EMI/RFI (Re: TESLA COILS are ILLEGAL!)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

> I am a recent first time coiler and my research led me to this data
> which may or may not be entirely actuate

> An ungrounded Tesla coil is basically the same thing as a 1/4 wave

> spark gap transmitter...

	Basically differnt:
	The transmitter has an aerial/antenna.  And is grounded.

> used in early radio... and made illegal in or around 1927....
> I not a ham radio guy... but Im pretty sure its ok to transmit

> in certain bandwidth ranges(the very very low unused

	There are LF License Free bands.  All freqs are used for
	SOMEthing.
	AND Tesla coils are nto real good a staying on one
	freq.  (CW style coils, eg VTTX, SS, etc excepted.)

> ranges Ithink...)
 
> (sort of unrelated but)
> Anyone know about Rogers Radio system for transmitting Radio

> through the ground...
> Used heavily in world war 1

	WWI used a range of 'undergounrd wireless' systems.

> or 2 not sure which, but military posts would
> set up camp and dig a hole to bury their antenna...  One of

> those forgotten inventions...(or maybe hushed up)
	Simply not very effective.  Same power, etc, gets

	more coms done with conventional radio.  For some
	special purposes (aving, mining, there are
	applications.)


> A grounded tesla coil on the other hand is legal,

	cf other posts.  In general ANYthing can be done
	IF no interference is caused.  Grounding, if anything,
	increases the radiation.  (hint: ALL transmitters
	at those freqs are grounded....).  As noted, the
	poor radiation by Tesla systems is due to lack of a
	long radiator (antenna).

> because it drops the RF into the ground

	Whihc improves the radiation efficiency.  Also any
	'ground wire' is an antenna of sorts.


> Also I have been conducting area of field effect tests with my

>coil and a flourescent light bulb.
> I believe I have a decent ground set up. a copper pipe driven

> about 5 feet into the ground and wetted down thoroughly before

> coil operation.

	two or three more would be better.
	How long is the connection from base of coil to
	ground?

> I have yet to operate a coil without a ground (don't think I

> want to... I'm not that crazy), but all of my light bulb

> tests seem to indicate there is a major drop off in field

> effect at about 3 feet from my coil.  Meaning at about 3
> feet the light will no longer light up...

	The light bulb takes watts tolight up.  Fractions of
	a watt will interfere with other devices.

> I'm assuming all "Major" interference associated with devices

> would end at this point.

	I wouldn't.

> Considering my friend used his Cell phone at about 12-15 feet

> from the operating coil with no ill effects.

	Indicative, however the cell is on a VERY different freq.
	AND cells are 'hardened' against stray RF.


> I realize that radio frequency interference may travel a lot

> further than the electric field induction effect, but I have

> to wonder.
> How the heck was he jamming radio transmissions to a stereo????

	Nominal RF input sensitivity on receivers is in the
	MICROvolt region.

>...
> Also I'm wondering if someone is listening to the frequency

> of lightning...

	Lighting has a wide range of freqs.

> (You can hear lightning from all over the earth at a certain

> frequency)...

	My understanding is that those receivers use a range
	of freqs, and look for certain frequency combos/
	envelope shapes.

	best
	dwp

...the net of a million lies...
	Vernor Vinge
There are Many Web Sites which Say Many Things.
	-me