RF field strength - estimate from E-tesla

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

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

Using the sample file that comes with E-tesla6 and changing it so that the 
primary is at the level of the base of the secondary (6" off the ground)...

It's kind of funky for the scaling (120 inches wide (I assume that's what 
it would be) you get 162 data points (1.35 points/inch)....  Anyway, 
figuring the center is at 81, and moving 48 ticks away (roughly the length 
of the coil) to 33 ticks from zero.. the field is about 0.65/per unit.. 
Now, I scale as follows:

Assume top voltage is 400 kV
Assume units are 1/1.35 inches or 1.88 cm
The field at that point is 4*.65/1.88 kV/cm or 1.38 kV/cm, or 138 kV/m....

That's a bit(!) above the ANSI/FCC 618 V/m.... But almost within the 100 
kV/m peak limit for pulsed sources.. You'd be below the peak a few inches 
away... and nobody is going to be standing 3 feet from a 4 foot tall 10 
inch TC...

You then need to average for the duty cycle... For a SSTC, that's 100%, but 
for a spark gap coil, it's going to be fairly low... <10%

At 02:54 PM 5/28/2003 -0600, you wrote:
>Original poster: "Jan Wagner by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><jwagner-at-cc.hut.fi>
>
>Hi,
>
>On Wed, 28 May 2003, Tesla list wrote:
> > Original poster: "Steven Ward by way of Terry Fritz 
> <teslalist-at-qwest-dot-net>" <srward16-at-hotmail-dot-com>
> > Dan,
> >
> > It seems that maybe since you use a signal generator to feed your SSTC, you
> > are slightly out of tune and this causes your coil to radiate so much
> > power.  My SSTC does not give me any zaps or anything when i touch ground,
> > even with a 14" spark firing off of it.  Its a feedback driven coil, so its
> > always perfectly in tune.  Maybe thats your problem?
>
>Shouldn't the radiated power be highest at resonance? As the secondary
>draws the highest power there... Same for an antenna fed by a tuned tank,
>transmit power is max at resonance. Of course, when there's no streamer
>breakout, more power is radiated, but this isn't related to the drive
>being in-tune or not. ?
>
>But anyway, it would certainly be interesting to know whether or not a
>1..10 kW SSTC could exceed the FCC specsed SAR of 4W/kg (6 minutes
>exposure?) in typical spectator distance. Not that there are any effects
>noticeable, in practice, though... ;-)
>
>regards,
>  - jfw
>
>--
>*************************************************
>  high voltage at http://www.hut.fi/~jwagner/tesla
>  Jan OH2GHR