Anatomy of a Broadband Seismic Station

Fencing the Site

If there are enough people on the site construction crew, site fencing can occur concurrently with digging and installing the sensor vault.  The need for fencing depends on the site location; our project was located in cattle country and nearly every site required a fence.  Our fences are approximately rectangular, with 3 strands of barbed wire.  We used the following procedure:

• Select the location of the 4 fence corners, and install 6-ft long metal "T" fence posts. 
• It will help with space efficiency if the fence is oriented east-west and north-south, because the solar panels must face south if the site is in the northern hemisphere. 
  
• At each corner, install an inward-angled brace post.  The fence will be stronger if all brace posts are placed so that they meet the corner posts on the same side, as viewed from the center of the site.  Use heavy-gage soft iron wire in a double figure-8 wrap to connect the corner posts to the braces; the wire can be tightened with locking pliers.
• Working from the bottom up, install each strand of barbed wire.  Begin by tying the wire off to a corner post, then unroll the wire (a shovel handle through the center of the wire roll helps here) while walking carefully around the outside of the site.  Finish back at the corner where you started.
• When installing barbed wire, it is best if the tension of wire installation pulls the corner posts into the brace posts, instead of pulling them apart.  This is why all braces are placed on the same side of the corner posts.
• Working around the site in the same direction the wire was rolled out, have one person pull on the wire to make it tight, while another installs fence clips on the corner posts.  Continue around the site, and tie off the wire to the starting post.
• Repeat until all 3 strands of barbed wire have been installed.
• If the fence is not sufficiently tight, it may be necessary to install intermediate posts.  Choose the loosest or longest side of the fence, and install a post which pulls out that side to tighten the fence.  This, too requires at least two people; one to drive in the intermediate post while another holds the post and keeps the barbed wire pulled back out of the way.
• Finish any intermediate posts by installing fence clips.

Leave behind 2 fence posts for future installation of the solar panels, and you are done with site construction.  Return later for Installation...