[TCML] Is my 10" Tesla Coil Illegal ?
g.peterson at tfcbooks.com
Fri Jan 29 16:13:57 MST 2010
"I don't fire up my 10" TC very often anymore [because] I worry it might be
Possession of a Tesla coil here in the United States is perfectly legal. It
is also quite legal to operate a Tesla coil here, provided you don't cause
harmful interference. If you do cause harmful interference, even if you are
not aware of it, you have crossed the line and are subject to sanction by
the FCC. It makes no difference whether your machine is, or you consider it
to be an "intentional radiator" an "unintentional radiator" or an
"incidental radiator" the rules are clear:
CFR 47 Part 15.5 (b) Operation of an intentional, unintentional, or
incidental radiator is subject to the conditions that no harmful
interference is caused and that interference must be accepted that may be
caused by the operation of an authorized radio station, by another
intentional or unintentional radiator, by industrial, scientific and medical
(ISM) equipment, or by an incidental radiator.
> . . . that the FCC does care is probably right, even if a TC is an
> incidental radiator. However, there's no requirement to meet any
> particular technical standards (homebuilt provisions in 15.23, for
> instance) other than "good engineering practice," whatever that might be
> for Tesla coils.
If the problem is, in fact, "radiation" then a simple way to avoid it is to
self-certify your machine as a non-radiator, or at the very least measure
the radiated power and if necessary take appropriate steps so that its RF
spectrum noise output falls below some pre-specified level.
> A battery-operated radio will tell you about how far [or how much] you're
> radiating. . . .
Better yet is to test the radio-wave emissions of the Tesla coil following
guidelines set forth in "FCC Methods of Measurements of Radio Noise
Emissions From Industrial, Scientific, and Medical Equipment" (see
2.2 Measuring instrumentation
Radiated and conducted measurements shall be made with a radio noise meter
that conforms with the American National Standard Specifications for
Electromagnetic Interference and Field Strength Instrumentation 10 kHz to 1
GHz, ANSI C63.2-1980. Alternatively, a spectrum analyzer may be used,
provided the results obtained can be accurately reproduced with a suitable
radio noise meter and that it is used, when necessary, with appropriate
accessories to insure sufficient sensitivity and overload protection. . . .
Accessories needed would depend upon the measurement situation and could
include preamplifiers for sensitivity improvement, filters and/or
attenuators for overload protection, and additional quasi-peak detection
circuitry (for testing RF lighting devices).
The following antennas shall be used for measuring the field strength:
--below 18 MHz shielded balanced loop
--18 to 30 MHz shielded balanced loop or calibrated tuned half-wave dipole
--30 to 1000 MHz calibrated tuned half-wave dipole
--above 1 GHz broadband linearly polarized horn antenna
2.2.5 Antenna height variation
The measurement antenna must be varied in height above ground to obtain the
maximum signal strength.
For a loop antenna. The antenna height shall be set at around 2 meters.
Care should be taken to assure that readings are not taken in nulls.
----- Original Message -----
From: <gary350 at earthlink.net>
To: "Tesla Coil Mailing List" <tesla at pupman.com>
Sent: Tuesday, January 19, 2010 10:56 AM
Subject: [TCML] Is my 10" Tesla Coil Illegal ?
This time of the year when the air is cold and the humidity is extremely low
static electricity is very high I get shocked every time I get IN or OUT of
my SUV, take off my jacket or put on my jacket. If I move the blankets in
bed at night I see all kinds of sparks. It is perfect for firing up my
Tesla Coil and getting some very long sparks. But I worry that this might
be illegal. My 10" TC makes 12 foot arcs I can make a 27 ft circle of arcs
and sparks in the back yard with the 3 ft top load. It makes every motion
detector light and every security alarm system go off in a 4 block radius
around my house. After dark I can see motion detectors lights going on/off,
on/off, on/off, on/off, on/off, in all directions as far as I can see. My
automatic garage door and all the neighbors garage doors are freaked out
going up/down, up/down, up/down, up/down, up/down, up/down, over and over.
I can hear security alarms in all directions. I road my bicycle through the
neighbor hood and I can find alarm systems going off 4 blocks away in
several directions from my house. It totally distroys TV and it makes no
difference if you have cable, satallite, or antenna TV is totally wiped out
all reception for several blocks. I don't fire up my 10" TC very often
anymore I worry it might be illegal.
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