[TowerTalk] Installing first tower

Scott Stembaugh radio.n9ljx at gmail.com
Tue Jul 31 21:08:59 EDT 2007


OK, I am finally preparing to install my first tower.  I have been reading
TowerTalk for quite some time hoping to gain some wisdom of some of the
experts.  I thought I should ask some direct questions to see if the answers
are what I think they are.  As you read thru these questions keep in mind
that money is a consideration.  I want to do it as best I can, but the
pockets are not deep.

The tower is an old 40' Rohn (so I was told) with a 16" face on the bottom
10'.  I have no idea of the model number and it is at least 20 years old.
In is in good shape structurally and has been painted annually by the
previous owner.  I do have the base section to bury in the concrete along
with the hinge.  The antenna is a KLM KT34A.  4 elements on a 16' boom. 6
sq. ft wind area, 45 lbs.  There will also be a 40/80 trap inverted vee
hanging from near the top.  This is the tower I have and it will be the one
I use.

This is in a suburban lot, 1/3 acre.  In order to keep all pieces parts in
my airspace the tower will be erected next to the house at the midpoint
lengthwise (ie, not near peak of roof).  I know that is not optimal but it
is what I have to work with. One end of the house is 7' feet from the poerty
line and the other is 10' or so but the peak is over the end of the concrete
driveway and I really don't want to bust that up.

Guying - What would you recommend for guying my tower?  I would like the
guys elevated and one of them "MAY" be attached to the house.  How far out
should they be from the base? I have little wind protection from the west
and northwest.  I was thinking 10' pipes with 3' in concrete and 7' above.
The tower will be house bracketed but only at about 7-10' high. What size of
guy wire should I use and at what height points should I consider guying
it.  If I do elevate the guys what size/type of support is best.

Grounding/lightening -  I have pretty rocky soil. Of course I am mainly
concerned about lightening protection.  I have a 6' ground rod i was
planning to use.  Is that sufficient or should I get an 8' or 10' rod(s)?
Do I bind the legs together with copper strapping or bring them seperately
to the rod(s)?  What is your recommendation for protecting the feed line and
rotor cable?

Raising and lowering - Of course i plan on using the hinge plate.  What
would be your suggestions for rigging a boat crank to raise and lower the
tower?  What about supporting it when it is down.  With the beam on it I
could only bring it down to the 8-10' level.  What supports would I need to
make sure the tower doesn't get out of kilter?

Planting the tower - How much gravel should I have in the bottom of the hole
for drainage?  And how big should the hole be, diameter wise?


What else should I be worrying about?  I am looking at 3-4 weeks to have
this up.

Thanks and vy 73,
--scott

-- 
------
N9LJX
radio.n9ljx at gmail.com
http://web.ics.purdue.edu/~scott/ <http://web.ics.purdue.edu/%7Escott/>


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