Hello everyone,

I am new to this hobby of seismology. After trying for years (I get sidetracked a lot) to make a 
seismometer (or is it seismograph???), I finally got it finished. I have made a Lehman 
horizontal seismometer. I am using WinSDR and WinQuake. I am using a Larry Cochrane 
16bit A/D converter and his amp/filter board. I have a GPS receiver (Mr. Cochrane's too) for 
timing.

I have photos of everything I will refer to at:

www.flickr.com/photos/darksky123/

I changed a few things. I thought it would be very difficult for me to made a perfect knife edge 
for the pivot point so I epoxyed a ball bearing to the end of my steel rod. I sanded smooth the 
surface that it rests on, (not sure what it is called). Seems to work???

For my pickup magnet, I hung it down off the rod. I could not get it to hang properly when I 
tried it on the side of the rod. Made things twist. 

I got a bolt for the thing that the wire attaches to on the top piece. To vary the period of the 
arm, I just adjusted the length of the bolt. 

So my question. I read that I should be able to detect magnitude 6 and greater for earthquake 
around the world. For a while after I got things running, there were no large quakes. The first 
large one was the 7.2 Baja Claifornia quake on Easter Sunday. I got a great record of it 
(I was pretty much bouncing off the walls when I saw it). I have a photo of the computer 
monitor and of the Winquake output. Since then I have not detected much of anything. What 
really prompted me to write was not detecting the Vanuatu 7.2 quake from last week. I got a 
small squiggle, but not enough to put WinSDR into alarm and the time was a couple of 
minutes early from when the waves should have arrived according to the USGS. Compared 
to what I got with the Baja quake, I thought I should have gotten something. I realize it is a lot 
further away, but I look at outputs that are posted on Infiltec's website of amateur recordings 
and some people get great recordings of a lot of earthquakes and I get nothing. I am hoping 
the people here that are much more knowledgeable than I am will be able to point out 
improvements or mistakes that I am making.

For my pick up coil, I originally had a coil from a relay. It was about an inch in diameter. It 
seemed to work for starting out. That was the pickup coil I was using when I got the Baja 
quake. I knew I had to get one with more turns of wire and a higher resistance, that one was 
only about 300 ohms. A local electronics shop had some 40AWG magnet wire, a 1/4 pound 
roll. I bought it and made a thing to roll it onto. I got about 1/3 of the way through and there 
was a break in the wire on the spool! I tried to join it together as best as I could, but 40 AWG 
wire is pretty small and hard to work with. It worked for a bit, but as I worked on a mount for 
the spool, the coil opened up. Not really feeling like playing with that tiny wire again, I looked 
through an electronics supply catalogue and found a 110Vac power relay that stated a coil 
resistance of 11K ohms. I bought it and in fact it has about 10.8 K ohms. I took the relay 
apart and got just the coil. The question I have about it is, does size matter? The coil itself is 
only about 1/2' in diameter. I look at other amatuer seismometers that I can find photos for 
and the coils are a lot larger. Should I get some larger gauge wire (36AWG?) and make a 
new coil? Or is the coil I have now OK? I only have it secured to a small piece of scrap 2x4 
now. If the coil is Ok I will build a better mount for it. 

I believe the seismometer works. When I walk up to it, WinSDR shows movement and it 
usually goes into alarm unless I walk up very slowly. I have a road construction site very 
close to my house. The trace is very noisey during the day when the construction is going on. 
But in the eveings and at night, (See one of my photos you can see the trace go quiet at 7:00 
p.m. when the construction shuts down for the night), the line gets a lot smaller. I can also tell 
when it is windy outside, by the output of my seiesmometer. I can also see a larger trace with 
the new coil inplace. So I think that the new coil did make an improvement in my system. 

The period of my system is about ten seconds. That is about as long as I am able to get it. I 
can't seem to get the 14+ I read about for some systems. Should I fight with it to get a longer 
period, or is ten seconds long enough?

Is a ball bearing Ok for a pivot point?

I sent a letter and photos to Mr. Cochrane and he told me to get rid of the wood I was using 
on my system. I had made a mount for the pick up coil magnet out of wood at first (it is now 
metal). It is easier for me to work with wood than metal. I have the copper plate for my 
dampening attached to the rod with a piece of wood. Is this OK? The original diagram I was 
working with says use wood. Should I get rid of it too and use metal?

I have my seismometer orientated basically north-south. Is that Ok for North America or 
shoud I point it east-west?

Should I be getting more earthquakes. Or for where I live, are things working as best as I can 
expect?

I hope someone out there will be able to help me out and answer my questions. I have found 
in the past that if you are having a problem with a project, most likely someone out there had 
the same problem. Get with a group of people that have the same interests and you most 
likely will be able to get an answer. I am hoping that this will be the case.

I am looking forward to my new hobby of seismology. If things work well I hope to make 
another one for the other direction and maybe even a verticle seismometer. I bought a three 
channel amp from Mr. Cochrane. Just in case... :-)

Thanks for all your time. Kind of a long letter...

Jeff Zambory
Calgary, Alberta
jzambory@.........






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