Re: RF field strength - SSTC coils

["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>

Look back in the archives for RF safety.. there were some posts a few 
months back discussing likely RF levels, given voltages, etc.

You're in the "near field" for sure, so antenna equations, or inverse 
square law isn't going to do you much good.  Your limits are going to be 
the E or H field, not the specific absorption... The SAR numbers are more 
for higher frequency which would be unevenly absorbed depending on 
proximity to the antenna (of, e.g., a cell phone or HT)

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