Re: FCC

["Ed Phillips" <evp-at-pacbell-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

> Because a tuned coil concentrates its power in a narrow
> frequency band. An untuned coil causes wideband splatter with
> all the input power covering a range of frequencies. I too
> have observed this.
> 
> Regards,
> Malcolm
> <snip>

	Even a properly tuned coil will put out interference over a very broad
band.  The tuning will help avoid "dumble humps" in the spectrum if the
coupling is also set low enough, but the bandwidth of this damped wave
is still quite large (10% at the 3 dB points at the very best),
particularly when heavy streamers are loading down the secondary and
reducing the Q to nil.  It would be possible to estimate the bandwidth
of the secondary voltage by observing the waveform as it decays.  I'm
too lazy to calculate things now, but sure my old radio books have
correct formulae.

	The smallest bandwidth one could hope for would be that of a primary
circuit with no secondary at all.  Of course, the leads to the gap will
have resonances up through the VHF range at least, so plenty of TVI is
possible if the layoud favors radiation.

Ed