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  Date: 06-01-94  17:15
  From: Richard Quick                 
    To: Bruce Ratcliffe               
  Subj: electronics project ideas

 AS| Does anyone have any suggestions as to where I could find
 AS| plans or a book on building a small tesla coil? ...
 AS| (not a) monster, just a small scale coil that would make a
 AS| good summer project.

DH> Hi Andrew - I don't know of any books that give hands-on
DH> construction plans but there are several people here who
DH> are active. I friend of mine is building a "tabletop" coil
DH> 3" diameter, 12" long...

DH> You will need to collect some neon sign transformers
DH> (12-15Kv), build a spark gap, put together a capacitor and
DH> wind the primary and secondary coil.

I just passed this along if you are interested.

                                     R.Q.


  Date: 06-03-94  17:52
  From: Richard Quick          
    To: Andrew Sempere          
  Subj: 10KVA Tesla Coil

You were posting this to Blair Groves, but I finally succumbed..

 AS> (hence the burning of fossil fuels that destroy the ozone
 AS> layer)

From what I have read it is chloroflorocarbons that have been
firmly identified as responsible for atmospheric ozone depletion,
products such as "freon" used in the chillers of air conditioning
systems and propelents in spray cans.

 AS> I heard that Tesla himself build a 10 story coil that was
 AS> capable of lighting up bulbs 20 miles away....

The tower of the Wardenclyffe commercial plant built in 1901 was
167 feet tall (air terminal) on a stone and concrete foundation
that exended 50 feet below the water table (the ground terminal).
The power station built near the tower had footings poured for
four massive multi-phase generators to drive what at the time was
the largest capacitor bank in the world. The coil was steam
powered, with one boiler and generator operational.

 AS> ... (the coil) caused all the corn fields within a 20 mile
 AS> radius to spontaneously combust :)   -Andrew

Nothing like this ever occured, though many of the effects of his
oscillators were even stranger. He experimented with mechanical,
and electromechanical, oscillators in addition to the purely
electrical devices such as the Tesla coil.


  Date: 06-01-94  06:48
  From: Bob Patten                        
    To: Andrew Sempere                     
  Subj: Tesla Coils

AS> Does anyone have any suggestions as to where I could find
AS> plans or a book on building a small tesla coil? (Is this a
AS> stupid question?) I really don't want a monster, just a small
AS> scale coil that would make a good summer project.  

How about an ignition coil using a K-Mart universal coil (abt
$12) and a 555 timer chip?  Makes about 40KV, easy to build, and
cheap.  For an S.A.S.E., can copy the book and send it to you.
        Bob Patten
        2841 N.W. 112 Terrace
        Plantation, Fl. 33323

 ! Origin: Bashful Pervert BBS  (305) 472-7715  (1:369/120)


  Date: 06-02-94  07:10
  From: Bob Patten                          
    To: All                                  
  Subj: Tesla Coils

I'm interested in building a Tesla coil using a ham transmitter
as the power source (if it's possible).  The lowest frequency
available to me is 1.8Mhz at 100w or 3.5Mhz at 1000w, both at an
impedance of 50 ohms.

I know that the conventional Tesla coils with spark gaps operate
at much lower frequencies.  Does anyone have any experience in
this area?

! Origin: Bashful Pervert BBS  (305) 472-7715 (1:369/120)


  Date: 06-03-94  00:17
  From: Michael Diresta                    
    To: Richard Quick                      
  Subj: Tesla Coils

Richard, hope it's ok to jump in. Many years ago (30) I built a
Tesla Coil for a school project. The unit got packed up and put
away. After seeing so many messages here it renewed my interest.
I unpacked it and although it looks perfect it don't work. I
never saved the schemetic and haven't a clue where to find one. I
do remember that it came out of a Popular Science/Mech mag back
in the  60's. The unit has from memory a 30" coil of # 32 wire
that I wound by hand on a wooden Dowel. There a big transformer,
can't remember where I found it and a smaller 6.3V transformer
used to run two 611A tubes. There are also a couple of barrel
type caps that I got from an old B/W TV set, a couple of switches
one of each transformer and a few other parts. Have you any ideas
where I should start??

 ! Origin: AEOLUS - Andover, MA, USA - (508) 474-0328 (1:324/114)


  Date: 06-03-94  11:15
  From: Andrew Sempere             
    To: Bob Patten                     
  Subj: Tesla Coils

  >monster, just a small scale coil that would make a 
  >good summer project.  

 BP> How about an ignition coil using a K-Mart universal coil
 BP> (abt $12) and a 555 timer chip?  Makes about 40KV, easy to   
 BP> build, and cheap. For an S.A.S.E., can copy the book and     
 BP> send it to you.
 BP>         Bob Patten
 BP>         2841 N.W. 112 Terrace

Great! I'll send you an SASE ASAP  Thanks! -Andrew

 ! Origin: AEOLUS - Andover, MA, USA - (508) 474-0328 (1:324/114)


  Date: 06-03-94  11:29
  From: Dave Halliday            
    To: Andrew Sempere                 
  Subj: Tesla Coils

 DH> I friend of mine is building a "tabletop" coil - 3"
 DH> diameter, 12" long. You will need to collect some neon sign  
 DH> transformers (12-15Kv), build a spark gap, put together a    
 DH> capacitor and wind the primary and secondary coil.  Key      
 DH> thing with coils - stay away from PVC pipe 

 AS |Thanks for the help, a 3 X 12 sounds like a good size...

Hi Andrew - I saw that Richard QUick also responded to your
question - he has a lot of great information that he has posted.

I was initially interested in Tesla Coils back when I was in High
School and built one along the "classical" lines and was very
disappointed with the results.  The "classical" school of thought
then was to go for a long skinny secondary, just a few turns on
the primary and a large capacitance.  This turns out to be 150%
wrong!  You need a short squat secondary, about 5-15 turns and a
smaller capacitance for optimal performance. 

The secondary should be about 1:4 ratio dia to height.

 ! Origin: Grey Matter * Seattle, WA * (206) 528-1941 (1:343/210)


  Date: 06-03-94  18:37
  From: Roy J. Tellason                    
    To: Andrew Sempere                     
  Subj: Tesla Coils

30 May 94, Andrew Sempere writes to All:

 AS> Does anyone have any suggestions as to where I could find
 AS> plans or a book on building a small tesla coil? (Is this a   
 AS> stupid question?) I really don't want a monster, just a      
 AS> small scale coil that would make a good summer project.

Some years ago there were a couple of articles published on this
in Popular Electronics.  One was about 3 or 4 feet tall,  and 
would generate anywhere from 250,000-750,000 volts depending on 
how many glass-plate capacitors you added to it.  The other was a 
somewhat smaller unit which sounds like it would be what you're 
looking for.

If anyone out there has a copy of this magazine,  I'd sure love
to get copies of the articles again,  I lost my copy of it years 
ago...

That big one would light a flourescent tube 6 feet away with no
wires! <grin>
 
 ! Origin: TANSTAAFL BBS (1:270/615)

  Date: 06-05-94  00:24
  From: Andrew Sempere                                  
    To: Richard Quick                                
  Subj: 10KVA TESLA COIL

* Original From: Norman Cardillo (1:324/114)
* Original To  : Andrew Sempere (1:324/114)

Somebody once said that power should be transmitted with Tesla
Coils instead of using wires, because those wires running every-
where cause a health problem. This would probably cause more 
problems than transmission lines.
 
 ! Origin: AEOLUS - Andover, MA, USA - (508) 474-0328 (1:324/114)


  Date: 06-04-94  00:37
  From: Terry Smith                               
  To: Bob Patten                                  
  Subj: Tesla Coils

BP> I'm interested in building a Tesla coil using a ham
BP> transmitter as the power source (if it's possible).  
BP> The lowest frequency available to me is 1.8Mhz at 100w 
BP> or 3.5Mhz at 1000w, both at an impedance of 50 ohms.
BP> I know that the conventional Tesla coils with spark gaps
BP> operate at much lower frequencies.  Does anyone have any 
BP> experience in this area?

You could quite easily turn a Tesla coil into a transmitter,
generating signal types not approved for HAM use, at strengths 
well above Part 15 limits.  Below 9 kHz such limits would not 
apply.  

Other than by only operating it well inside the boundaries of a
BIG piece of private property, I wonder what kind of induced 
and radiated signal strenghts are produced by large Tesla coils.  
I'd guess that what sounds like a 50 KVA unit discussed here 
probably substantially exceeds Part 15 unintentional radiator 
emmissions limits.  

If Richard, or the others playing with toys, notice...  
Over what range of frequencies are you guys producing emmissions, 
and at what kind of field/distance?  I'd imagine some coils 
produce an unstable (in terms of frequency) output over a 10 or 
100 to 1  range, while others may be stable within 5% or less.  
Is this a reasonable presumption?  

Have any of these coils been monitored with field strength
meters, or spectrum analyzers with calibrated antenna sets?  

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

  Date: 06-05-94  00:26
  From: Andrew Sempere                          
    To: Dave Halliday                              
  Subj: Tesla Coils

DH> I was initially interested in Tesla Coils back when I was in
DH> High School Sounds like me... I always thought I was the only 
DH> high school kid who thought that building a tesla coil might 
DH> be fun... Oh well :)

DH> and built one along the "classical" lines and was very
DH> disappointed with the results.  The "classical" school 
DH> of thought then was to go for a long skinny secondary, 
DH> just a few turns on the primary and a large capacitance.  
DH> This turns out to be 150% wrong!  You need a short squat
DH> secondary, about 5-15 turns and a smaller capacitance for
DH> optimal performance.

 DH> The secondary should be about 1:4 ratio dia to height.

Thanks for the tips, as I am entirely new to Tesla coils,
anything is helpful, this promises to be quite interesting... 
-Andrew
 
 ! Origin: AEOLUS - Andover, MA, USA - (508) 474-0328 (1:324/114)


  Date: 06-05-94  00:29
  From: Andrew Sempere                              
    To: Roy J. Tellason                            
  Subj: Tesla Coils

 RJT> Some years ago there were a couple of articles 
 RJT> published on this in Popular Electronics.  One was 
 RJT> about 3 or 4 feet tall,  and would generate anywhere 
 RJT> from 250,000-750,000 volts depending on how many glass-
 RJT> plate capacitors you added to it.  The other was a 
 RJT> somewhat smaller unit which sounds like it would be 
 RJT> my copy of it years ago...

I think I'm going to check my local library, they offer a service
that can fax a copy of almost any article you want for a small 
charge, I used it to get a few other old Popular Electronics 
articles. If I find it I'll let you know (If you want a copy just 
let me know) Anyway, thanks for the note  -Andrew  

 RJT> That big one would light a flourescent tube 6 feet away
 RJT> with no wires! <grin>

 Cool! 8-)
 
 ! Origin: AEOLUS - Andover, MA, USA - (508) 474-0328 (1:324/114)


  Date: 06-06-94  18:25
  From: Richard Quick                            
    To: Bob Patten                         
  Subj: Tesla Coils

-=> Sez Bob Patten to All <=-

 BP> I'm interested in building a Tesla coil using a ham
 BP> transmitter as the power source (if it's possible).

There are at least two ways that I can think of to run a coil
from a driver such as this. But I would not advise doing it.
The ham equipment, powerful as it is, is not designed to drive
a coil to spark.

