[CQ-Contest] Adjusting Phillystran Truss so boom is level for DB36 Steppir

FritzOAQ fritz at k4oaq.com
Sat Feb 9 18:05:00 EST 2019

The following was done for each side of the truss.

With the boom horizontal on saw horses and the turnbuckle unwound so that
approximately 3/8" of threads are still inside the frame, I tightened the
wire clips while holding the phillystran so it remained tight. (This is my
understanding of what the instruction manual says to do.)

I then secured a pipe to the mast plate so I could see how level the boom
would be when up on the tower.

With some effort, my XYL and I balanced the monster to get a reading with
the level. Ugh, the boom was not even close to horizontal with the
turnbuckles as tight as they would go.

I called a friend who told me it should be level, i.e., horizontal with no
sag. If it had been close, I would have ignored this sage advice but it
wasn't even close.

Note that each truss is secured by 4 wire clips that are a pain to tighten.
So, the monster goes back onto the saw horses with the ends raised up a ways
so there's plenty of slack in the phillystran trusses. I figure (incorrectly
in hindsight) that tightening up an additional 3 inches on both sides would
be plenty sufficient to do the trick. So, if you haven't guessed, the sag
looks a lot like it did before. I.e., NOT horizontal. I honestly don't know
what the exact sag is because this time I was by myself and didn't actually
have the boom supported by the mast. I did raise the mast plate enough to
determine the boom was not close to horizontal though.

So my question is how horizontal does the boom have to be? And if the answer
is that it doesn't have to be exactly horizontal, then I'm looking for an
answer like "6 inches from horizontal over a 3 foot length of the boom" or
something like that. If I get different answers, I'm thinking I may average

Also, is there a relatively easy way to hold the mast securely. I can only
think of pouring concrete or using guy wires. BTW, "XYL" is not a good

Thanks for your time guys.


Fritz K4OAQ


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