TSSP: List Archives

From: Paul
Date: Tue, 30 Apr 2002 20:24:59 +0100
Subject: Re: [TSSP] qvar expt4

Terry wrote:

> The Q1 dip should be real. There is an instant local temperature
> dip that is probably the computer crashing (there is no file so
> it read as zero) but Q1 and the pinger data should be fine. 
> I would guess we had a little spot rain around that time.

Ah good.  It's real clear that the big q1 dips are associated
with rain and dew, although the mechanism remains to be
figured out. 

But I'm well and truly puzzled by the behaviour of q3.  For the
others, q3 is the Q factor of the 3/4 wave overtone of the coil.
It has a curious habit of droping by some 2% to 4% for a period
of 20-30 mins.  The other two Q factors, 1/4 wave and 5/4 wave,
remain undisturbed.  This has been observed now on two different
but similar coils in the same location.  Apart from these funny
q3 blips and the rain/dew events, the q factors smoothly follow
the temperature curves.  Beats me what in the environment can be
coupling to the coil's 3/4 wave like that. Happens a couple of
times a day, roughly. No disturbance to the frequency. Most odd.
Ideas welcome!

> I am thinking of adding a top terminal next.

I see we've moved on to expt6 now, which looks suspiciously like
a toroided coil.  I'll be looking out for those q3 dips.
--
Paul Nicholson,
--


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