Silly question Larry. Are you sure the noise is not being caused by spiders, also 
known as spiderquakes, or some other insect getting inside the enclosure? I guess it 
could also be air currents inside the enclosure. Do you have a lot of free air space 
inside your sensor box?

Regards,
Larry Cochrane
Redwood City, PSN

On 6/19/2012 11:54 AM, Larry Conklin wrote:
> I have an SG sensor that has intermittently had serious noise problems,
> literally for years.  Mechanically, it is very similar to the design
> that is shown on Larry's PSN web site, and it uses Larry's electronics
> board, which I believe he is no longer selling.
>
> When the thing is running properly I've been quite happy with it. But
> occasionally, for reasons I have never been able to pin down, it
> exhibits extreme low frequency noise, to the point where it is basically
> useless.  The current episode began with the system running very well,
> but it was in need of leveling, which I've typically need to do every
> couple of weeks or so.  Before I adjusted the leveling screw, it was
> quiet.  After messing with it it became extremely noisy.  So, you'd
> believe that it was some sort of mechanical problem, right?  And I've
> had several other episodes that began the same way.  This time, when I
> brought it upstairs on the bench, I did in fact discover that the lock
> nut on the leveling screw was loose, and I "fixed" the problem by
> re-tightening it.  Ran pretty well for a week or so thereafter, but not
> really as quiet as it should be.  Then, it spontaneously got quite noisy
> again, interspersed with periods where it ran ok.
>
> I have a lot of other history with seemingly mutually exclusive
> symptoms/probable causes, but the bottom line is I don't have a clue
> what is really going on.  I'm tempted to believe that there is something
> subtle wrong with the electronics board, but in past attempts to trouble
> shoot it, haven't been able to find anything.
>
> If there is anyone out there who has one of Larry's SG boards that
> they're willing to part with, I'd be interested in buying it.  If for no
> other reason than to rule out the board as the source of the problem.
>
> For the curious, I have a little web page that I dump drum reports up to
> daily. The report for today (so far) shows a particularly noisy day, but
> does include the quake that happened in the Aleutians this afternoon.
> The page also shows drum reports from the day this round of the problem
> started.  The day started just fine, until the big transient that
> resulted when I went down and adjusted the leveling, at which point all
> hell broke loose.  You can also see the consequences of two subsequent
> leveling adjustments later in the day.  After that data was recorded, I
> didn't mess with the thing for maybe a week, until I finally got around
> to taking a closer look at it, at which point I realized that the
> leveling screw was loose and re-tightened it.
>
> I'd be very interested in anyone's thoughts on this problem.  The link
> to my web page follows:
>
> http://home.roadrunner.com/~lwconklin/
>
> Larry Conklin
> Liverpool, NY
>
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