You would be better (and it would be much safer for the HAM
xmittr) to design a tube driven or spark gap excited tank circuit
to drive a coil.


  Date: 06-06-94  18:25
  From: Richard Quick                              
    To: Michael Diresta                              
  Subj: Tesla Coils

-=> Sez Michael Diresta to Richard Quick <=-

 MD> Richard, hope it's ok to jump in.

We love to jump in!

 MD> Many years ago (30) I built a Tesla Coil for a school
 MD> project. The unit got packed up and put away. After
 MD> seeing so many messages here it renewed my interest. I
 MD> unpacked it and although it looks perfect it don't work. I
 MD> never saved the schemetic and haven't a clue where to find
 MD> one. I do remember that it came out of a Popular
 MD> Science/Mech mag back in the  60's. The unit has from memory
 MD> a 30" coil of # 32 wire that I wound by hand on a wooden
 MD> Dowel. There a big transformer, can't remember where I found
 MD> it and a smaller 6.3V transformer used to run two 611A
 MD> tubes. There are also a couple of barrel type caps that I
 MD> got from an old B/W TV set, a couple of switches one of each
 MD> transformer and a few other parts. Have you any ideas where
 MD> I should start??

I will start by telling you that I am not an expert on tube
coils; though I am familiar with them, I have never designed or
built one. With that out of the way, I will let you know what I
can, and reference the rest.

Most likely the project you are looking at was titled "Lil' Tesla
Coil",(or somesuch), and was built by a lot of Popular Science
readers of the era. The design is so dated by modern standards
that I would scavenge the tubes, caps, and power supply; the rest
I would scrap and rebuild. The reasons for this are nearly too
numerious to list...

1) Wood is at the bottom of the list of suitable coil form
   materials. This coil should be wound on acrylic, polyethylene,
   polystyrene, polypropylene, or some other high Q plastic.

2) The wire (#32) is too thin for excellent efficiency. Move up
   to #24, or larger, double Formvar covered magnet wire.

3) The coil form is too skinny; it needs to be fatter for a
   higher inductance, higher Q coil, using the heavier wire. The
   new plastic secondary coil should have an aspect ratio (height
   to width ratio) of no more than 4:1, 3:1 being close to ideal.

4) The primaries need to be rebuilt to match the new higher Q
   secondary design. Greater surface area conductors (thin wall
   pipe, coax shield, strap, strip, etc.) should be substituted
   for the solid bare copper wire typically used on early tube
   coils.

By far and away the most exhaustive reference on tube circuits
was done by James and Kenneth Corum and is titled "VACUUM TUBE
TESLA COILS", published by Corum & Assoc, 8551 State Route 534,
Windsor, Oh. 44099, available from the International Tesla
Society, P.O. Box 5636, Colorado Springs, CO. 80931.

A second book that features what I believe is the same or similar
coil is "Tesla Coils! 100 Years of Electrical Magic" by Brent
Turner, and most likely available at the address above. Mr.
Turner's book has a lot of info on the solid state drivers for
inductively coupled Tesla coils. His coil is a historical
reproduction of the tube coils popularized in the 60's.

Harry Goldman at The Tesla Coil Builders Association will have
additional book sources: TCBA, 3 AMY LANE, QUEENSBURY, NEW YORK
12804.   (Tell him I refered you)

This will get you started, if you need any more help please let
me know.


  Date: 06-06-94  23:34
  From: Andrew Sempere                                
    To: Richard Quick                              
  Subj: 10KVA Tesla Coil

RQ> From what I have read it is chloroflorocarbons that have
RQ> been firmly identified as responsible for atmospheric ozone
RQ> depletion, products such as "freon" used in the chillers of 
RQ> air conditioning systems and propelents in spray cans.

I suppose that I really was rolling two issues together: Ozone
depletion and global warming.  One of the biggest "greenhouse 
gasses" is carbon dioxide, a result of combustion, while the 
ozone aspect is mainly the result of CFC's...

 RQ> The tower of the Wardenclyffe commercial plant built in 1901
 RQ> was 167 feet tall (air terminal) on a stone and concrete
 RQ> foundation that exended 50 feet below the water table (the 
 RQ> ground terminal).

Wow :) Sounds like a very large, very expensive project. 
Incidentally, was it ever operational?

 AS> ... (the coil) caused all the corn fields within a 20 mile
 AS> radius to spontaneously combust :)   -Andrew

 RQ> Nothing like this ever occured, though many of the effects
 RQ> of his oscillators were even stranger. He experimented with
 RQ> mechanical, and electromechanical, oscillators in addition 
 RQ> to the purely electrical devices such as the Tesla coil.

Too Bad... I heard the story at an electricity demonstration
using a three story Van de Graph generator, a tesla coil, and 
a few other devices at the Boston Museum of Science.  While I 
had my doubts, the image of exploding cornfields amused me... 
Oh Well... -Andrew

 ! Origin: AEOLUS - Andover, MA, USA - (508) 474-0328 (1:324/114)

  Date: 06-06-94  19:36
  From: Richard Quick                                
    To: Terry Smith                              
  Subj: Tesla Coils

-=> Sez Bob Patten <=-

 BP> I'm interested in building a Tesla coil using a ham
 BP> transmitter as the power source (if it's possible).
 BP> The lowest frequency available to me is 1.8Mhz at 100w or
 BP> 3.5Mhz at 1000w, both at an impedance of 50 ohms.
 BP> I know that the conventional Tesla coils with spark gaps
 BP> operate at much lower frequencies.  Does anyone have any
 BP> experience in this area?

 -=> Sez Terry Smith to Bob Patten <=-

 TS> You could quite easily turn a Tesla coil into a transmitter,
 TS> generating signal types not approved for HAM use, at
 TS> strengths well above Part 15 limits.  Below 9 kHz such
 TS> limits would not apply.

He wants to drive a coil with xmitr outputs, not set up a coil to
mimic xfrmr output (ie make a transmitting Tesla Coil). There is
a big difference in making a coil transmit, and making a
transmitter drive a coil to spark.

 TS> Other than by only operating it well inside the boundaries
 TS> of a BIG piece of private property, I wonder what kind of
 TS> induced and radiated signal strenghts are produced by large
 TS> Tesla coils.  I'd guess that what sounds like a 50 KVA unit
 TS> discussed here probably substantially exceeds Part 15
 TS> unintentional radiator emmissions limits.

The only large coil I have heard discussed here is mine, and it
is 10 KVA (where did 50 KVA come from anyway?) coil. As for
induced and radiated signal strengths... Oh there is some, I
won't deny it. Up close the field strength will damage modern
electronics. But my REAL emmissions are neglible, most everthing
I generate goes to ground.

 TS> If Richard, or the others playing with toys,
                                            ^^^^
I love this guy!

 TS> notice...  Over what range of frequencies are you guys
 TS> producing emmissions, and at what kind of field/distance?
 TS> I'd imagine some coils produce an unstable (in terms of n
 TS> frequency) output over a 10 or 100 to 1 range, while others
 TS> may be stable within 5% or less.  Is this a reasonable
 TS> presumption?

Uh, yeah I guess so...

 TS> Have any of these coils been monitored with field strength
 TS> meters, or spectrum analyzers with calibrated antenna sets?

Oh, man... You put a calibrated antenna set anywhere within 50-60
feet of one of my experiments and you are going to instantly fry
some real expensive equipment. Spectrum anyalizer??? I can
usually measure field strength with volt/ohm meter, and I
register on the volts scale, (not milivolts) with a resistor and
rectifier in the probe antenna. Better yet, just grab the closest
tube with any vacuum in it, does it glow bright? Yup, the coil is
firing.....

Of course, whether or not I am causing anybody any problem is
another, completely different, story. My equipment is responsibly
built and operated. I have had ZERO complaints about RFI, and I
have checked. My biggest complaint? My sparkgaps sound like
unmuffled chainsaws, and people complain about the noise...


  Date: 06-05-94  05:13
  From: Bob Patten                                
    To: Andrew Sempere                              
  Subj: Tesla Coils

-> BP> How about an ignition coil using a K-Mart universal coil
-> BP> Makes about 40KV, easy to build, and cheap.
-> BP> S.A.S.E., can copy the book and send it to you.
-> BP>         Bob Patten
-> BP>         2841 N.W. 112 Terrace

-> Great! I'll send you an SASE ASAP  Thanks! -Andrew

I think you'll have fun with it!  You can get all the other parts
at your local Radio Shlock and the whole project won't cost you a
ton of time or money...        73,       BP
 ! Origin: Bashful Pervert BBS  (305) 472-7715 (1:369/120)


  Date: 06-05-94  18:47
  From: Roy J. Tellason                            
    To: Bob Patten                                
  Subj: Tesla Coils

02 Jun 94, Bob Patten writes to All:

 BP> I'm interested in building a Tesla coil using a ham
 BP> transmitter as the power source (if it's possible).

Why would you want to do that?  TANSTAAFL BBS (1:270/615)


  Date: 06-05-94  19:16
  From: Roy J. Tellason                        
    To: Andrew Sempere                                   
  Subj: Tesla Coils

05 Jun 94, Andrew Sempere writes to Roy J. Tellason:

 RJT>> Some years ago there were a couple of articles published
 RJT>> on this in Popular Electronics.  One was about 3 or 4 feet 
 RJT>> tall,  and would generate anywhere from 250,000 -750,000 
 RJT>> volts depending on how many glass-plate capacitors you 
 RJT>> added to it.  The other was a somewhat smaller unit which
 RJT>> sounds like it would be my copy of it years ago...

 AS> I think I'm going to check my local library, they offer a
 AS> service that can fax a copy of almost any article you want 
 AS> for a small charge, I used it to get a few other old Popular 
 AS> Electronics articles. If I find it I'll let you know (If you 
 AS> want a copy just let me know).

Great!  Sorry I can't be more specific about what issue it was
in,  or even the year.  I'd say that the odds are pretty good 
that it was 1965 or earlier, if I had to take a guess.  Yeah,  
if you get this let me know what it amounts to and I'll get back 
to you about copies,  etc. ! Origin: TANSTAAFL BBS (1:270/615)


  Date: 06-06-94  02:41
  From: Bob Patten                                    
    To: Terry Smith                                 
  Subj: Tesla Coils

BP> I'm interested in building a Tesla coil using a ham
BP> transmitter power source (if it's possible).  The lowest 
BP> frequency available is 1.8Mhz at 100w or 3.5Mhz at 1000w, 
BP> both at an impedance of 50... I know that the conventional 
BP> Tesla coils with spark gaps operate lower frequencies.  
BP> Does anyone have any experience in this area

-> You could quite easily turn a Tesla coil into a transmitter,
-> generating <signal> types not approved for HAM use, at 
-> strengths well above Part 15 limits. Below 9 kHz such limits 
-> would not apply.

Well, in my case, I could always key it and make some CW QSO's
whilst demonstrating the effects of the Tesla coil.  I imagine it 
would radiate a clean CW signal...
 
 ! Origin: Bashful Pervert BBS  (305) 472-7715  (1:369/120)


  Date: 06-06-94  19:57
  From: Randy Dixon                                 
    To: Andrew Sempere                                    
  Subj: Tesla coils

I knew a Guy whom made one and lit up a guy 2 houses down whom
was using his telephone, so please be careful when testing 
these toys... Randy ! 1.58/004124 Pleasure Palace BBS
(1:3642/506)


  Date: 06-06-94  23:03
  From: Michael Diresta                            
    To: Andrew Sempere                             
  Subj: Tesla Coils

Hi, If you get the plans I'd like a copy. I built one years ago
and it not longer works and naturally I lost the plans. I love 
to see if I could get it running again. 
 
