# Re: Tesla Coil (RF) radiation range

```Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

> > Original poster: "J Whyte by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> > <xoom321-at-hotmail-dot-com>
> >
> > I am curious how far a 6kW Tesla Coil would broadcast "Radio Frequency"
> > Anybody know?
>          To infinity, at 186,000 mi/sec, losing power inversely as the
square
> of the distance. Now if you ask how strong at what distance, then the
question
> has meaning. The exact answer depends upon the configuration of the
particular
> coil, but as an example:
>          Let's say your 6 kW coil will light a 40w fluorescent bulb to
full
> brightness at 20 ft. This is 40watts. At 40 ft you will have 10 watts, at
80 ft
> you will have 2.5 watts, at 160 ft 625 milliwatts, at 240 ft  ~156
milliwatts,
> at 480 ft ~39 milliwatts, etc.etc.

It doesn't take 40W of RF power to light a 40W fluorescent bulb.  If it did,
I'd be mighty worried about safety, because that's a power density of
several watts per square foot, which is pretty high... (nothing compared to
the sun at 100W/ft^2, but still a healthy flux)..

Sure, the tube lights up, but it's probably not full brightness.  Bringing
up an interesting experiment for someone.  Tape a light meter (or a
photocell) to a fluorescent light.  Put it in the standard fixture fire it
up and wait for it to come up to temperature.  Measure the brightness.  Now
do the TC experiment..

I'll bet that the TC is a LOT dimmer than running it off the 60Hz line.  The
TC has short high power pulses, which create short bright flashes of light.
Your eye is highly nonlinear, and bright flashes with low duty cycle (with
low total power) can appear as bright as a much dimmer light with 100% duty
cycle.  Things with LED indicators make use of this to save power.  The
other issue is of background lighting.  You can see a fluorescent tube lit
up (with usual power) in full sunlight.  I doubt this is the case with the
TC.

>
>
>

```