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Re: (meteorobs) "Electrophonic" Fireball sound nonsense
Hi Mike,
Below you calculate that the VLF power from a fireball is roughly
equivalent to one strong VLF radio station. Because there are 60 such
stations worldwide, you conclude that VLF emissions from a fireball would
be smothered by the ambient VLF background.
The very same reasoning would lead you to conclude that WWVB itself is
smothered by the ambient VLF background, because WWVB, according to your
calculations, is only a little more powerful than a meteor.
If a fireball can emit as much VLF power as WWVB, then that makes the
fireball a pretty good transmitter.
Regards, Tony
At 09:36 PM 8/14/2002 -0400, you wrote:
>I checked the WWVB website, and they state that normally nighttime field
>strengths for their transmitter are at least 100uV/m^2 over most of North
>America. Converting units, this yields power density P (uW/cm^2) =
>3.77*10^-8 * (field strength)^2 = 3.77*10^-4 = 0.000377 uW/cm^2.
>
>So, the ambient background VLF from just ONE station is already on the
>same order of magnitude as the meteor electrophonics, as I estimated.
>There are at least 60 stations worldwide with similar output power and
>many will have overlapping coverage areas, therefore it does appear the
>electrophonics will be smothered in the VLF "noise".
>
>Mike Linnolt
>
>--- "Dr. Tony Phillips" <phillips@spacescience.com> wrote:
> > At 08:27 PM 8/14/2002 -0400, you wrote:
> > >Well, I believe the 0.003uW/cm^2 RF background
> > includes all frequencies.
> >
> > To make a fair comparison, it's necessary to know
> > what fraction is VLF and
> > what fraction is not. If the ambient VLF background
> > is 0.0003uW/cm^2, for
> > example, the argument that meteors cannot rise above
> > the background noise
> > no longer holds.
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