mainly for publicity, when the
coil was xmitting there was noting to see. But the spark photos
do show his tuning, his power levels, and his understanding of
harmonics. Sparks were not on the list of priority researches to
be investigated.

Tesla also used the coils as tuned antennas\receivers. Using 
coherers, relays, bulbs, etc., as indicators, Tesla was able to
detect far off lightning strikes (300 miles), and it appears,
pulsars, with his 45 foot diameter "radio telescope" setup. 

None of this work, or any of the patents issued to Tesla, can be
dismissed trivially. 

ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Date: 06-24-94  14:56
  From: Terry Smith                               
    To: Richard Quick                             
  Subj: 10KVA Tesla Coil
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
 TS> Back to the technology, do you know enough about the
 TS> time/frequency/power/conducted-induced-radiated signal
 TS> relationships to answer the questions previously on the
 TS> table, or to compare them for various coil designs, with and
 TS> without the third tuning coil?

 RQ> Absolutely, where did you think I get my numbers? Make them
 RQ> up? Too many people here have see how I document my work.    
 RQ> You are

I've noticed you've taken pains to document several aspects of
your work well, and that made me curious if you've tested other
parameters which have either not been mentioned, or which I've
failed to notice discussed here.  In arcing resonant circuits,
how closely does output track input?  (Input, I assume, is safer
and easier to monitor directly?)  Outside of commercial
environments, few people are equipped to monitor induced and
radiated fields quanitatively.  I was hoping you'd know of such
studies by someone, if not equipped to measure that aspect of
large coil operation yourself.  (Impress me... Are you?)  

As Don pointed out, your endeavors have great similarities, as
well as major differences, to systems on which he or I have
worked.  Even in commercial situations, there are frequently
pieces of test equipment which would be useful, but not in the
budget.  

 TS> Obviously it's a time/energy relationship which allows
 TS> describing a single coil as 10 KVA, and also as 2 megawatts
 TS> peak output.

 RQ> Very good. Go to the head of the class.  

Sorry for any confusion.  Power levels have been mentioned at
times out of context, in a thread lengthy enough so that it takes
some sorting to keep track of peak versus average aspects of the
discussion.  RADAR would be the obvious model for time/energy
relationship spec comparisons, but controlled to rather precise
tolerances compared to what I'd guess you see in arcs?  

 TS> As to the 6.78 MHz or other ISM frequencies, I strongly
 TS> suspect that imitation lightning is inherently too wideband
 RQ>      ^^^^^^^
 TS> to possibly be confined to such allocated legal spectrum.

 RQ> BTW, where did you come up with this frequency???

47CFR18.301  (FCC ISM Regs, where unlicensed signal strengths are
conditionally unlimitted)  Doesn't everyone have a copy on the
bookshelf by their computer?  <g>  That's the lowest of the
available frequencies of that type, and one with a usable
harmonic also.  

If emmisions could be confined to a narrow bandwidth, the need to
suppress signal transmission could be made moot.  I know you've
discussed resonant versus "brute force" circuits.  On the other
hand, arcing tends to involve a wide frequency domain, due to
variable equivalent waveforms during rapid rise and fall.  I
would presume the former could not be used to control bandwidth
due to the latter.  Do your experiments confirm this, or are
there any interesting tricks by which it's possible to regulate
the effective frequency of an arc rather narrowly?  


 TS> Quite frankly, I'm amazed that megawatt surges haven't
 TS> caused neighbors problems.

 RQ> I am sorry to disappoint you. I have expended time and
 RQ> effort to ensure I am not a causing a problem.

I've noticed in other posts discussion of coils large enough to
need a 60x80x50 foot bonded steel structure to house but suppress
the output of some coils.  This would be beyond what's available
to hobbiests without unusual means, and I have noticed emphasis
at times on avoiding the cost of commercial vacuum or G type mica
capacitors.  If you've conducted the operations described here,
and suppressed both RF complaints and regulatory violations, I'm
impressed, rather than disappointed.  An old barn, or the back
yard on a nice weekend afternoon, would be more in line with what
I'd expect of a test site for anyone other than a career
technologist, like Tesla.  

What special steps have you taken to avoid RFI problems with
neighbors?  Is there something I'm overlooking about the nature
of the output of these coils which makes the radiated output
couple so inefficiently to the earth that RFI is less severe than
from other forms of high power arcs?  