 ! Origin: AEOLUS - Andover, MA, USA - (508) 474-0328 (1:324/114)

  Date: 06-06-94  23:46
  From: Andrew Sempere                            
    To: Roy J. Tellason                     
  Subj: Tesla Coils

 RJT>> Popular Electronics.  One was about 3 or 4 feet tall,  
 RJT>> and would generate anywhere from 250,000-750,000 volts 
 RJT>> depending on how many glass-plate capacitors...

 RJT> Great!  Sorry I can't be more specific about what 
 RJT> issue it was in,  or even the year.  I'd say that the 
 RJT> odds are pretty good that it was 1965 or earlier,  if 
 RJT> I had to take a guess.  Yeah,  if you get this let me 

Well, I checked one database, and the only entry they had was 
for Radio Electronics, Sept '91, p33: "plans for construction 
of a solid state Tesla coil"  The issue was checked out so I 
didn't get a chance to look at it, although I don't think this 
is the same artical you are talking about... 
I'll keep looking and keep you posted... -Andrew

 ! Origin: AEOLUS - Andover, MA, USA - (508) 474-0328 (1:324/114)

  Date: 06-07-94  21:59
  From: Richard Quick                               
    To: Andrew Sempere                             
  Subj: 10KVA Tesla Coil

 RQ> The tower of the Wardenclyffe commercial plant built in 1901
 RQ> was 167 feet tall (air terminal) on a stone and concrete
 RQ> foundation that exended 50 feet below the water table (the
 RQ> ground terminal).

 AS> Wow :) Sounds like a very large, very expensive project.

Yes.

 AS> Incidentally, was it ever operational?

Briefly at reduced powers. The transmitter had it's own power
plant and shop. Tesla remarked in foreclosure hearings and
depositions relating to this work on the coal expense at
Wardenclyff. During depositions, he submitted photos of multi-
phase high speed generators weighing several tons...

"Reduced power" on the Wardenclyff machine would be around 250
KVA guesstimate. Note that this is not the Colorado Springs
machine which processed around 250 KVA when maXed.

 AS> ... (the coil) caused all the corn fields within a 20 mile
 AS> radius to spontaneously combust :)   -Andrew

 RQ> Nothing like this ever occured...

 AS> Too Bad... I heard the story at an electricity demonstration

Not that I am aware of anyway. There are some pretty wild
"eyewitness" reports of effects. Most people don't pay attention
to the solid evidence such as photographs, notes, court hearings,
etc., that document the size and power levels of his equipment.
The facts are so commonly distorted that what is popularized is
almost as damaging as what was left unsaid.

Tesla is the father of an entire age of man's history.

Long before lightning at Colorado Springs, Tesla had designed and
patented key aspects of the nations 60 cycle power grid. His work
with higher frequency electricity led him to key patents in
Radio, confirmed by the US Supreme Court in 1943. His list of
related diagrams and patents for mechanical, electro-mechanical
and electrical equipment leaves little to the imagination when
taken as a whole. His work was revolutionary.

Long before Marconi could send a "click" across the English
Channel; Tesla had equipment that was capable of sending and
receiving signals hundereds, if not thousands, of miles. As the
inventor of the first commercial alternating current power system
at Niagra Falls, now in use worldwide, he was quite familiar with
industrial scale operations. His work with the experimental
oscillator at Colorado Springs, and later the unfinished (but
operational) commerical plant on Long Island (Wardenclyff), were
his efforts to globally supply both information and energy
without wires. These plants required conventional (hydro, steam)
power supplies. No energy was "created" or "free". In the
Wardenclyff plant, the coal bill for operations was a stress on
Tesla's finances, and the plant later went into forclosure.

The major components of these systems were simple: Ground,
primary coil, secondary or "driver" coil, extra coil, air
terminal, and power supply components to drive the primary coil;
such as high voltage pulse discharging capacitors, step up xfmrs,
and primary spark gap or break device.

The principal of operation would take another post of this length
to cover in any detail, but suffice now to say that the ground
and air terminal currents were very very large. Side effects from
operation of the coil system at Colorado Springs were noted by
Tesla as well as others, and were frequently repeated. These
effects included; people reported drawing electrical arcs (not
static electricty) from water pipes to their bodies throughout
the town of Colorado Springs, insects took flight covered in St.
Elmo's Fire, horses were pulling electrical arcs (not static
electricity) from the ground to their shoes, local atmospheric
illumination (corona type effects) around the machine, etc..

Like I said, too much has been sensationalized, but the true
facts really strike home.


  Date: 06-03-94  17:52
  From: Richard Quick                              
    To: Andrew Sempere                               
  Subj: 10KVA Tesla Coil

You were posting this to Blair Groves, but I finally succumbed..

 AS> (hence the burning of fossil fuels that destroy the ozone
 AS> layer)

From what I have read it is chloroflorocarbons that have been
firmly identified as responsible for atmospheric ozone depletion,
products such as "freon" used in the chillers of air conditioning
systems and propelents in spray cans.

 AS> I heard that Tesla himself build a 10 story coil that was
 AS> capable of lighting up bulbs 20 miles away....

The tower of the Wardenclyffe commercial plant built in 1901 was
167 feet tall (air terminal) on a stone and concrete foundation
that exended 50 feet below the water table (the ground terminal).
The power station built near the tower had footings poured for
four massive multi-phase generators to drive what at the time was
the largest capacitor bank in the world. The coil was steam
powered, with one boiler and generator operational.

 AS> ... (the coil) caused all the corn fields within a 20 mile
 AS> radius to spontaneously combust :)   -Andrew

Nothing like this ever occured, though many of the effects of his
oscillators were even stranger. He experimented with mechanical,
and electromechanical, oscillators in addition to the purely
electrical devices such as the Tesla coil.


  Date: 06-05-94  00:24
  From: Andrew Sempere                                
    To: Richard Quick                               
  Subj: 10KVA TESLA COIL

* Original From: Norman Cardillo (1:324/114)
* Original To  : Andrew Sempere (1:324/114)

Somebody once said that power should be transmitted with Tesla
Coils instead of using wires, because those wires running every-
where cause a health problem. This would probably cause more 
problems than transmission lines.

 ! Origin: AEOLUS - Andover, MA, USA - (508) 474-0328 (1:324/114)


  Date: 06-06-94  18:25
  From: Richard Quick                                   
    To: Bob Patten                                 
  Subj: Tesla Coils

-=> Sez Bob Patten to All <=-

 BP> I'm interested in building a Tesla coil using a ham
 BP> transmitter as the power source (if it's possible).

There are at least two ways that I can think of to run a coil
from a driver such as this. But I would not advise doing it.
The ham equipment, powerful as it is, is not designed to drive
a coil to spark.

You would be better (and it would be much safer for the HAM
xmittr) to design a tube driven or spark gap excited tank circuit
to drive a coil.


  Date: 06-07-94  01:22
  From: Bob Patten                                   
    To: Roy J. Tellason                          
  Subj: Tesla Coils

->  BP> I'm interested in building a Tesla coil using a ham
->  BP> transmitter power source (if it's possible).
->
-> Why would you want to do that?

Because it's there! (The Kenwood TS-430S on my desk).  I have an
RF source, I don't have a neon sign xfmr, etc.  For economy, out
of curiosity, etc.
 
 ! Origin: Bashful Pervert BBS  (305) 472-7715  (1:369/120)


  Date: 06-07-94  18:07
  From: James Meyer                                 
    To: Roy J. Tellason                             
  Subj: Tesla Coils

On 06-05-94, ROY J. TELLASON wrote to BOB PATTEN and said:

RJ>  BP> building a Tesla coil using a ham transmitter as the
RJ>  BP> power source (if it's possible).
RJ>
RJ> Why would you want to do that?

        Efficiency, Roy.  That and the fact that it would be much
        easier to only have to wind and tune the high voltage
        secondary.  You don't have to mess around with neon sign
        transformers and spark gaps.

        If Tesla were alive and experimenting today, he wouldn't
        still be using spark gaps to produce his RF to drive his
        coils with.

        Jim
 ! Origin: (Durham, NC) 919-286-4542 (1:3641/224)

  Date: 06-08-94  07:07
  From: Dave Mcknight                           
    To: Richard Quick                                
  Subj: 10KVA Tesla Coil

RQ> Nothing like this ever occured, though many of the effects
RQ> of his oscillators were even stranger. He experimented with
RQ> mechanical, and electromechanical, oscillators in addition 
RQ> to the purely electrical devices such as the Tesla coil.

Although this might be off topic, could you post a brief
explanation of the mechanical and electromechanical oscillators 
Tesla experimented with?  I've read a number of books on his
coils, but this is the first I've heard of this.
 
 ! Origin: (614)861-8377 (1:226/110)


  Date: 06-08-94  01:18
  From: Bob Patten                                 
    To: Richard Quick                              
  Subj: Tesla Coils

-> There are at least two ways that I can think of to run a coil
-> from a driver such as this. But I would not advise doing it.
-> The ham equipment, powerful as it is, is not designed to drive
-> a coil to spark.

-> You would be better (and it would be much safer for the HAM
-> xmittr) to design a tube driven or spark gap excited tank
-> circuit to drive a coil.

The KW amplifier is tube drive, but lowest frequency it works on
is 3.5Mhz.  So what are the two ways that you can think of?  I'm
just trying to collect all the possibilities before I decide how
to go. I may end up shopping for a neon sign xfmr and building
the conventional design...
 
 ! Origin: Bashful Pervert BBS  (305) 472-7715  (1:369/120)


  Date: 06-08-94  20:37
  From: Michael Diresta                               
    To: Richard Quick                                     
  Subj: Tesla Coils

Thanks Richard, That info should keep me busy for some time. I'll
let you know how I make out.  (508) 474-0328 (1:324/114)


  Date: 06-09-94  18:03
  From: Andrew Sempere                            
    To: Richard Quick                             
  Subj: 10KVA Tesla Coil

RQ> "Reduced power" on the Wardenclyff machine would be around
RQ> 250 KVA guesstimate. Note that this is not the Colorado 
RQ> Springs machine which processed around 250 KVA when maXed.
RQ> ... Colorado Springs, insects took flight covered in
RQ> St. Elmo's Fire, horses were pulling electrical arcs (not 
RQ> static electricity) from the ground to their shoes, local
RQ> atmospheric illumination (corona type effects) around the 
RQ> machine, etc..

Really very interesting... I think I might do some research on
Tesla myself, sounds quite fascinating.  Do any of Tesla's 
plants (besides Niagra) still exist?  What about the Wardenclyff 
plant?  -Andrew  - Andover, MA, USA - (508) 474-0328 (1:324/114)


  Date: 06-08-94  03:46
  From: Greg Purvis                                   
    To: Norman Cardillo                             
  Subj: TESLA COIL, But Power & O

 NC> Somebody once said that power should be transmitted with
 NC> Tesla Coils instead of using wires, because those wires 
 NC> running everywhere cause a health problem. 

