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[TowerTalk] AB chance screw anchors

To: <towertalk@contesting.com>
Subject: [TowerTalk] AB chance screw anchors
From: K7GCO@aol.com (K7GCO@aol.com)
Date: Mon, 5 Nov 2001 09:13:25 EST
 In a message dated 11/2/01 4:07:50 PM Pacific Standard Time, 
n2mg@contesting.com writes:<< 
  Not sure of the arrangement you are proposing...
  
  If you are attempting to co-locate two of these near 
  each other, and tie all the guys to the pair, I don't 
  think that you'd get much of an improvement. First, I 
  don't know how you'd effectively connect guys to two 
  anchors at once.  More importantly, if I understand 
  how they work, the screw anchors rely on a volume of 
  soil (I think approximating an inverted cone) above 
  the disk to hold them in the ground against the 
  pulling force of the guy wires. If you locate two 
  anchors near each other, IOW, so that these volumes 
  overlap, you would NOT get 2X holding power.
  
  You should get the expected improvement if you 
  separated the guys (assuming you have more than one 
  guy level) and put the top guy on one anchor, and the 
  lower levels on another anchor (that's located closer 
  to the tower).
  73 Mike N2MG
  
  > wa3gin@erols.com wrote: 
   > Wondering if I can use two per cable to increase the 
  > ratings?  My soil is sandy loam...  
  > thanks, dave wa3gin
    <<  >>
  Dave:  That is a "Great Idea."  Do that for the top guys--just to be sure 
for the time when there is "ice loading in high winds."  I had thought of 
adding a larger steel disk over the disk at the end of the anchor rod.  It 
does require a bigger hole just to get it in. k7gco >>
 
 It's assumed that the spacing between them is far enough so the inverted 
cones of dirt above the disks don't overlap.  I visualized one anchor behind 
the other about 10'.  Many many many years ago ARRL had in their Antenna 
Handbooks a simple technique I've used many times.  They showed a stake in 
the ground that a guy wire was attached to.  To enhance it's holding ability, 
another stake was driven in the ground about a foot behind with a connection 
between the top of the 1st stake to the bottom of the stake in the back 
sticking out of the ground.  This "double staking" really increases the load 
it can safely take.  I visualize the same proportional load increase 2 guy 
anchors one behind the other could handle which would be very useful in soft 
ground of any kind and insurance for that one extra load of the "big wind" in 
the summer and the "big wind in the winter with ice loading."  A frozen 
ground should give a more secure ground in the winter.  Cross bars can be 
driven in at an angle over the guy anchor to extend and beef up its inverted 
cone of conversed dirt above the disk at the bottom of the guy anchor. 
 
 A couple of years ago Spencer SD had the tornado that wiped out 1/3 of 
it--22 miles from my SD home.  The winds around it were strong also.  In the 
spring with normal rains the ground is soft and anchors can pull out with 
enough pull.
 
 There was an incident that "caught my full attention" while riding Amtrak 
back to Seattle one spring of heavier rains than normal.  There was water 
standing all over, basements leaking and farmers unable to get in their 
fields.  The train was slowing done frequently in particular around curves 
more than normal and other slow going more than normal.  The railroad bed is 
about 5' above ground level and fields were full of water.
 
 What really got me was there was a stretch of "Straight Track" about 3 miles 
long where we slowed down about to 30 MPH--while tilted at about 10-15 
degrees.  Since when are straight track runs tilted?  This is a piece of very 
bad track bed when "straight runs are tilted."  Guy wire anchors weren't too 
secure at this time and I heard of some pulling out.  
 
 I asked about this stretch of canted track and if they planed to get it 
leveled out? I was told "that they rent the track from the Freight Rail 
people".  I rode Amtrak in the winter one time in another route and they 
didn't hardly slow down at all in comparison.  The car is starting to look 
like a safer way to travel all the time.  K7GCO
 

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