point A sounds like you need to put a small heat source at the top, 
inside the box to stop convection currents starting when it gets cold in 
the evening.  I use 4 car tail light bulbs (ripped from a scrapped car) 
and I power them from a PC psu using the 5V supply.  The bulbs glow a 
dull orange but is enough to prevent the problem up here in snowy Scotland.

Hope that helps.

Cheers

Ian



On 14/11/2010 07:52, Bryan Goss wrote:
> I have built a new lehman seismometer and I have a few questions its 
> been several years since my last one and I have forgotten a lot.
>
> A. I have a small outdoor building not temperature controlled thats 
> why I built the wooden box with insulation.
> I am getting noise starting about 1:00am to about 9:00am
> should I build an outer box made of foam board and heat it with a 
> heating pad or something to control the temperature.
> link to the box and noise
> http://www.1goss.com/s-box.jpg
> noise example, I had it most of the afternoon although normally during 
> the day it looks like it should.
> http://www.1goss.com/noise.jpg
>
> B. The first sensor I built several years back I donated to the local 
> elementary school when were moving.
> It used the razor blade knife edge and steel all thread for the boom 
> and did not have the small aluminum rod I put in the new one.
> It worked well but I wanted to build a better one this time round so I 
> used a ball bearing for the pivot point, added
> the aluminum rod to help with vertical stabilization and used square 
> hollow tubing for the boom.
> Do you see anything wrong with this setup? I want //criticism / 
> suggestions if you have any.
> http://www.1goss.com/s-bearing.jpg
> http://www.1goss.com/s-top.jpg
> http://www.1goss.com/s-overall.jpg
> http://www.1goss.com/s-boom.jpg
> http://www.1goss.com/s-housing.jpg
>  I had a bit of trouble getting the 25sec period and am not sure it is 
> correct and haven't had a recordable local or teleseismic event to 
> compare with the local
> Helicorder Displays.
>
> C. Would a ball bearing at the top and all aluminum preform better 
> than a wire? and if  I use all wire what is the very best?
>
> Thanks for your time Bryan S Goss
>
>
>
>
>
>
>
>
>
>
>
>
>
>


  
    
  
  
    point A sounds like you need to put a small heat source at the top,
    inside the box to stop convection currents starting when it gets
    cold in the evening.  I use 4 car tail light bulbs (ripped from a
    scrapped car) and I power them from a PC psu using the 5V supply. 
    The bulbs glow a dull orange but is enough to prevent the problem up
    here in snowy Scotland.

    

    Hope that helps.

    

    Cheers

    

    Ian

    

    

    

    On 14/11/2010 07:52, Bryan Goss wrote:
    

      
      I have built a new lehman seismometer and I have a few questions
      its been several years since my last one and I have forgotten a
      lot.

      

      A. I have a small outdoor building not temperature controlled
      thats why I built the wooden box with insulation.

      I am getting noise starting about 1:00am to about 9:00am 

      should I build an outer box made of foam board and heat it with a
      heating pad or something to control the temperature.

      link to the box and noise

      http://www.1goss.com/s-box.jpg  

      noise example, I had it most of the afternoon although normally
      during the day it looks like it should.

      http://www.1goss.com/noise.jpg

      

      B. The first sensor I built several years back I donated to the
      local elementary school when were moving.

      It used the razor blade knife edge and steel all thread for the
      boom and did not have the small aluminum rod I put in the new one.

      It worked well but I wanted to build a better one this time round
      so I used a ball bearing for the pivot point, added 

      the aluminum rod to help with vertical stabilization and used
      square hollow tubing for the boom.

      Do you see anything wrong with this setup? I want criticism /
      suggestions if you have any.

      http://www.1goss.com/s-bearing.jpg

      http://www.1goss.com/s-top.jpg

      http://www.1goss.com/s-overall.jpg

      http://www.1goss.com/s-boom.jpg

      http://www.1goss.com/s-housing.jpg

       I had a bit of trouble getting the 25sec period and am not sure
      it is correct and haven't had a recordable local or teleseismic
      event to compare with the local 

      Helicorder Displays.

      

      C. Would a ball bearing at the top and all aluminum preform better
      than a wire? and if  I use all wire what is the very best?

      

      Thanks for your time Bryan S Goss