I read an article in the New Yorker some years back which I tore
out and kept, about some people who were hunting down evidence 
that powerline EMF's were causing their own honorable amount of 
havoc with white cells, fetal gestation, and other problems 
within the systems of people who lived close to HTWires and 
transformers, and so on. I've since seen other references (and I
DON'T have copies, unfortunately) to one or more people mentioned 
in this first article which refutes either the motives of these 
people or the conclusions that they've come to. The New Yorker 
article is several pages each over three issues, so if you are 
interested in reading it, please let me know where I can send
photocopys. I'm afraid it's too much to scan and have our NEC's 
travel along on their dime.
 
I can't and don't dwell on this subject about how the raw bi- 
product(s) of electricity may harm people.  Who can?  Still, 
if within my lifetime and my financial means there is a way to 
identify problems and compensate for those problems, I'd like to 
know of them, and how I may be able to take part in a 'cleaner 
electrical future'.

I need information too, so just leave a note to me if you want
copies of this article and you've got it.  I look forward to more
discussion on this topic.

... Three types of lies: lies, damn lies, and statistics - Mark
     Twain

Pembroke Ont. CAN. 613-735-5170 (1:241/12)


  Date: 06-08-94  19:44
  From: Andrew Sempere                              
    To: Randy Dixon                                
  Subj: Tesla coils

 RD> I knew a Guy whom made one and lit up a guy 2 houses 
 RD> down whom was using his telephone, so please be careful 
 RD> when testing these toys... Randy

Hmmmm... I can think of a few people I'd like to light up :) Just
kidding, thanks for the warning, I'll keep it in mind when it
comes time to flip the switch.. Andrew (508) 474-0328 (1:324/114)


  Date: 06-10-94  20:54
  From: Richard Quick                                 
    To: Dave Mcknight                                
  Subj: 10KVA Tesla Coil

-=> Sez Dave Mcknight to Richard Quick <=-

 DM> Although this might be off topic, could you post a brief
 DM> explanation of the mechanical and electromechanical
 DM> oscillators Tesla experimented with?  I've read a number of
 DM> books on his coils, but this is the first I've heard of
 DM> this.

OK, Real brief...

Tesla invented some very accurate mechanical and electro-
mechanical oscillators. Several of these were patented.

These oscillators were steam or compressed air fired. The
electromechanical oscillators were made to produce a frequency
stable alternating current by mounting a coil around a
mechanically oscillating armature.

Tesla also held patents on high speed, high frequency
alternators. By using the frequency stable output from a steam
fired electromechanical oscillator to excite the field windings
on the high speed alternator, a high power, frequency stable, CW
RF current was produced. This is radio.

Tesla continued to develop the circuit for power and efficiency
and included many variations and modifications in his patent
applications covering all aspects of his grounded tuned circuit
(multiplexing, receiver circuits, power supplies, etc) 1890-1893

The radio circuits are not that obvious until you look at the
steam fired generator sets that were used power them. The RF
alternators were weighing several hundreds of pounds by 1893;
they were steam engine driven (later turbine), ran up to 20,000
RPM, and produced 8 KVA (plus) of RF signal. The field coils on
the high speed alternator could be excited by frequency stable AC
signal from an electromechanical oscillator (these were running
10+ horsepower in 1893) and the steam pressure was closely
regulated. The signal from the antenna was very stable CW.

The high speed alternators were patented under the description
"System for Arc Lighting", and indeed, he did sell a generator
set to the city if New York for powering several blocks of his
arc lamps. Run unregulated, they could be used to make killer
light shows, run with speed regulation they made excellent CW
RF power supplies.

By this time he was also patenting vacuum sealed oil capacitors,
high speed mechanical breaks (sparkgaps), air core (coil)
transformers, to name a few.

The Complete Patents shows the parallel development in these
areas; both the complexity of the circuits, and the power of the
steam driven alternators and electromechanical oscillators. I
should note here that many patents were issued years after they
were submitted (and many years after their invention), and many
many more ideas and techniques went unpatented.

Photos, sketches, and the related patent numbers and dates of
much of this equipment is discussed by Tesla in his depositions
to his attorneys, and these depositions are published as: Nickola
Tesla On His Work With Alternating Currents and Their Application
to Wireless Telegraphy, Telephony, and Transmission of Power.

Note this work was all done after he patented a motor based on a
rotating magnetic field (AC induction motor) and other key
elements of our "modern" power grid, and that this was before his
high powered resonator work at Colorado Springs and Wardenclyff.


  Date: 06-10-94  22:43
  From: Richard Quick                           
    To: Andrew Sempere                          
  Subj: 10KVA Tesla Coil

 AS> Do any of Tesla's plants (besides Niagra) still exist?  What
 AS> about the Wardenclyff plant?  -Andrew

Not to my knowledge, all the later stuff... gone. Wardenclyff was
broken into by vandals who smashed Tesla's lifetime accumulation
of tubes, xfmrs, radios, robot projects, etc.. The thieves stole
for scrap what they could not smash; all the boiler brass, copper
motor/generator windings, etc.. were stripped. Witnesses stated
that after one particularly bad week of vandalism all the windows
had been smashed, office furnature lay broken outside in the
rain, and pages of Tesla's hand written notes were blowing in the
wind. At this point Tesla was close to destitute and could not
afford a caretaker at the uncompleted plant.


  Date: 06-10-94  22:25
  From: Richard Quick                      
    To: Bob Patten                           
  Subj: Tesla Coils

 -> There are at least two ways that I can think of to run a coil
 -> from a driver such as this. But I would not advise doing it.
 -> The ham equipment, powerful as it is, is not designed to
 -> drive a coil to spark.

 BP> The KW amplifier is tube drive, but lowest frequency it
 BP> works on is 3.5Mhz.

Tube coils work best around 450 kHz or less. Your output will be
more corona than lightning at 3.5 mHz; excellent for lighting up
vacuum tubes and what not, but not a good sparker.

 BP> So what are the two ways that you can think of? I'm just
 BP> trying to collect all the possibilities before I decide how
 BP> to go.  I may end up shopping for a neon sign xfmr and
 BP> building the conventional design...

The first way is to wind ~3.5 mHz coil, then carefully match the
frequency output of the transmitter to the frequency of the coil,
(they must be within a few kHz). When both xmitr and coil are at
the same frequency, the output of the xmitr may be run directly
into the coil base wire. This is a base fed secondary coil driven
by an RF current. Problems include impedance matching, and
frequency drift.

The second way is to inductively couple a coil set. A primary
coil is made up of 5-8 turns of heavy conductor. One end of the
primary coil is grounded with the xmitr housing, the other end is
fed the xmitr output. The 3.5 mHz coil is set inside (or placed
in close proximity to) the heavy primary coil, and the base wire
of the secondary is grounded as well. The coil will be excited by
induction from the energized primary. Problems include low
efficiency (due to low coupling coefficients, and low peak
powers), and difficulties in frequency matching the two circuits.

Depending on the nature of the experiments to be performed, each
method has it's advantages and disadvantages. You would probably
end up switching back and forth between these two.

The driver (radio transmitter in this instance) will not give any
real goose to a Tesla coil (which is simply a 1/4 wave
resonator). In practice tube coilers tend to operate at much
lower frequencies with a Class C type amplifier, where additional
power tubes may be ganged up for more KVA. But all of these CW
(Continuous Wave) circuits are peak power limited: In other words
your peak coil discharges are not much greater than the rms
ratings of your power tube(s).

When you go to spark gap excited tank circuits you lose most of
your CW (unless your are a real spark gap engineer) but your peak
powers climb through the proverbial roof. Even a cheapy, home
built in three hours, salt water capacitor will give you a much
greater peak power than your 3 KVA xmitr run flat out. A cheapy
salt water cap is much less expensive to replace or simply scrap
than a quality power tube(s).

If you are really serious about tube coils, use the proper
frequency range class C amplifier circuit.

VACUUM TUBE INDUSTRIES, INC., 506 North Warren Ave., P.O. Box
2009, Brocton, Massachusetts, 02405-2009,  specializes in 450
kHz power tubes for use in commercial RF induction heaters. They
carry a full line of filament xfrmrs and HV plate xfmrs, cooling
jackets, power controllers etc.. These are the ideal type tubes
for Tesla Coils that are driven by Class C amplifiers.


  Date: 06-10-94  23:21
  From: Richard Quick                           
    To: Randy Dixon                             
  Subj: Tesla coils

 -=> Sez Randy Dixon <=-

 RD> I knew a Guy whom made one and lit up a guy 2 houses
 RD> down whom was using his telephone, so please be careful
 RD> when testing these toys... Randy

The biggest thing missed for safe coil operation is a heavy,
dedicated, RF ground that is completely electrically isolated
from all other ground points. If you have a ground loop problem
(Tesla Coil), and your ground is the same as Ma Bell is using,
then you can expect some complaints/problems.

Tesla coil experiments require that the system ground have
enormous surface area in contact with moist earth. All ground
connections must be short, direct, and traversed with large
surface area conductors such as strap, heavy coax shield, copper
pipe, aluminum strips etc..

Don't ground to the water pipe! Don't ground your coil to your
breaker box! Avoid: telephone, cable TV, antenna or power utility
grounds, and gas pipes. Don't ground to conductors that stick up
in the air: gutters, downspouts, fences, etc..

Do sink pipes and rods into the ground. Bury wire screen mats.
Throw aluminum flashing into a water filled ditch, well, stream,
pond, or lake. Connect iron or galvinized sewer pipe and
culverts. Grounds should be kept wet. All connections should be
short with lots of surface area. I like a bunch of 8' copper
pipes driven into small depressions around a back yard: soldered
connections, 1/2" ground strap, central connection made no more
than 20 feet from the base of the coil. Another favorite: buried
hydraulic car lift lacking a direct metal connection to the
compressor.


  Date: 06-08-94  07:07
  From: Dave Mcknight                          
    To: Richard Quick                           
  Subj: 10KVA Tesla Coil

 RQ> Nothing like this ever occured, though many of the effects
 RQ> of his oscillators were even stranger. He experimented with
 RQ> mechanical, and electromechanical, oscillators in addition   
 RQ> to the purely electrical devices such as the Tesla coil.

Although this might be off topic, could you post a brief
explanation of the mechanical and electromechanical oscillators
Tesla experimented with?  I've read a number of books on his
coils, but this is the first I've heard of this.
OH (614)861-8377 (1:226/110)


  Date: 06-10-94  20:54
  From: Richard Quick                            
    To: Dave Mcknight                            
  Subj: 10KVA Tesla Coil

 -=> Sez Dave Mcknight to Richard Quick <=-

 DM> Although this might be off topic, could you post a brief
 DM> explanation of the mechanical and electromechanical
 DM> oscillators Tesla experimented with?  I've read a number of
 DM> books on his coils, but this is the first I've heard of
 DM> this.

OK, Real brief...

Tesla invented some very accurate mechanical and electro-
mechanical oscillators. Several of these were patented.

These oscillators were steam or compressed air fired. The
electromechanical oscillators were made to produce a frequency
stable alternating current by mounting a coil around a
mechanically oscillating armature.

Tesla also held patents on high speed, high frequency
alternators. By using the frequency stable output from a steam
fired electromechanical oscillator to excite the field windings
on the high speed alternator, a high power, frequency stable, CW
RF current was produced. This is radio.

