In a message dated 04/07/06, gpayton880@....... writes:

> Subj:Microseisms Discussion
> From:    gpayton880@....... (Jerry Payton)
> To:  chuckbou@............. (Boudreaux, Chuck), dwheelerf5@............. 
> (Don Wheller), tekmate@.............. (Joe Lincoln), jc3@............ (Cole, 
> John), johnstilwell@............. (Stilwell, John), ChrisAtUpw@....... (Chapman 
> Chris)

Hi Jerry,

       I suggest that you go to http://psn.quake.net/ and download the letter 
archives back to 1996. Decompress them into annual word processor files. You 
can then search for topics with 'find'. Have a good long read!

       Amateur seismology is likely to be much more of a technical challenge 
than the professional variety. The professionals choose very low noise remote 
seismic sites, buy highly developed and completely engineered seismometers at >
>$5 K per channel and have them professionally installed, often in boreholes 
to reduce surface noise.
  
    The amateur variety is very much DIY, with many enthusiasts constructing 
and then setting up their own equipment. Amateur sites are likely to be 
mediocre to appalling compared to the professional ones, so you have to learn to 
live with the limitations and to compensate for them. When making and using your 
own equipment, you learn that success is hard won and takes considerable time, 
effort and patience. You also learn how to set up the level, the period and 
the damping, how to check the performance, identify and correct problems.

    The original Lehman was OK 'for a start' back in 1976, but the 
performance was limited by the poor point / knife edge lower suspension amongst other 
factors. John Cole has pioneered the rolling contact type of suspension, which 
dramatically improves the performance and enables you to set up stable periods 
of well over 30 sec. 

    The considerable improvements in construction, suspensions, damping and 
detectors that have appeared during the last 30 years do not yet seem to have 
been reflected in a 'good simple design' available to potential constructors. 

    Now Jerry, I know that you were experiencing setup problems. What period 
are you using and is the damping set ~critical? Do you have a .psn file of the 
output?

    You can expect John's seismometer to be capable of a period of over 25 
sec, even in a poor environment. You need to achieve this sort of period or 
greater to enable you to detect the long period Love waves. If you aren't 
achieving this, you need to reduce the small angle between the suspension axis and the 
vertical. It could be that the floor is not level, that you have not 
assembled it quite correctly, or that something has got bent / damaged in transit. If 
you are NOT getting a long period, THE ANGLE IS WRONG. The screw extension on 
the top wire has very little effect on the period - it just enables you to get 
the mass at a suitable height above the floor.


> Hello Out There: PSN & ATN 
>  
> I'm throwing this out for discussion and / or experimentation to the 
> group(s) as a whole.  Anyone investigated this problem?  If it is temperature 
> fluctuations, what is it affecting, the coil, the pendulum, or what?  The fact that 
> the trace get amplified somewhat (in my case) indicates to me that it may be 
> affecting the electrical part: coil or magnets themselves?  

       You have not really described your problems well enough for us to 
advise you. 

       There is background environmental noise which changes with time, the 
weather and a wide range of human activities. Microseismic ocean background is 
usually at about 6 sec and near sine wave, which again changes phase and 
amplitude with time. This exists at all times. Wind noise can give a range of short 
to very long period signals. The seismometer is very sensitive to changes in 
the tilt angle, from a variety of sources - the walk up test. It is very 
sensitive to drafts and may also be noisy when the external temperature falls below 
the instrument temperature, due to convection. You need an insulating cover 
with all the joins 100% sealed. If the joins are not airtight, it will likely 
be noisy.

       You may also experience electronic problems due to pickup from 
transients on the house power wiring. Fridges often give problems. Some areas have 
noisy supplies. Electric trains can cause problems. Do you have the input line 
to the amplifier screened and the screen and 0V line earthed? Some of the older 
/ foreign computers had very inadequately filtered power supplies. Do you 
have a local radio transmitter, a TV station or a phone transmitter aerial close 
by?  One test is to wedge the mass in position and take a trace. 
  
       I suggest that you set the recording for a 24 hr drumplot display. 
This should sort out any time variations.
 
What's the affect of cooling on a magnet's flux strength -- or on the induced 

> voltage in a coil?

       Insignificant with your instrument.   

> Obviously, supplying a heat source might help. There must be a "cure", not 
> a patch.
>  
> (snip)
> "I can already see a "nighttime"  microseism problem, probably temperature 
> changes......which could be 
> a problem later in the fall and winter.  (Around 2-3 AM till after the  sun 
> is up and warms up a little, the trace gets stronger and noisy.  It clears up 
> and smoothes out later in the day.)"
> 
> (snip)
> "I experience this during the winter. My sensor in inside my home so I have 
> no problems during the summer. However, I typically turn the heating unit 
> down at night. This is when I get the problems. I placed a light bulb in the 
> closet that helps quite a bit. I usually only turn it on during the winter. 
> Several of us have experienced this problem. Maybe it's something we can work on 
> and figure out a solution."

       A known and well documented problem, for those who are not too lazy to 
read up the psn archives.
       Only you DON'T use a light bulb. This just attracts flying insects, 
spiders and creepy crawlies. You have enough problems without inviting 'bug 
quakes'. Bulbs also move the air due to convection. 

       With so many advisors, I wonder if some of the advice may be 
conflicting? You have not said what you have been advised and what steps you have 
taken. 