BTW, the Origin line is one of several I've been rotating since
well before this thread started.  Terry
 ! Origin: Charges filed under Ohms Law!  (203)732-0575 BBS
(1:141/1275)

ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Date: 06-24-94  22:21
  From: Brian Thurston                           
    To: Richard Quick                             
  Subj: TESLA
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
Hi Richard:

A very concise and succinct statement of the events concerning
Tesla and his AC transmission systems.

My only additional fact is that Tesla died pennyless in Canada
still trying to develop his wireless energy transmission system
into a commercial product. Regards, Brian.

 White Rock, BC, Canada (1:153/915)

ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Date: 06-26-94  09:30
  From: Michaelj Scott                          
    To: Richard Quick                            
  Subj: TESLA COILS, VIDEO
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
MJS responding on 26Jun1994 to RQ's 14Jun1994:

>Mike,
>Thanks for the nice letter. Your video tape was posted this
>morning,you should receive it shortly after you get this post.

Both probably arrived the same time, but I'm two weeks behind on
reading.  I download a couple of times per week for the echoes
that interest me, but I only get to read them on Sunday.

>I included a disk with many related text files. It should make
>for some interesting reading, as the archived material goes back
>over six months.

I've only had time to watch it once, late at night with my wife.
She was much more interested in the old cars than in "that giant
sparking thing".  Richard, the video does a great job of getting
the thrill of seeing a monster Tesla coil venting angrily at the
world.  The sound effects were something of a surprise.  We
loved watching the experiments progress; the raising of coil, the
cleaning of the garage, moving the whole apparatus outside.  All
of this over several days (weeks?) lets us get a sense of the
enormity of the project and the attention to detail.

I think I've been following this echo for about 6 months, maybe a
little longer.  I haven't had time to look at the floppy, but
I'll get to it soon.  As I mentioned, I'll likely not be building
a Tesla coil, but the pictures to go along with this lively
reading are a must have for anyone who has been following the
Tesla coil threads.

>If you have any problems, questions, comments, corrections,
>etc., please post me. Do let me know that you have received your
>video, and let us know what you think.

As a mere electronic engineer, I don't think that I'm qualified
to offer any corrections to the high powered lash-ups that you
have concocted.  The only time I had to deal much with coils or
transformers, was once with a "magnetic amplifier" that
controlled a motor to the vanes and thereby regulated the
temperature in a jet engine.  It used diodes and resistors to
saturate transformer cores and hence used current from one
circuit to control much larger current in another without
transistors or tubes.  It was very reliable, nearly vibration
proof, operated from 80 below to 300 above zero, and would work
submerged in water.  No sparking or arcing though.

I look forward to sharing this with my co-workers.  We need to
get a TV and VCR up to work, since I do not want this tape to get
"borrowed" like other lost tapes.

The early part of the tape suffers a little from an unsteady hand
but does get the point across nicely.  Some of the close-ups
weren't.

I was concerned that you or an onlooker might be hurt by an
errant spark.  Sparks as big around as a beer can, leaving large
black marks on your driveway seems equivalent to playing outside
in a Texas lightning storm.

Thanks for the wonderful video tape.  It's the best thing I've
seen on the TV in quite a while, although my wife would debate
that opinion.

You will likely get some response from some other Michael Scott
claiming that he never heard of you.  There are more than 10 of
me and my clones running around here in the Sacramento area.
I've appended a "J" to my Christian name in an effort to
distinguish myself from the other imposters.

Regards, Mike in Folsom, Calif.  (916) 448-2483 (1:203/52)

ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Date: 06-28-94  13:41
  From: Dave Halliday                          
    To: Richard Quick                               
  Subj: Tesla Coils
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Hi Richard

Just dropping a note to let you know that I am still incredibly
busy at the store but I plan to have the coil up and running in
about a month or so.

I finally broke down and hired another full-time person so I can
go back to "normal" 8-10 hour days...  sheesh...

Also, I was wondering about the current regulation going into the
pole pig - you are using an arc welder.  I have several baseboard
heaters and I was thinking of paralleling a couple of those -
lossy but hey!

The work on the controller is going well - I have not hooked it
up to the variacs yet - it's still at the store but it works
well.  I had done some other projects using that CPU so I still
had some development boards left. (206) 528-1941  (1:343/210)