Tesla continued to develop the circuit for power and efficiency
and included many variations and modifications in his patent
applications covering all aspects of his grounded tuned circuit
(multiplexing, receiver circuits, power supplies, etc) 1890-1893

The radio circuits are not that obvious until you look at the
steam fired generator sets that were used power them. The RF
alternators were weighing several hundreds of pounds by 1893;
they were steam engine driven (later turbine), ran up to 20,000
RPM, and produced 8 KVA (plus) of RF signal. The field coils on
the high speed alternator could be excited by frequency stable AC
signal from an electromechanical oscillator (these were running
10+ horsepower in 1893) and the steam pressure was closely
regulated. The signal from the antenna was very stable CW.

The high speed alternators were patented under the description
"System for Arc Lighting", and indeed, he did sell a generator
set to the city if New York for powering several blocks of his
arc lamps. Run unregulated, they could be used to make killer
light shows, run with speed regulation they made excellent CW
RF power supplies.

By this time he was also patenting vacuum sealed oil capacitors,
high speed mechanical breaks (sparkgaps), air core (coil)
transformers, to name a few.

The Complete Patents shows the parallel development in these
areas; both the complexity of the circuits, and the power of the
steam driven alternators and electromechanical oscillators. I
should note here that many patents were issued years after they
were submitted (and many years after their invention), and many
many more ideas and techniques went unpatented.

Photos, sketches, and the related patent numbers and dates of
much of this equipment is discussed by Tesla in his depositions
to his attorneys, and these depositions are published as: Nickola
Tesla On His Work With Alternating Currents and Their Application
to Wireless Telegraphy, Telephony, and Transmission of Power.

Note this work was all done after he patented a motor based on a
rotating magnetic field (AC induction motor) and other key
elements of our "modern" power grid, and that this was before his
high powered resonator work at Colorado Springs and Wardenclyff.


  Date: 06-10-94  22:43
  From: Richard Quick                           
    To: Andrew Sempere                           
  Subj: 10KVA Tesla Coil

 AS> Do any of Tesla's plants (besides Niagra) still exist?  What
 AS> about the Wardenclyff plant?  -Andrew

Not to my knowledge, all the later stuff... gone. Wardenclyff was
broken into by vandals who smashed Tesla's lifetime accumulation
of tubes, xfmrs, radios, robot projects, etc.. The thieves stole
for scrap what they could not smash; all the boiler brass, copper
motor/generator windings, etc.. were stripped. Witnesses stated
that after one particularly bad week of vandalism all the windows
had been smashed, office furnature lay broken outside in the
rain, and pages of Tesla's hand written notes were blowing in the
wind. At this point Tesla was close to destitute and could not
afford a caretaker at the uncompleted plant.


  Date: 06-08-94  19:00
  From: Don Kimberlin                        
    To: Terry Smith                             
  Subj: Tesla Coils

TS>You could quite easily turn a Tesla coil into a transmitter,
TS>generating sign types not approved for HAM use, at strengths
TS>well above Part 15 limits.  Below 9 kHz such limits would not
TS>apply.

TS>Other than by only operating it well inside the boundaries of
TS>a BIG piece of private property, I wonder what kind of induced
TS>and radiated signal strenght are produced by large Tesla
TS>coils.  I'd guess that what sounds like a 50 KVA unit
TS>discussed here probably substantially exceeds Part 15
TS>unintentional radiator emmissions limits.

TS>If Richard, or the others playing with toys, notice...  Over
TS>what range of frequencies are you guys producing emmissions,
TS>and at what kind of field/distance?  I'd imagine some coils
TS>produce an unstable (in terms of frequency) output over a 10
TS>or 100 to 1 range, while others may be stable within 5% or
TS>less.  Is this a reasonable presumption?

TS>Have any of these coils been monitored with field strength
TS>meters, or spectrum analyzers with calibrated antenna sets?

...I hate to raise that ominous spectre, but I've heard a couple
of non-tech blurbs over the past year or so about such matters.
One was a chap somewhere around San Francisco who got hold of an
old Federal enclosed arc generator (Federal made U.S. versions of
the Danish Poulsen arc, the largest of which was a megawatt,
placed in the WWI US Navy sparker at Bordeaux, France as a
back-up in case the Germans cut the transatlantic telegraph
cables to the U.S.), and another story - might have been the same
person - purchased the RCA Marconi-made 300 kW sparkers from
Bolinas, CA (just north of SFO) for junk prices.  Seems the
government people got right on his case, cited "safety reasons"
more than RFI.  Seems like that stuff generates spurs clear up
beyond daylight, at least so the government was supposed to be
claiming...not a nice thought, if one has the Feds on their
tail...kind of like a "forbidden fruit" of electronics, mayhaps?
 Concord,N.C. (704)792-9241  (1:379/37)


  Date: 06-11-94  00:14
  From: Terry Smith                         
    To: Richard Quick                       
  Subj: 10KVA Tesla Coil

 RQ> The tower of the Wardenclyffe commercial plant built in 1901
 RQ> was 167 feet tall (air terminal) on a stone and concrete

 RQ> "Reduced power" on the Wardenclyff machine would be around
 RQ> 250 KVA guesstimate. Note that this is not the Colorado      
 RQ> Springs

Trying to do some projections, was this system designed to
operate at around 15-20 megavolts, with around 15-40 mA current
being sustained?  

Is your 10 KVA coil discussed here operated around 2 MV, 5 mA ?

That "little one" almost sounds safe to play with!  <g>

Terry

ps:  On thinking about FCC considerations, it's pretty likely
that these Tesla coils are highly in violation of today's rules
and regs.  Even some of the little units used in labs to ignite
gas mixes probably exceed Part 15 limits.  

What are the frequency extremes you've used for various coils?

Do you think a Tesla coil could be built in such a manner as to
confine primary emmissions to 6.78 MHz +/-15 KHz?  This is the
lowest frequency of the ISM band (FCC Part 18), in which power
and signal emmissions in band are unlimited.  The 2nd and 4th
harmonics of 6.78 MHz are also ISM, and therefore unrestricted. 
Out of band signals would have to be less than 10 uV/m at 1600 M
to be legal on such frequencies, or if operated outside ISM bands
at substantially over 500 watts.  

I suspect this means that to be legal, any large Tesla coils
would have to be built outside the US.  I presume you are
operating well below the lowest ISM frequency and emit signals
that would create more than a barely audible crackle on a radio
with an AM detector 100 feet away?  (The latter being a rough
translation of 10 uV/m @ 1600 M to .5 mV/m @ 100')
 ! Origin: Charges filed under Ohms Law!  (203)732-0575 BBS
(1:141/1275)

  Date: 06-12-94  14:59
  From: Andrew Sempere                             
    To: Bob Patten                                
  Subj: Tesla Coil

Thanks for the tesla coil plans! I got them on Wednesday (Sorry
about the extra stamp)  Thanks also for the section on Kirlian
photography, I'll let you know how it all turns out... -Andrew 
 Andover, MA, USA - (508) 474-0328 (1:324/114)


  Date: 06-12-94  08:28
  From: Richard Quick                           
    To: Don Kimberlin                            
  Subj: Tesla Coils

 DK> ...I hate to raise that ominous spectre...

 DK> old Federal enclosed arc generator (Federal made U.S.        
 DK> versions of the Danish Poulsen arc, the largest of which was 
 DK> a megawatt,

and

 DK> person - purchased the RCA Marconi-made 300 kW sparkers from
 DK> Bolinas, CA (just north of SFO) for junk prices.  Seems the
 DK> government people got right on his case, cited "safety       
 DK> reasons"

But it must also be understood that both the HF generator and the
Marconi coil were designed specificlly to transmit RF. These
designs aimed for power, (at the time thought essential for long
distance xmission), and not so much for a stable frequency.

I have photocopies of pictures taken of the Marconi coils. No way
could a clean signal be produced by this work. And there IS the
"safety problem"; the spark gaps, boilers, generator sets, etc.,
should be considered hazardous. I know that in Illinois where
they have steam tractor meets, all steam boilers must be
inspected and licensed by the state.


  Date: 06-13-94  22:29
  From: Richard Quick                             
    To: Terry Smith                               
  Subj: 10KVA Tesla Coil

 RQ> "Reduced power" on the Wardenclyff machine would be around
 RQ> 250 KVA guesstimate.

 TS> Trying to do some projections, was this system designed to
 TS> operate at around 15-20 megavolts, with around 15-40 mA
 TS> current being sustained?

Boy are you ever in the stone age on this subject. 15 - 40 mA????

Tesla's peak power ran over a gigawatt. (work it backwards...)

 TS> Is your 10 KVA coil discussed here operated around 2 MV, 5
 TS> mA ?

My 10" coil has a peak power of over 2 megawatts.

 TS> That "little one" almost sounds safe to play with!  <g>

yea right..., and you are almost an order of magnitude out of the
ballpark with your deductions. You clearly show that you have not
even looked up or attempted to understand a simple spark excited
tank circuit. Much less a resonate transformer. Now you proceed
to go off about the legal ramifications of a circuit you do not
understand.

 TS> ps:  On thinking about FCC considerations,
 TS> it's pretty likely that these Tesla coils are highly in
 TS> violation of today's rules and regs.

It's even more likely you don't have a clue...

 TS> Even some of the little units used in labs to ignite gas
 TS> mixes probably exceed Part 15 limits.

Are you paid to do this with your time or do you volunteer? Do
you have a job?

 TS> What are the frequency extremes you've used for various
 TS> coils?

I would have to open up my lab journal, but I can tell you what
FIDO extremes I have seen.

 TS> Do you think a Tesla coil could be built in such a manner as
 TS> to confine primary emmissions to 6.78 MHz +/-15 KHz?

Sure, why don't you spend a minute and sketch a circuit diagram
and design a resonator for this.

 TS> This is the lowest frequency of the ISM band (FCC Part 18),
 TS> in which power and signal emmissions in band are unlimited.
 TS> The 2nd and 4th harmonics of 6.78 MHz are also ISM, and
 TS> therefore unrestricted.

Humm, I know you are unrestricted. Frequency Extremes...

 TS> Out of band signals would have to be less than 10 uV/m at
 TS> 1600 M to be legal on such frequencies, or if operated
 TS> outside ISM bands at substantially over 500 watts.

Oh, yes I am sure this applies....

 TS> I suspect this means that to be legal, any large Tesla coils
 TS> would have to be built outside the US.

Boy you suspect me too... even after I posted my name and address
to the whole world....

 TS> I presume you are operating well below the lowest ISM
 TS> frequency and emit signals that would create more
 TS> than a barely audible crackle on a radio with an AM detector
 TS> 100 feet away?  (The latter being a rough translation of 10
 TS> uV/m @ 1600 M to .5> mV/m @ 100')

From the very beginning of your post to me you have been very
much incorrect in your projections, assumptions, and suspicions.
You would waste a lot of my valuable time defending a legal,
educational, and entertaining field of discussion and experi-
mentaion. Properly built and operated, Tesla coils are not the
nightmare interference you are.

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


  Date: 06-13-94  23:07
  From: Richard Quick                               
    To: Terry Smith                               
  Subj: 10KVA Tesla Coil

 TS> ps:  On thinking about FCC considerations, it's pretty
 TS> likely that these Tesla coils are highly in violation of
 TS> today's rules and regs.

 TS>  ! Origin: Charges filed under Ohms Law!  (203)732-0575 BBS

ps: You are twice now accusing me of being in "violation" of
something you appear to know nothing (Tesla Coils) about???
My neighbors nextdoor don't have problem, why do you???
If it means anything to you, this work has been going on since
Faraday first discharged a capacitor.

