Bryan - 

Not sure where you are located, but the microseisms are high right now.  You
can check out a Navy web site that shows ocean wave height around the world,
from current, to projected wave height for 144 hours in the future.  Ocean
waves are a big contributor to seismic noise in the 6 to 10 second period
noise.  The link to web site is
https://www.fnmoc.navy.mil/PUBLIC/WAM/all_glbl.html

More information can be found with the ALBUQUERQUE SEISMOLOGICAL LABORATORY
(ASL) publication, OBSERVATIONS AND MODELING OF SEISMIC BACKGROUND NOISE.
This can be downloaded from the following link
http://aslwww.cr.usgs.gov/Publications/pdffiles/asl93-~1.pdf

Another quick reference for microseisms is the Lamont-Daugherty Cooperative
Seismic Network (LCSN), near New York City.  Their link is
http://www.ldeo.columbia.edu/cgi-bin/LCSN/WebSeis/24hr_heli.pl

Hopefully these links will help you in making determinations of your seismic
activity.  As you can see the microseisms are high on the LCSN web site, and
I am experiencing high microseisms at my location, about 30 miles west of
Tucson, Arizona.

Bob Hancock
Tucson, AZ

-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of 1goss@...........
Sent: Sunday, April 03, 2005 15:02
To: psn-l@..............
Subject: Re: noise

I am having problems with noise during the night. Oddly it starts about
9:00pm and ends about 11:00 am.

9:00pm WinSDR screenshot  https://home.comcast.net/~bryangoss/noise9pm.jpg

11:00am WinSDR screenshot  https://home.comcast.net/~bryangoss/noise11am.jpg

I think these pictures will explain much more than I can.

I thought it could be because the shop has a concrete floor and the air in
the shop heats up to aournd 70F during the day and cools to around 36F at
night. I believe the slower cooling of the floor during the night could be
causing  convection in the box. I tried to seal the box off and covered it
with a blanket but that did not work. Could it be caused by the temperature
change in the mineral oil and the vertical dampener?

I ran FFT but to be honest, I'm not sure how to read it.

Thank you for any help you can offer.

Bryan S. Goss





__________________________________________________________

Public Seismic Network Mailing List (PSN-L)