Scott--
Sounds like you are getting lots of good advice.
I had a stack of two of the 4L40M KLMs stacked with
four TH7s. Two of the TH7s were within 5 ft of
their respective KLMs. Never had the tribanders
affect the KLMs in any way. Although the KLMs did
bother 15M on the tribanders.
I think the most likely scenario is something shorted
in the feed system. The crossed-over phasing lines
are the most vulnerable. When the boom is bowed up
slightly by the top guy the phasing lines can short to
each other or to the boom.
I ended up using some light dielectric rope to help
support the phasing lines above the boom. If you
pull the driven elements far enough apart to put
significant tension on the phasing lines to keep them
apart you are likely to pull out the ends of the phasing
lines when the boom bounces in the wind. The
phasing lines can just fail at the connection holes.
Best to keep them somewhat loose and support
them with their own little top rope.
Of course my stack of 4L40M antennas was
mounted on the face of Rohn 55 using 10" aluminum
channel and the channel added some unique problems
in clearing the mount with the phasing lines.
Good luck--and if you have a digital copy of my
4L40M notes you might send them to me--I seem to
have lost them in the move to TX. They are probably
on some computer--but I have about 20 here and
some are in storage. And since you mentioned my
call, someone is bound to write! ;-) And I can
probably add some more details now.
BTW I have FOUR of them now. Two in boxes and
two still up in CO. Both in CO have finally shown
a failure--and the same failure. A tip on one half-element
has pulled out. But the tip is still being held in the
air by the linear loading. I suggest pinning the
elements if you don't want this to happen. But I got
about 10 years out of them without ANY of the
well known failure modes by using my minor mods.
Think the mods must work! Still need to take the
two down in CO--or talk Duffy out of his! You can
bet I will pin the element sections in the future.
73 es gl John W0UN
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