Now Terry, you and I have discussed capacitors for these
projects, and I can honestly say I appreciated your input,
but for some reason you act now like you fell out a tree.

Or, could that have been another Terry Smith? I seem to recall a
lot of Terry Smith's out here getting their messages crossed
up... Showing up in their personal mailboxes etc.. I don't know.
I have been on a year and have never had a problem with Terry
Smith before, seemed like a resonable guy, offered up a couple of
prospective capacitor types for Tesla projects.

Well regardless: practical circuit assistance, capacitor (or
coil) designs, or construction plans, spark gap ideas, grounding
techniques, references, etc. are always welcome and appreciated.

                                    Thank You

  Date: 06-13-94  08:29
  From: Tom Moeller                            
    To: Bob Patten                              
  Subj: Tesla Coils

Bob Patten wrote in a message to Terry Smith:

->  BP> I'm interested in building a Tesla coil using a ham
->  BP> transmitter power source (if it's possible).  

 BP> Well, in my case, I could always key it and make some CW
 BP> QSO's whilst demonstrating the effects of the Tesla coil.  I
 BP> imagine it would radiate a clean CW signal...

Yeah, on visual as well as RF! |-} and no messy lamp filaments to
burn out either.

    Tom 

  Date: 06-14-94  08:22
  From: Bob Patten                                
    To: Richard Quick                             
  Subj: Tesla Coils

-> If you are really serious about tube coils, use the proper
-> frequency range class C amplifier circuit.

-> VACUUM TUBE INDUSTRIES, INC., 506 North Warren Ave., P.O. Box
-> 2009, Brocton, Massachusetts, 02405-2009,  specializes in 450
-> kHz power tubes for use in commercial RF induction heaters.
-> They carry a full line of filament xfrmrs and HV plate xfmrs,
-> cooling jackets, power controllers etc.. These are the ideal -
> type tubes for Tesla Coils that are driven by Class C 
-> amplifiers.

Thanks for all the info Richard.  I did a hard copy of the full
message and will study it for ideas.  I also requested info on
publications about tube coils from the Tesla Society in Colorado
Springs that I read about in someone else's message here...
 ! Origin: Bashful Pervert BBS  (305) 472-7715 (1:369/120)


  Date: 06-15-94  02:16
  From: Bob Patten                               
    To: Tom Moeller                              
  Subj: Tesla Coils

BP> I'm interested in building a Tesla coil using a ham transmitt
BP> power source (if it's possible).

BP> Well, in my case, I could always key it and make some CW
BP> QSO's whilst demonstrating the effects of the Tesla coil. 
BP> I imagine it would radiate a clean CW signal...

-> Yeah, on visual as well as RF! |-} and no messy lamp filaments
-> to burn out either.

What gave me the idea was the memory of running a KW to a short
top loaded vertical on 3.5Mhz.  On a humid night, it would shoot
out a horiz spark about a foot long...
  (305) 472-7715  28800 V.32bis (1:369/120)


  Date: 06-16-94  00:10
  From: Andrew Sempere                        
    To: Richard Quick                            
  Subj: 10KVA Tesla Coil

 RQ> broken into by vandals who smashed Tesla's lifetime
 RQ> accumulation of tubes, xfmrs, radios, robot projects, etc..  
 RQ> The thieves stole for scrap what they could not smash; all   
 RQ> the boiler brass, copper motor/generator windings, etc..     
 RQ> were stripped. Witnesses stated that after one particularly  
 RQ> bad week of vandalism all the windows had been smashed,      
 RQ> office furnature lay broken outside in the rain, and pages   
 RQ> of Tesla's hand written notes were blowing in the wind. At   
 RQ> this point Tesla was close to destitute and could not
 RQ> afford a caretaker at the uncompleted plant.

That sucks! What a waste...   When did Tesla die?  
 Andover, MA, USA - (508) 474-0328 (1:324/114)


  Date: 06-15-94  17:39
  From: Jamar Neal                               
    To: Richard Quick                             
  Subj: Tesla

Were did Tesla fit into the battle for the electricity market
between Edison and Westinghouse?  This was about the right time
period right?  Jamar 314-339-0248 (1:287/516)


  Date: 06-14-94  22:39
  From: Don Kimberlin                         
    To: Richard Quick                           
  Subj: Tesla Coils

RQ> DK> ...I hate to raise that ominous spectre...

RQ> DK> old Federal enclosed arc generator (Federal made U.S.
RQ> DK> versions of the Danish Poulsen arc, the largest of which
RQ> DK> was a megawatt,

RQ>and

RQ> DK> person - purchased the RCA Marconi-made 300 kW sparkers
RQ> DK> from Bolinas, CA (just north of SFO) for junk prices. 
RQ> DK> Seems the government people got right on his case, cited
RQ> DK> "safety reasons"

RQ>But it must also be understood that both the HF generator and
RQ>the Marconi coil were designed specificlly to transmit RF. 
RQ> These designs aimed for power, (at the time thought essential
RQ>for long distance xmission), and not so much for a stable
RQ>frequency.

RQ>I have photocopies of pictures taken of the Marconi coils. No
RQ>way could a clean signal be produced by this work. And there
RQ>IS the "safety problem"; the spark gaps, boilers, generator
RQ>sets, etc., should be considered hazardous. I know that in
RQ>Illinois where they have steam tractor meets, all steam
RQ>boilers must be inspected and licensed by the state.

...all the more important then, in the case of those who would
build Tesla coils today, that they understand how to make really
high-efficiency ones, then, eh?    I know an awful lot of the
Pop-Tronics "projects" of the old magazines resulted in awfully
sloppy things that thrilled people with six inches or a foot of
discharge, which worked out to a horrible inefficiency for the
input they were running....
 Concord,N.C. (704)792-9241  (1:379/37)


  Date: 06-16-94  23:36
  From: Sjoerd Schaafsma                         
    To: Richard Quick                            
  Subj: Re: Tesla Coils, Video

Howdy Richard:

 RQ> If you have any problems, questions, comments, corrections,
 RQ> etc., please post me. Since your tape was sent out of the
 RQ> country I would appreciate it if you would let me know when
 RQ> it arrives.

Thanks a bunch Richard, I'll let you know as soon as it arrives.  
I hope the MO I sent was enough to cover your postage, I have
little idea what it is, but it usually is less than the
comparable service in Canada.   I'm looking forward to seeing the
sparks fly! ... Sjoerd Schaafsma - An occasional 8 bit holdout
  [403]327-9731 Lethbridge,AB (1:358/17)

  Date: 6-16-94  20:45
  From: Richard Quick                   
    To: Bob Patten                       
  Subj: Tesla Coils

 -> If you are really serious about tube coils, use the proper
 -> frequency range class C amplifier circuit. RQ

 BP> Thanks for all the info Richard. I did a hard copy of the
 BP> full message and will study it for ideas.

Your very welcome. I hope I was of some help.

 BP> I also requested info on publications about tube coils from
 BP> the Tesla Society in Colorado Springs that I read about in
 BP> someone else's message here...

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.
............................................................
> Retrieved from archives.

>  Date: 06-15-94  02:16
>  From: Bob Patten
>    To: Tom Moeller
>  Subj: Tesla Coils

BP>What gave me the idea was the memory of running a KW to a
BP>short top loaded vertical on 3.5Mhz.  On a humid night, it
BP> would shoot out a horiz spark about a foot long...
.............................................................

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.

A Tesla coil normally operates at a lower frequency to transform
high power. Larger capacitors increase power, but reduce the tank
circuit frequency. To compensate for the reduced frequency in the
oscillator (Tesla Tank) circuit; the resonator (Tesla Coil)
frequency must also be reduced. This maintains a match or "tune".

The most common practice used in maintaining the tune of the 1/4
wave (voltage producing) resonator (coil) is to increase the
conductor length, and/or, top load the coil with some type
capacitive discharger. In tube (CW) coils; larger dischargers
(conductive spheres, toroids, etc.) are not satisfactory sparkers
unless some pointed surface is provided for breakout. Adding wire
length to the resonator for frequency reduction seems to work
best for tube type or CW coils. But then a problem arises...

The impedance increases rapidly with the use of longer cond-
uctors. To get around this, larger, lower resistance conductors
must be wound on fatter coil forms. This goes a long way towards
maintaining the efficiency or "Q" of the Tesla Coil, or properly
the " 1/4 slow-wave helical resonator".

By the way, using tube amplifier circuits it is possible to drive
higher frequency resonators with good power. The resonator
geometries at these higher frequencies must change to reach
higher Qs. As the coil's efficiency drops way off as frequency
goes up. A good example of a resonate structure at higher
frequency is the typical tube driven cavity resonator kitchen
utensil, the microwave oven. Some examples of resonate structures
include: the tube driven Sloan X-Ray machine (1935, coaxial
helical resonator), the pure RF cavity resonator Hanson
documented 1938, and the Phermex 50 mHz cavity accelerator. In
addition there have been several Russian attempts at RF cavity
resonate fusion machines. Tesla determined that the earth is an
electrically resonate structure (cavity) in what is now know as
the Shumann Cavity.

This was all started with Tesla's resonate coils.


  Date: 06-17-94  20:26
  From: Richard Quick                           
    To: Andrew Sempere                          
  Subj: 10KVA Tesla Coil

 AS> When did Tesla die?

10:30 P.M on January 7,1943 in his New York hotel room.


  Date: 06-17-94  18:01
  From: Richard Quick                               
    To: Jamar Neal                                  
  Subj: Tesla

 -=> Sez Jamar Neal to Richard Quick <=-

 JN> Were did Tesla fit into the battle for the electricity
 JN> market between Edison and Westinghouse?  This was about the
 JN> right time period right?

Edison had already established a lab here in the US before Tesla
arrived in New York from Europe. Edison was proposing that DC
power be used for residential lighting and industry. Tesla worked
for some months in Edison's lab, and a definite difference of
opinion developed. Tesla left disgusted.

Tesla realized that DC was essential in certain industrial
applications, such as producing aluminum; but for most other
purposes, alternating currents (AC) worked as well as DC, and
frequently AC worked much better. Tesla held patents for motors
and alternators based on his system of AC power production, step
up transformation, transmission, step down transformation, and
utilization. His motor operated without carbon brushes, running
instead on his patented rotating magnetic field. It always turned
the same direction regardless of which way the plug was wired.

Edison's system of DC power production and transmission was very
inefficient. The amount of copper involved was amazing. Two
blocks from a dynamo station the DC voltage was very high, but 10
blocks away people complained about dim lights and fires from
overheated conductors. Lighting New York City was going to
require at least 5 DC steam powerplants in the center of the
city, one in each major section. The coal pollution was already
dense, and steam boiler explosions were becoming both worse and
more frequent as more and larger boilers were operated at higher
pressure. Tesla offered a way to produce electricity at a remote
site and then conduct the power to the population centers.

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.


  Date: 06-17-94  20:17
  From: Richard Quick                                
    To: Don Kimberlin                               
  Subj: Tesla Coils

 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....

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

A heavy, dedicated, RF ground is a must for any serious coiling.
Experiments should then seek to convert every possible watt into
spark, where the energy is consumed as heat, light, sound, etc..
The coil base wire is the source of most of the spurious signal.
The output here is a low voltage RF current at quite a few rms
amps. The signal seems to conduct better than it radiates, so
just make sure your ground path is equipped for it.

