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Re: Tesla Coils and Lamp Tests -

Hi John and All,

At 01:06 AM 2/23/99 +0000, you wrote:
>
>  Terry, All -
>
>  I believe that Terry and others are doing a great job in running the Tesla
>List. For this reason I hope that readers will understand the following is a
>sincere effort to  keep the record straight and not a criticism of how the
>List is being managed.

No Problem there.

>
>  First of all I am not or ever was an advocate of "free energy". In fact my
>past posts have always been to try and explain why this is not possible. I
>have also tried to point out the differences between energy and power
>because these two words are often misused. I am also not an advocate of
>using Tesla coils to power anything at this time because we apparently have
>plenty more to learn regarding how a Tesla coil works. 

I didn't mean to imply you personally were a "free energy" advocate or any
thing like that.  Nor do I mean the such fun stuff is bad or anything.
Just that this subject has a habit of getting responses that are really
better suited to the USA-TESLA list than ours...  

>
>  My understanding of the Tesla coil operation. The following will be new to
>most and maybe all of the members of the List because I have not seen it
>mentioned before. Around the Tesla coil there are four "electrical" fields,
>2 are electromagnetic (EM) (Hertzian) fields and 2 are induction (Faraday)
>fields. I refer you to Terman's Electrical Engineering Handbook. The
>induction fields are stronger than the EM fields near the Tesla coil but
>become negligible a short distance from the coil. Only the EM fields are
>detectable away from the Tesla coil and continue for great distances. All of
>these are "dynamic" electrical fields consisting of both electric and
>magnetic fields. The electric fields can induce voltages and the magnetic
>fields can induce currents in nearby objects. Another story. Note carefully
>how these fields are named to avoid confusion.

Could you define each of the four fields for the sake of discussion?  These
terms are not common and I think they confuse most people on the list.
They confuse me...  I'll take a stab at it:
  
For induction fields or "Faraday" effects:
1.	The E-field or voltage per unit length field.
2.	The B-field or magnetic flux field.

For EM fields or "Hertzian" effects:
1.	RF radio waves.
2.	Those big electrical earth resonance waves Tesla dreamed of that would
power things around New York??

	
My recent tests with standing waves and such on the secondary may help
explain something.  Tesla coils are no doubt powerful RF "generators".  At
say 400000 volts and 10 amps they approach 4 megawatts in power.  However,
since the coil itself is also the "antenna", it appears to be only a tiny
fraction of a 1/4 wave length and therefor is very very inefficient at
"transmitting" RF radio type waves.  In other words, it is like chopping
off a CB radio antenna to only 1/25 of an inch.  The power is there but the
"tiny" almost point source antenna does not transmit well at all.  Of
course, Tesla coils put out a lot of RF on one's TV and such.  However, if
one were to take the TV to a 4 megawatt broadband transmitter with a proper
antenna, the RF noise would be many orders of magnitude worse than what a
typical coil radiates.  There is an obvious solution to this poor
transmitting problem, but it is probably best not to go there :-))

>
>  When someone says "electrostatic field" I understand this to mean the
>"static" electric field around the coil right after it is de-energized. At
>this time the coil is electrified for several seconds and this can be
>detected. This is a static electrical field and does not have enough energy
>to light a lamp except maybe an LED for a few seconds when held near the
>coil. It can also briefly operate an electrostatic motor. The operation of
>an electrostatic motor when the TC is energized is another story. The forces
>from electrostatic fields are not the same as forces from dynamic fields.

By "electrostatic fields" I have always meant the E-fields that are
generated in real time at the Fo frequency in the area directly around the
coil that accounts for energy storage in the secondary capacitance.  I have
never given the little static charge left on the secondary after the coil
is turned off much thought at all.  There should not be any great
theoretical challenges there? ;-)

>
>  Hertzian fields are the ones that radio engineers work with.  The Faraday
>fields are normally only of interest to electrical engineers because these
>fields exist at both low and high frequencies and are involved in the design
>of generators, motors, and transformers. Tesla coil engineering involves
>both radio and electrical engineering.

I have always felt that the "Hertzian", or true RF signals, are fairly
insignificant compared to the "Faraday" fields.  I am sure a good (or not
so good) radio engineer could turn a TC into a great RF transmitter in a
few minutes, as was done in the early days of radio.  However, I would
think that would be the last thing one would want to do.  Having your TC
broadcast around the world may be neat for a day or two.  But, when the
federalies show up with their pink slips and summonses, a simple HAM rig
and a license would have been a far better choice!  I know of one coiler
who has found the FCC at his front door.  He describes the whole summons,
court, fine ($1000), eviction (landlord didn't like seeing Feds with a open
the door NOW! warrant)... thing as being "BAD!"... 

>
>The Hertzian fields are capable of lighting Malcom's LED's when using a
>tuned circuit with an antenna to collect as much energy in the EM wave as
>possible. 

Actually, if you tune only one frequency, you would reject the vast
majority of the power.  A simple antenna will delivered the full RF
spectrum to the LED which will give the most power and most light if one is
just using the ambient RF "noise" in the area.  It may provide a beneficial
impedance transformation effect however...

