Take a look at the picture of the tool next to a pencil for size comparison:
http://www.k1ttt.net/images/2008_40m4lldd_repair_1.jpg
This tool was uniquely suited for one particular job while disassembling an
ice and wind damaged 40m4lldd yagi. Out of all the tools in all my various
tool boxes this one stood out for this one specific task.
Can you identify:
1. What it's original purpose(s) were?
2. What it would be used for in a 40m yagi disassembly?
Pictures of the 40m damage in progress are below... We had 3 ice storms in 2
weeks, 2 of them were followed immediately by strong winds. Besides damage
to both 40m4lldd's there were several bent elements on 20m4dx yagis that had
survived several years with 'normal' ice and wind. Something interesting to
note is that the loading rods on the 40m4lldd's did not provide any
mechanical strength to the elements even though they look like they would
act as trusses. The elements all bent on the same side of the antennas
because the wind hit them from the side while the element was already bent
down under the ice load. The same mechanism damaged all 4 elements of the
top fixed European 20m yagi that was sideways to the wind, while the
rotatable one above it only had 1 slightly bent element since it was
pointing into the NW wind at the time. The loading rods broke all on the
same side because the wind shifted while the elements were bent so one side
of the loading section was stretched against the side of the element.
Tower is 180' of Rohn-55 with the 40m4lldd's on ring rotors at 70' and 170'.
2/2 Top 40m with ice and wind
http://www.k1ttt.net/images/2008_feb_02_40m_ice_1.jpg
2/2 Top 40m with ice, note how on the left side all 4 elements are bent at
the sme place and the loading rods are below the element tubing.
http://www.k1ttt.net/images/2008_feb_02_40m_ice_2.jpg
2/2 Top 40m with ice element closeup
http://www.k1ttt.net/images/2008_feb_02_40m_ice_3.jpg
2/2 Bottom 40m with ice
http://www.k1ttt.net/images/2008_feb_02_40m_ice_5.jpg
2/7 Top 40m with ice and wind, round 2 of the storms you can see the 1st
loading rod broke on the right element. Eventually all 4 elements ended up
with 1 broken rod, all on the same side.
http://www.k1ttt.net/images/2008_feb_07_40m_ice_11.jpg
2/7 Top 40m with ice and wind, slightly crooked elements.
http://www.k1ttt.net/images/2008_feb_07_40m_ice_13.jpg
2/7 Top 40m broken loading rod closeup
http://www.k1ttt.net/images/2008_feb_07_40m_ice_8.jpg
Removal of the damaged antennas was done by XX-Towers on 3/7:
Rigging bottom 40m, tram line is cable coming down to left.
http://www.k1ttt.net/images/2008_mar_07_kc1xx_2.jpg
Bottom one coming down
http://www.k1ttt.net/images/2008_mar_07_kc1xx_4.jpg
Bottom one wide view
http://www.k1ttt.net/images/2008_mar_07_kc1xx_5.jpg
Closeup of broke loading rod end, its really not pulled out, the shorting
bar held and the rod broke. The ss saddle and eye arrangement on the philly
cable is my modification to prevent the philly from being cut on the side of
the small holes it used to go through on the shorting block. M2 has
modified the design with a strain relief to prevent that on new ones.
http://www.k1ttt.net/images/2008_mar_07_kc1xx_6.jpg
Rigging the top 40m, tram line is hard to see but comes down between guy
wires toward bottom.
http://www.k1ttt.net/images/2008_mar_07_kc1xx_7.jpg
Rigging top, wide view.
http://www.k1ttt.net/images/2008_mar_07_kc1xx_8.jpg
Liftoff of top one.
http://www.k1ttt.net/images/2008_mar_07_kc1xx_10.jpg
Top one starting down
http://www.k1ttt.net/images/2008_mar_07_kc1xx_12.jpg
Interesting rigging, use ring rotor supports and boom brace to spread load
to 4 points on boom.
http://www.k1ttt.net/images/2008_mar_07_kc1xx_13.jpg
Insurance has already paid off and I am awaiting delivery of a new 125mph
40m4lldd for the top. For the bottom one I salvaged parts from the top one
to make it whole and have purchased aluminum to beef it up similar to how
the 125mph elements are done. I also am waiting delivery of a 20m4dx to be
used for parts to replace bent element sections on those antennas.
Of course I am writing this today because we are now getting snow/freezing
rain/rain/whatever out there and I figured I can wait a while to continue
repairs.
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
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