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


  Date: 06-17-94  03:05
  From: Terry Smith                         
    To: Richard Quick                          
  Subj: 10KVA Tesla Coil

 TS> ps:  On thinking about FCC considerations, it's pretty
 TS> likely that these Tesla coils are highly in violation of
 TS> today's rules and regs.

 RQ> ps: You are twice now accusing me of being in "violation" of
 RQ> something you appear to know nothing (Tesla Coils) about???
 RQ> My neighbors nextdoor don't have problem, why do you???

I haven't accused you of anything, but I have asked a few
questions I strongly suspect, after considering some FCC
implications, cannot be answered by anyone in the US in a way
which makes most Tesla projects possible under current
regulations.  June on this year is the month when many engineers
responsible for AM transmitters have to prove that spurious
emmissions are in the microvolt range leaving their transmitter
sites.  In a sense that's another PITA nuisance I've had to spend
hours handling, but it's one that anyone qualified to handle
can understand as contributing to a worthwhile result.  With
current communications policy, lightning would probably be
illegal if men controlled it.  Those RF resources we do control
are ever more tightly regulated, as spectrum is utilized by more
tightly packed users having to share.  The responsible ones among
us try to do so without causing avoidable interference to others. 

I join many others here in expressing a curious interest in Tesla
devices and technology.  The more they're discussed, the more I
suspect Don Kimberlin's comments about their becoming a legal
"forbidden fruit" in the US are on target.  

 RQ> If it means anything to you, this work has been going on
 RQ> since Faraday first discharged a capacitor.

I take a Libertarian view of proper and legal US government
function in general.  In communications, there are cases where
the FCC promotes political agenda issues due to improper
politicking from the Hill.  In general, I see the FCC as an
agency which mostly functions to make communications needed for
interstate commerce function.  As such, I expect serious
electronics operators to learn and follow pertinent regulations. 
Anyone pursuing projects involving megawatts and megavolts over a
period of years certainly falls within that scope, IMHO.  

 RQ> Well regardless: practical circuit assistance, capacitor (or
 RQ> coil) designs, or construction plans, spark gap ideas,
 RQ> grounding techniques, references, etc. are always welcome    
 RQ> and appreciated.

Regardless of legal implications, you've obviously developed a
wealth of interesting knowledge, and some practical experience
that's nearly impossible to refine based exclusively on theory. 
I've seen old spark gap transmitters in museums, originally
operated at much lower powers than large Tesla coils.  They
don't get operated even for demos, as they can't operate legally
under today's R&R.  I personally am interested in seeing the
Tesla threads continue, but is the answer to the "unintentional
radiation" question that it's impossible to operate a large Tesla
coil legally in the US, unless you do so on thousands of acres of
private property?  If so, and folks without huge buffer zones are
making working units and discussing them here, this may be a more
blatant "illegal use of FidoNet" than the kids holding criminal
discussions of CB linears.  Perhaps it's time to consult the echo
moderator for an opinion on how he'd suggest this thread
continue.  Please dump the personal attacks.  

Back to the technology, do you know enough about the time/
frequency/power/conducted-induced-radiated signal relationships
to answer the questions previously on the table, or to compare
them for various coil designs, with and without the third tuning
coil?  Obviously it's a time/energy relationship which allows
describing a single coil as 10 KVA, and also as 2 megawatts peak
output.  Since ionizing voltages are fairly standard calcu-
lations, assuming predictable humidity, airborn dirt, and
temperature conditions, I'd guess the previous voltage guesses
may be close, but the peak currents exceed steady state averages
by the inverse of the duty cycle, which the 2 MW figure for 10
KVA implies averages 0.5%.  That still doesn't say much
about how much variation is normal from a mathematical average. 
Would that be a range of perhaps 1 to 30 amps, or is there any
practical means of estimating within any test setup you or Tesla
have tried?  

As to the 6.78 MHz or other ISM frequencies, I strongly suspect
that imitation lightning is inherently too wideband to possibly
be confined to such allocated legal spectrum.  Perhaps your
research would confirm this? Spectrum over 3,000 GHz is also
pretty much open, and available for crazy experiments by anyone
getting a suitable HAM license.  Obviously that's the "leftovers"
from other users.  In case you're wondering, I raised these ideas
in consideration that sometimes there are legal options possible
to shift the mode of old ideas and continue to pursue them.  The
fact that spark gap transmitters sit disconnected in museums
illustrates the other possibility.  

Quite frankly, I'm amazed that megawatt surges haven't caused
neighbors problems.  You wouldn't believe how much of a nuisance
much lower blanketting power levels can be, when one person
installs some crap quality electronics, which passively transmit
an interfering signal to neighbors. I've seen the AM and FM
broadcast sides of that, and the HAMs see enough of it at even
lower powers that the ARRL recently published several new guides
of research results and suggested patches for assorted problems. 
If you ever get the chance to measure induced fields, which fall
at an inverse cube rate, and radiated fields, which follow an
inverse square law, that would be an interesting adjunct to the
"raw power" research that's been described here.  

No harm meant, but please consider that there may be other
serious aspects to this mix of research and high energy play...
Charges filed under Ohms Law!  (203)732-0575 BBS (1:141/1275)


  Date: 06-19-94  22:18
  From: Richard Quick                             
    To: Terry Smith                               
  Subj: 10KVA Tesla Coil

 -=> Sez Terry Smith to Richard Quick <=-

 TS> ps:  On thinking about FCC considerations, it's pretty
 TS> likely that these Tesla coils are highly in violation of
 TS> today's rules and regs.

 RQ> ps: You are twice now accusing me of being in "violation" of
 RQ> something you appear to know nothing (Tesla Coils) about???
 RQ> My neighbors nextdoor don't have problem, why do you???

 TS> I haven't accused you of anything, but I have asked a few
 TS> questions I strongly suspect, after considering some FCC
                          ^^^^^^^
 TS> implications, cannot be answered by anyone in the US in a
 TS> way which makes most Tesla projects possible under current
 TS> regulations.

You are quite wrong in your suspicions.

 TS> The responsible ones among us try to do so without causing
 TS> avoidable interference to others.

I completely agree, which is why I keep wondering why you keep
posting me about this.

 TS> I join many others here in expressing a curious interest in
 TS> Tesla devices and technology.  The more they're discussed,
 TS> the more I suspect Don Kimberlin's comments about their
                ^^^^^^^
 TS> becoming a legal "forbidden fruit" in the US are on target.
                ^^^^^  ^^^^^^^^^ ^^^^^
You are talking of course about Tesla devices and technology like
the 60 cycle power grid, the AC induction motor, the flyback
transformer, the car distributor and the radio! These are all
Tesla patented domain. You would declare them suspect in their
legality and send us out to buy horses.

What else are you suspicious of?

 TS> Regardless of legal implications, you've obviously developed
                   ^^^^^ ^^^^^^^^^^^^
 TS> a wealth of interesting knowledge, and some practical
 TS> experience that's nearly impossible to refine based
 TS> exclusively on theory.

If you mean to say that I know what I am talking about, yes I do,
and thank you for the complement. I get my hands dirty.

 TS> I've seen old spark gap transmitters in museums, originally
 TS> operated at much lower powers than large Tesla coils. They
 TS> don't get operated even for demos, as they can't operate
 TS> legally under today's R&R.
     ^^^^^^^
But you are again comparing transmitters and coils in the same
sentence. On a transmitter you hang the proper antenna and you
design the system to radiate a signal. On a coil you want to
produce a spark. Two entirely different ideas, two entirely
different designs; separate them in your mind.

 TS> With current communications policy, lightning would probably
 TS> be illegal if men controlled it.

I am afraid you will have to E-Mail God on that one Terry. The
FCC and the echo Moderator can't help you restrict an act of God.

> This mish-mash continued in the next post


  Date: 06-19-94  22:26
  From: Richard Quick                             
    To: Terry Smith                               
  Subj: 10KVA Tesla Coil

> Continued from Previous Post

 TS> I personally am interested in seeing the Tesla threads
 TS> continue, but is the answer to the "unintentional radiation"
 TS> question that it's impossible to operate a large Tesla coil
 TS> legally in the US, unless you do so on thousands of
     ^^^^^^^
 TS> acres of private property?

If you are such an expert on this subject, then why did you not
simply state that the correct proceedure is to run radiating
equipment in a properly shielded enviroment and let it go at
that. A room shielded with hardware cloth and properly grounded
seems much more reasonable (and works to the tune of 100%
perfectly legal, even for transmitting type circuits) than your
insinuation that I need to control thousands of acres of private
property. You need to be: realistic, progressive, comprehensive,
and intellegent; I am sorry if I just don't see that from you at
this time.

 TS> ... this may be a more blatant "illegal use of FidoNet" than
                                     ^^^^^^^
 TS> the kids holding criminal discussions of CB linears.
 TS> Perhaps it's time to consult the echo moderator for an
 TS> opinion on how he'd suggest this thread continue.
 TS> Please dump the personal attacks.

Oh, please! Don't give me that "time to consult the echo
moderator" line. Someone as "suspicious" as you are (please count
the number of times you use this word when posting me); but not
by any means "accusing" needs more help than you can get from a
FIDO Electronics conference, or moderator for that matter. By
even suggesting that you are thinking of calling upon the
moderator, suggests that you are of a mind to accuse me of
something. Feel free to consult with the moderator at any time
you please. I have done nothing wrong.

 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?

Absolutely, where did you think I get my numbers? Make them up?
Too many people here have see how I document my work. You are
telling me that you are an expert with this math, as such I feel
no need to work the equations for you.
In other words; sharpen your own pencil.

 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.

Very good. Go to the head of the class.

 TS> Since ionizing voltages are fairly standard calculations,
 TS> assuming predictable humidity, airborn dirt, and temperature
 TS> conditions, I'd guess the previous voltage guesses may be
 TS> close, but the peak currents exceed steady state averages by
 TS> the inverse of the duty cycle, which the 2 MW figure for 10
 TS> KVA implies averages 0.5%.

Not bad! You are pretty warm. That is exactly how I obtain my
megawatt range peak powers. This is why quenching the main system
spark gap is essential. The longer the main spark gap fires, the
greater that ".5%" figure gets, and your peak powers are reduced
correspondingly. See, I knew you could do it!!!

 TS> That still doesn't say much about how much variation is
 TS> normal from a mathematical average. Would that be a range of
 TS> perhaps 1 to 30 amps, or is there any practical means of
 TS> estimating within any test setup you or Tesla have tried?

That variable may controled, and yes it can be measured with a
current transformer on the primary.

 TS> As to the 6.78 MHz or other ISM frequencies, I strongly
 TS> suspect that imitation lightning is inherently too wideband
     ^^^^^^^
 TS> to possibly be confined to such allocated legal spectrum.
                                               ^^^^^
Boy you are full of "legal" "suspicions" . Just look at the
>                    ^^^^^  ^^^^^^^^^^^^
highlighting I have used in quoting just ONE of your posts!!!
BTW, where did you come up with this frequency???

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

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

 TS>  ! Origin: Charges filed under Ohms Law!  (203)732-0575 BBS
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Please look elsewhere to file your charges.


  Date: 06-19-94  23:29
  From: Richard Quick                           
    To: Terry Smith                              
  Subj: 10KVA Tesla Coil

Just a recap of your method of communication:

 TS> I haven't accused you of anything...

