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Re: Variable Capacitance and Inductance
Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>
> Hi Dave,
> With one _not_ tuned by crystals I routinely leave it
> on, volume down, turn it up, and there is the BBC on
> SW, 'just where i left it'. With another such, even
> older, i was listening to 'Radio Australia' (Properly: ABC
> Australian Broadcasting Company But that confuses people
> in the US, with the OTHER ABC) one day. Next day i snapped
> it on and there they were. (Both to a site in Eastern MA,
> Just because change _can_ happen does not mean change _will_ happen.
> It could very well be that your turn on your radio someday when
> there is a geomagnetic storm and you get a different station.
It won't. Geomagnetic effects, while strong, are not
that strong. Solar effects can change which transmitter
is received (cf 'skip', 'ionosphere' in a good text)
but not by changing L or C.
(Hint: there is a good storm on right now, and for the
next 24 hours....)
> Perhaps also, the frequencies you are listening to would never be
> changed due to the inductance values used in the set's oscillator.
> Tesla did not claim a small electronic inductor would have a great change in
> inductance. His claim was for a large tin foil ball wrapped around a hollow
> wooden form and dangled around 100 feet off the ground. And the claim he
> made for this large ball was that there would be small changes along the
> order of 1.6%.
I believe Malcolm commented on the details.
> The 50% per foot claim was specific to being inside a damp wooden building
> using the large tin foil ball.
Repeat the exercise, using a modern meter.