From: "Malcolm Watts"
Date: Mon, 21 May 2001 09:16:53 +1200
Subject: [TSSP] Something of Interest
Hi all,
Being the type to get bored easily when there is nothing to
do and not wishing to start a major series of expts (for which I'm
currently ill-equipped laboratory-wise at the moment), I played
around with a couple of resonators driven CW from a very low Z signal
generator and scope. Briefly, two of the resonators were around 20"
long, one with a diameter of 9" and the other about 4.5" (about 700
turns closewound), and the third resonator about 4" but wound with
about 1700 turns of rather finer wire. I don't have the details with
me at work so please forgive the lack of specifics. What I observed
will give rise to a series of expts and msmts when I get back from
the States. The generator is capable of 3VRMS with a source impedance
of 0.5 Ohms resistive. Among other things, I noted a *drop* in Q when
placing a terminal on resonator #3 (usually one sees a rise and I
infer skin/proximity losses are most probably responsible due to the
small wire size) but of all three, this was the best radiator with no
terminal. I placed a 2' fluoro lamp on each resonator in turn and
with this particular resonator, the lamp lit for 3 or 4 resonant
modes (higher order). The lamp could be ignited by holding about 6"
away from the tuned coil and was still running 3' or so away with
some judicious retuning of the sig gen. There is some interesting
data to be mined out of all this and I expect some interesting
running results as well, both with and without terminals. I decided
to flag this as I won't have an opportunity to do anything about it
for several weeks and someone else on the list might. While
conventional wisdom concentrates on high secondary Q's, there is some
really interesting stuff to be gleaned from secondaries that pack a
lot of L into a relatively small volume. Tx line effects abound.
Regards,
malcolm
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.