       Regards,

       Chris Chapman
In a message=20=
dated 04/07/06, gpayton880@....... writes:



Subj:Microseisms Discuss=
ion

From:    gpayton880@....... (Jerry Payton)

To:  chuckbou@............. (Boudreaux, Chuck), dwheelerf5@earthlin=
k.net (Don Wheller), tekmate@.............. (Joe Lincoln), jc3@................
(Cole, John), johnstilwell@............. (Stilwell, John), ChrisAtUpw@.......
m (Chapman Chris)




Hi Jerry,



       I suggest that you go to http://psn=
..quake.net/ and download the letter archives back to 1996. Decompress them i=
nto annual word processor files. You can then search for topics with 'find'.=
 Have a good long read!



       Amateur seismology is likely to be=20=
much more of a technical challenge than the professional variety. The profes=
sionals choose very low noise remote seismic sites, buy highly developed and=
 completely engineered seismometers at >>$5 K per channel and have the=
m professionally installed, often in boreholes to reduce surface noise.

  

    The amateur variety is very much DIY, with many en=
thusiasts constructing and then setting up their own equipment. Amateur site=
s are likely to be mediocre to appalling compared to the professional ones,=20=
so you have to learn to live with the limitations and to compensate for them=
.. When making and using your own equipment, you learn that success is hard w=
on and takes considerable time, effort and patience. You also learn how to s=
et up the level, the period and the damping, how to check the performance, i=
dentify and correct problems.



    The original Lehman was OK 'for a start' back in 1976=
, but the performance was limited by the poor point / knife edge lower suspe=
nsion amongst other factors. John Cole has pioneered the rolling contact typ=
e of suspension, which dramatically improves the performance and enables you=
 to set up stable periods of well over 30 sec.=20



    The considerable improvements in construction, suspen=
sions, damping and detectors that have appeared during the last 30 years do=20=
not yet seem to have been reflected in a 'good simple design' available to p=
otential constructors.=20



    Now Jerry, I know that you were experiencing setup pr=
oblems. What period are you using and is the damping set ~critical? Do you h=
ave a .psn file of the output?



    You can expect John's seismometer to be capable of a=20=
period of over 25 sec, even in a poor environment. You need to achieve this=20=
sort of period or greater to enable you to detect the long period Love waves=
.. If you aren't achieving this, you need to reduce the small angle between t=
he suspension axis and the vertical. It could be that the floor is not level=
, that you have not assembled it quite correctly, or that something has got=20=
bent / damaged in transit. If you are NOT getting a long period, THE ANGLE I=
S WRONG. The screw extension on the top wire has very little effect on the p=
eriod - it just enables you to get the mass at a suitable height above the f=
loor.





Hello Out There: PSN=20=
& ATN 

=20

I'm throwing this out for discussion and / or experimentation to the=20=
group(s) as a whole.  Anyone investigated this problem?  If it is=20=
temperature fluctuations, what is it affecting, the coil, the pendulum, or w=
hat?  The fact that the trace get amplified somewhat (in my case) indic=
ates to me that it may be affecting the electrical part: coil or magnets the=
mselves?  




       You have not really descr=
ibed your problems well enough for us to advise you.=20



       There is background environmental n=
oise which changes with time, the weather and a wide range of human activiti=
es. Microseismic ocean background is usually at about 6 sec and near sine wa=
ve, which again changes phase and amplitude with time. This exists at all ti=
mes. Wind noise can give a range of short to very long period signals. The s=
eismometer is very sensitive to changes in the tilt angle, from a variety of=
 sources - the walk up test. It is very sensitive to drafts and may also be=20=
noisy when the external temperature falls below the instrument temperature,=20=
due to convection. You need an insulating cover with all the joins 100% seal=
ed. If the joins are not airtight, it will likely be noisy.



       You may also experience electronic=20=
problems due to pickup from transients on the house power wiring. Fridges of=
ten give problems. Some areas have noisy supplies. Electric trains can cause=
 problems. Do you have the input line to the amplifier screened and the scre=
en and 0V line earthed? Some of the older / foreign computers had very inade=
quately filtered power supplies. Do you have a local radio transmitter, a TV=
 station or a phone transmitter aerial close by?  One test is to wedge=20=
the mass in position and take a trace.=20

  

       I suggest that you set the recordin=
g for a 24 hr drumplot display. This should sort out any time variations.

 

What's the affect of cooling on a magnet's flux strength -- or on the in=
duced 

voltage in a coil?



       Insignificant with your i=
nstrument.   



Obviously, supplying=20=
a heat source might help. There must be a "cure", not a patch.

=20

(snip)

"I can already see a "nighttime"  microseism problem, probably temp=
erature changes......which could be=20

a problem later in the fall and winter.  (Around 2-3 AM till after=20=
the  sun is up and warms up a little, the trace gets stronger an=
d noisy.  It clears up and smoothes out later in the day.)"



(snip)

"I experience this during the winter. My sensor in inside my home=
 so I have no problems during the summer. However, I typically turn the heat=
ing unit down at night. This is when I get the problems. I placed a light bu=
lb in the closet that helps quite a bit. I usually only turn it on during th=
e winter. Several of us have experienced this problem. Maybe it's something=20=
we can work on and figure out a solution."




       A known and well documented problem=
, for those who are not too lazy to read up the psn archives.

       Only you DON'T use a light bulb. Th=
is just attracts flying insects, spiders and creepy crawlies. You have enoug=
h problems without inviting 'bug quakes'. Bulbs also move the air due to con=
vection.=20



       With so many advisors, I wonder if=20=
some of the advice may be conflicting? You have not said what you have been=20=
advised and what steps you have taken.=20



       Regards,



       Chris Chapman