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Re: Frequency vs temperature

Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>

Jim wrote:
> Resistance changes over temperature are going to be significant
> too.. and that slightly changes the apparent resonant frequency
> (i.e. it's really not =sqrt(1/LC) but a function of LC and R...

Yes, F observed = sqrt(1-1/(4*Q^2))/(2*pi*sqrt(L*C))

when the loss resistance doesn't couple any extra reactance into
the resonator.  It is this frequency reported by tcma. 

> The elliptical F vs T curves seem to indicate a thermal/mechanical
> time lag between parts of the system, that is, some things get
> bigger and smaller at different rates than other things

At times on the earlier experiments, some very clear lissajous
ellipses and figure-8s formed on the scattergrams.  A clear thermal
inertia effect.  

> (assuming that the error bars are reasonably sized!)

Hmm, a valid criticism is that we're not showing the error bars, only
the data. Those were left off the graphs to avoid clutter - bad enough
already with several signals to plot.  As a rough guide, the fine
noise of around 0.005% amplitude on the frequency traces, around 0.1%
on q1, and around 0.5% on q5, are the background noise of the data
capture/reduction process.

Terry wrote:
> It is interesting that q3 and q5 seem to be affected by the deeper
> dampness in the woodwork or something.

Yes, we see q1 responding instantly to rainfall/dew, whereas q3 and
q5 fall quite slowly over a period of several hours.  Then when things
start to dry out, all three recover in unison.  We've seen that in
some of the earlier experiments too.  A most interesting effect.
Can a large h/d secondary be used for some kind of tomography by
exploiting multiple modes and pings from both ends?

> I try not to breath or go near it since it is sensitive to
> disturbances

Since you live in a partial vacuum up there, I'd have thought the
odd gulp from time to time would be ok.  Thought I had a programming
error when I saw your air pressures.
Paul Nicholson