>The size of the receiver antenna to collect enough energy would
>depend on the transmitter power and distance from the radio transmitter
>antenna. However, the energy available is very small and usually for normal
>use the energy has to be amplified using local energy. There were no Faraday
>fields from the radio transmitter at Malcolm's location.
>
>  Because Reinhart's 25 watt incandescent lamp uses much more current and
>energy it must be very close to the Tesla coil. These currents for the lamp
>are induced by the induction (Faraday) fields around the coil because the
>Hertzian fields are too weak. Only a 12 inch wire was necessary to induce
>the proper amount of current to light the lamp. No tuned circuit is
>necessary because the induction fields are strong enough to light the lamp
>when near the coil. This is a closed circuit which includes the secondary
>wiring that is grounded and also magnetically coupled to the 12 inch wire..
>
>  I agree that Richard's and Alex's experiments with the disconnected coil
>is really neat. Do they know if the energy and sparks are from the Faraday
>or  Hertzian fields around the Tesla coil? A conductive sheet between the
>coils would stop the effect in either case.    

I would guess Alex's system used "Faraday" effects since the TC should be
far less efficient at putting out true radio waves.  Although, the power is
great and the distance is short... Even a point source antenna puts out a
little RF.  But the energy they were getting appears too great not to be a
"Faraday" effect.  The fact that the second coil was high Q allows the
energy to build up a bit too and thus its implications in the magnifier
theories.  Some more fun work could be done here!

>
>  I like Terry's illustration of the field mapping using field sensing
>antennas. The voltage times the amps giving 400 KW is a good example of
>Tesla coil operation. This is pulsed power so the energy in, say, a 10
>microsecond pulse (100 KHZ) would be 4 joules. At 120 breaks this would be
>480 joules per second. This is certainly enough to light Reinhart's 25 watt
>lamp even with very low efficiencies. The brightness would depend on the
>distance from the coil. The brightness would reduce quickly as the lamp is
>moved from the coil because the inductive fields become negligible a short
>distance from the coil.

I Like my illustration too :-))  It does simply get the idea across.  Even
though it "looks" like nothing is there, there really is SERIOUS energy in
the air space around a Tesla coil.  Objects placed in this area will find
lots of voltage and current buzzing around.  It would be interesting to
study how various "cheap" electronic devices behave in this area.  It would
be an extension of the habit auto companies have of driving their
electronically controlled cars under high power transmitter antennas to be
sure the electronics will not be affected by the extreme fields.  Perhaps a
small business opportunity there.  I can't imagine any thing worse than a
TC for such a test...  Watches, pagers, calculators... would all be
challenged in this zone.  My boss keeps wanting me to have a pager.  This
will definitly be its first test :-))

>
>  I agree that the frequency does not have any effect when the lamps are
>lighted by the currents due to the inductive (Faraday) fields. However, the
>frequency is very important with the LED's and a tuned circuit with an
>antenna is required when the lamps are lighted by the electromagnetic
>(Hertzian) fields.

I would wonder if one were trying to light an LED at a distance, if another
tuned coil or just a wire with an equal RF "profile" would give the
brightest light?

>
>  The question of whether the fluorescent lamp is lighted by Hertzian or
>Faraday fields I will leave up to the members of the List. However, it
>should be noted that relatively large currents are still needed.

I vote "Faraday".  Richard Hull (I believe) has walked around the
neighborhood with a radio receiver and has shown that the RF dies out at
about a block.  Considering that he is trying to pick up multi-megawatt
transmitter with a modern super whatever-dyn receiver.  A propagation
distance of one block shows that the antenna is really really poor!!

>
>  Note that the above electrical field differences are what Tesla was trying
>to point out to the electrical people of his day. Tesla said that his world
>electrical system would not use Hertzian waves.

I submit it could NOT use "Faraday" effects due to the massive losses.
Thus, we all are using wall plugs :-)  I have always wondered if, in the
middle of the New York project, it suddenly became apparent to Tesla that
the basic theory behind that beast was in effect "all screwed up".  It
seemed that the brakes got slammed on pretty quickly.  Eventually, perhaps
in latter years, Tesla must have realized what was wrong.  The New York (ok
I can't spell Wardercliffe or whatever :-)) seemed to be a sudden halt to
Tesla's work in this area.  I wonder if this was the great turning point
when he saw that the world electrical system was not going to work?

>
>  I do not see how this subject can possibly go off to "free energy" but
>then coilers are a resourceful lot and moderators have a job to do` :-(

I am probably just making it worse!  But there IS some important
information here that should be understood.  We can tolerate a little "far"
theory as long as we all understand it's practical uses to us.  Since RF
transmissions from Tesla coils can cause us all kinds of problems, this
subject really is important.  

	Terry

BTW - It is not hard to figure out how to get better RF output from a Tesla
coil.  Even a small coil can put out many megawatts of RF that could
broadcast thousands of miles.  However, the FCC can spot, triangulate, and
know where a coil is within about a block in a fraction of a second if they
are looking for it (the miracle of modern electronics).  If you are big
enough, their automatic equipment will find you and print your location for
them first thing in the morning.  Your neighbors will be glad to point them
to your front door (it's not like they will be busy watching TV or anything
:-)).  It is far better to do everything possible to avoid their attention
and use RF theory to reduce RF transmissions to the absolute minimum.  In
other words, don't experiment with Tesla coil RF transmissions unless one
can do it without getting into trouble!  A little tweaking could turn a
coil from a little blip into a big RF interference investigation that would
not help our hobby...  So if anyone wants to experiment with such things,
please be careful not to become the RF equivalent of a super nova.

>
>  I believe this is a new approach to the operation of the Tesla coil so
>comments are welcomed.
>
>  John Couture
>
>---------------------------------
>
>At 03:32 PM 2/20/99 -0700, you wrote:
>>Original Poster: Terry Fritz <twf-at-verinet-dot-com>
>>
>>Hi John,

snip.................