TSSP: List Archives

From: Paul
Date: Fri, 27 Oct 2000 08:34:42 +0100
Subject: [TSSP] Sonotube losses

Terrell W. Fritz wrote:

> The Sonotube burns quite nicely so the fire retardant idea is out.

> The present idea is that water absorbed into the little fibers in
> the cardboard is causing the high loss.  Does this sound reasonable?

Maybe. Bit out of my field, but let me guess that the water by itself
won't absorb much at these low frequencies, but if some ionic compound
becomes dissolved in it... not an obvious fire retardent, but there
might be lots of other things in it, anti-fungus, bleaching,
pH balancers, 

>  I will microwave a chunk tomorrow

Why not run your 900W CW into the coil for a few hours. Measure
the Q every 30 mins, say, and see if it's creeping up as any dampness
is driven out by the 'microwaving'.

At the end of the run, 'steam' the tube over a kettle and remeasure
the Q to see if its dropped again. 

That would confirm that the water is dissolving something in the tube
and making a lossy conductor.

Then you could cram a piece through the food mixer. Soak the 
crumbs in water overnight. Filter the water, evaporate, and crystalise
it out to see how much water soluble stuff was originally in it.

Then all you need is a tame chemist to analyse the residue!

Cheers,
--
Paul Nicholson,
Manchester, UK.
--


Maintainer Paul Nicholson, paul@abelian.demon.co.uk.