 TS> ps:  On thinking about FCC considerations, it's pretty
 TS> likely that these Tesla coils are highly in violation of
 TS> today's rules and regs.

 TS> strongly suspect, after considering some FCC implications,

 TS> Tesla devices and technology.  The more they're discussed,
 TS> the more I suspect... about their becoming a legal
 TS> "forbidden fruit"

 TS> Regardless of legal implications...

 TS> .... they can't operate legally under today's R&R.

 TS> the "unintentional radiation" question that it's impossible
 TS> to operate a large Tesla coil legally

 TS> this may be a more blatant "illegal use of FidoNet" than the
 TS> kids holding criminal discussions of CB linears.  Perhaps
 TS> it's time to consult the echo moderator for an opinion on
 TS> how he'd suggest this thread continue.
 TS> Please dump the personal attacks.

 TS> imitation lightning is inherently too wideband to possibly
 TS> be confined to such allocated legal spectrum.

 TS> are legal options possible to shift the mode of old ideas

Of course it is clear you want me gagged, but you will maintain..

 TS> No harm meant

Let me make a suggestion before parting today. If you choose to
post me by name again on this subject, would you be so kind as to
tone it down some. You have maintained that you are not accusing
me of anything, but to me the tone suggests otherwise.

I am certain that since you are most definately not accusing me
of anything, and you don't mean any harm, most of your statements
and quotes above are corrupted and/or taken out of context.

What you feel perhaps to be "personal attacks" (questions such as
"do you have a day job?") are quite relevant as I deal with Tesla
facts. Crackpots have already wasted too much of my valuable time
on subjects about which they have no knowledge. Most of the
crackpots who have crossed my path don't work during the day, and
have plenty of time to waste mine.

Tesla Coiling is a legal, educational, and entertainable, hobby.
Like many powerful tools and instruments; there is a potiental
for misuse and abuse by unscrupulous persons. Safe and proper use
requires education.


  Date: 06-19-94  11:34
  From: Jamar Neal                      
    To: Richard Quick                     
  Subj: Re: Tesla

> 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)



  Date: 06-18-94  19:21
  From: Bob Patten                            
    To: Richard Quick                          
  Subj: Tesla Coils

-> 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,       BP
! Origin: Bashful Pervert BBS  (305) 472-7715  (1:369/120)

  Date: 06-19-94  22:04
  From: Don Kimberlin                
    To: Richard Quick                  
  Subj: Tesla Coils

RQ> DK> ...all the more important then, in the case of those who
DK> would build Tesla coils today, that they understand how
DK> to make really high-efficiency ones, then, eh? I know an
DK> awful 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. The output here is a low voltage RF current at quite a
RQ>few rms amps. The signal seems to conduct better than it
RQ>radiates, so just make sure your ground path is equipped for
RQ>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?
 Concord,N.C. (704)792-9241  (1:379/37)


  Date: 06-14-94  16:51
  From: Richard Quick                            
    To: Michael Scott                            
  Subj: Tesla Coils, Video

Mike,

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

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.

                                     Thanks again;


                                     Richard Quick


  Date: 06-17-94  20:20
  From: Richard Quick                  
    To: Sjoerd Schaafsma                  
  Subj: Tesla Coils, Video

RQ> If you have any problems, questions, comments, corrections,
RQ> etc., please post me. Since your tape was sent out of the
RQ> country I would appreciate it if you would let me know when
RQ> it arrives.

 SS> Thanks a bunch Richard, I'll let you know...

That turn-around was fast. This lap around should catch you with
my video in your mailbox.


  Date: 06-14-94  16:56
  From: Richard Quick                           
    To: Sjoerd Schaafsma                          
  Subj: Tesla Coils, Video

Sjoerd,

Your video tape was posted this morning too. Since you are not in
the states it will be a week or more before it arrives, though I
did pay for first class air service. I included the disk with the
text files.

If you have any problems, questions, comments, corrections, etc.,
please post me. Since your tape was sent out of the country I
would appreciate it if you would let me know when it arrives.

                                     Thanks again;


                                     Richard Quick


  Date: 06-22-94  15:49
  From: Richard Quick                
    To: Jamar Neal                     
  Subj: Tesla

 > Tesla's system was universally adopted in one country after
 > another, yet Edison gets credit for lighting the world.

 JN> So Tesla was the brains behind Westinghouse? 

Oh yes, absolutely. A very good book on the subject is published
by Barnes and Nobel:    TESLA, Man Out of Time 
Margaret Cheney, 1981, published by Dorset Press, ISBN 0-88029-
419-1; available from Barnes & Nobel, 126 Fifth Ave., New York,
NY, 10011, tel:201-767-7079. 320pp, hardcover, catalog #1611151,
$7.98 US. 

They carry another Tesla title: The Inventions, Researches &
Writtings of Nikola Tesla, 1893, N.Tesla (edited and prefaced by
Thomas Commerford Martin), ISBN 0-88029-812-X, published by
Barnes & Nobel (1992 second edition). 512pp, hardcover, catalog
#1774447, $9.98

 JN> I have read a few books on Edision and it was never          
 JN> mentioned that Tesla worked there (I have to pick my book    
 JN> better :-)) Edision often gets credit for lighting the       
 JN> world...but that is because of the light bulb.  I think most 
 JN> people know that his DC idea lost out.   

Well the second book I listed, by Tesla, is a transcript of some
of his lectures. It pretty much lays out his idea of
generator/motor power transmission systems and covers some of his
lighting work. The Complete Patents will show parallel
development in mechanics and electromechanics.


  Date: 06-21-94  20:41
  From: Richard Quick                           
    To: Bob Patten                                 
  Subj: Tesla Coils

 BP> I'm a real novice at this and need to sort out a lot of
 BP> info and get a better understanding of it.  Today, I         
 BP> received in the mail a package from the Int'l Tesla Society  
 BP> which included a comprehensive listing of the publications   
 BP> they have available.  I would imagine you are familiar with  
 BP> what's available and wonder if you have any further          
 BP> recommendations.  At this point, I'm not sure if I want to
 BP> build the conventional spark gap type coil or go for a tube  
 BP> type...  Cost and availability of parts are prime factors..

I wish I could recommend the definitive book on Tesla coiling,
but I have read them all, and I still have not read IT.

But if you want to start for next to nothing you should wind a
coil and fire it from a spark excited tank circuit. This is
definately the way to go for a buck novice. A good tube tank
circuit will run quite a few bucks over what a good spark excited
tank circuit will cost. You can start both at the same place by
winding a 4" coil with a resonate frequency of around 450 kHz, or
preferably a little higher.

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

Buy at least 1-1/4 lbs (~1000 feet in length) of #24 double
Formvar (enamel) covered magnet wire. Wind the wire on the coil
form. The windings needs to be tightly spaced, no gaps, and no
overlaps: the winding should start 1" above the bottom of the
coil form. #24 magnet wire winds about 46 turns per inch (TPI),
the winding should be 19 inches long with ~874 turns, and use up
about 915 feet of the wire. The winding should stop about 1"
below the top of the coil form.
 
Use tape, hot glue, or clear epoxy to affix the top and bottom
turns of the coil winding. Never drill holes or introduce wire
inside the coil form. Once wound, the windings should be sealed
with several coats of polyurethane or clear two-part epoxy paint.
After the windings are sealed, I cap the top and bottom of the
coil form with disks of plexiglass bedded in epoxy. 

This coil is modern. It offers the maximum inductance per unit
volume of coil form in a high Q design. It will work very well in
a spark, or tube, driven tank circuit of moderate power.


  Date: 06-21-94  22:18
  From: Richard Quick                         
    To: Don Kimberlin                           
  Subj: Tesla Coils

Talking about Tesla Coils...

 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.  

Yes. A Tesla coil is a resonate transformer. The "transformer"
part means that the system involves energy exchange by induction.
But it is not simply producing a "maximum induction field", but
of producing a field of proper intensity and shape around a
resonate inductive structure (coil). It boils down to proper
mutual inductance between primary and secondary, known to coilers
as "the coefficient of coupling".

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

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

 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.  

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

 DK> I grew up down in Florida's "lightning alley" and have       
 DK> repeatedly had to try to teach the lesson about
 DK> 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.

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

 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?

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

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

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


  Date: 06-22-94  01:06
  From: Terry Smith                              
    To: Don Kimberlin                            
  Subj: Tesla Coils

RQ>The goal should always be maximum efficiency. This is the
RQ>major

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

 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,

I always thought emphasis at RF on radiated rather than induced
fields was chosen because of the square versus cube function
signal decline with distance.  Induction, conversely, seems
preferred for closed system industrial processes.

 DK> ...My own background in high-powered radio (and Terry
 DK> Smith's,

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

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

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

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)


  Date: 06-21-94  17:07
  From: Mark Conway                               
    To: Richard Quick                            
  Subj: crossed wires

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.
 
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)


  Date: 06-22-94  18:54
  From: Bob Patten         
    To: Richard Quick                    
  Subj: Tesla Coils

-> 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)

  Date: 06-23-94  21:17
  From: Roy J. Tellason                   
    To: Richard Quick                       
  Subj: Tesla Coils

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>

  Date: 06-23-94  18:53
  From: Richard Quick                           
    To: Terry Smith                           
  Subj: Tesla Coils

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. 

  Date: 06-19-94  11:34
  From: Jamar Neal                             
    To: Richard Quick                            
  Subj: Re: Tesla

> 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)


  Date: 06-18-94  19:21
  From: Bob Patten                                
    To: Richard Quick                                
  Subj: Tesla Coils

-> 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)


   Date: 06-19-94  22:04
  From: Don Kimberlin                      
    To: Richard Quick                       
  Subj: Tesla Coils

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?


  Date: 06-24-94  16:37
  From: Richard Quick                             
    To: Mark Conway                                
  Subj: crossed wires

 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.


  Date: 06-22-94  14:51
  From: Don Kimberlin                   
    To: Jamar Neal                          
  Subj: Re: Tesla

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)


  Date: 06-24-94  16:54
  From: Richard Quick                             
    To: Roy J. Tellason                            
  Subj: Tesla Coils

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.

  Date: 06-24-94  07:50
  From: Dave Mcknight                             
    To: Terry Smith                              
  Subj: Tesla Coils

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)


  Msg#: 7532            Rec'd                        Date:
06-24-94  10:47
  From: Don Kimberlin                                Read: Yes   
Replied: Yes
    To: Richard Quick                                Mark:        
            
  Subj: Tesla Coils


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)



  Date: 06-23-94  18:53
  From: Richard Quick                         
    To: Terry Smith                             
  Subj: Tesla Coils

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. 


  Date: 06-24-94  16:54
  From: Richard Quick                              
    To: Roy J. Tellason                           
  Subj: Tesla Coils

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.



  Date: 06-26-94  16:47
  From: Richard Quick               
    To: Don Kimberlin                     
  Subj: Tesla Coils

... 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.

  Date: 06-24-94  23:10
  From: Don Kimberlin                           
    To: Terry Smith                             
  Subj: Tesla Coils

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)


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


 -=> 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. 


  Date: 06-24-94  14:56
  From: Terry Smith                               
    To: Richard Quick                             
  Subj: 10KVA Tesla Coil

 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)


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

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)


  Date: 06-26-94  09:30
  From: Michaelj Scott                          
    To: Richard Quick                            
  Subj: TESLA COILS, VIDEO

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)


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

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)

