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Re: [TowerTalk] new tower for W0RTT

To: <>, "Grillo's" <>
Subject: Re: [TowerTalk] new tower for W0RTT
From: "Tower (K8RI)" <>
Date: Sat, 14 Feb 2004 20:40:59 -0500
List-post: <>
I added a third guy on the 97 foot (they'd call it a 100') tower.

> I just got word back that Rohn is changing hands and their current
> schedule is worrysome.  Can someone help me find a suitable tower?  I was
> planning on Rohn 45, 90' on a 5' base buried in concrete.  Top of tower
will be
> SteppIR 4-el (9.5 cu ft wind load) and 2 element 40 about 6-8 feet above
> selected yet).  I would estimate total wind load will be around 20 sq ft.
> >From the Rohn website, 90' of 45G has only two sets of guys and is only
rated >for 8.8 sf of flat antenna load one foot off the top.  You'd be
overloading >this unless you have an SE do some calcs.

I can't find my paperwork but adding the third guy raised the windload
I have a TH-5 one foot above the top, a 7L C3i 6 meter yagi at 115 feet and
a small 2 meter and 440 array at 130.  The mast extends nearly 20 feet into
the towerand is supporte at three points.  Two thrust bearings with one at
the top of the tower, one half way between the top and rotor as well as the
rotor itself at the bottom..  It has withstood over 70 MPH gusts on two
occasions.  I've been up there when the wind was above 25 MPH and the top
doesn't move.  No, I've never even had the desire to see if it moves or not
above that, let alone 70 MPH.  <:-))

The only thing I'd change is the mast. Although half is 1/4 inch wall with
the center half being 1/2 inch wall, it is far too springy.  When the winds
get above 60, that mast with the 144 and 440 arrays looks like a Bluegull
fly rod that just tied into a monster Bass.  The 6 meter antenna moves
around a bit, but not bad.  (It's right at the top of the 1/2 inch wall
mast) OTOH I'm amazed that the 144 and 440 arrays are still intact.

> I have selected the heavy duty Yaesu rotator for this using a 12' steel
> >Heavy duty mast correct?  And, I'd talk you out of the Yaesu and go with
a worm >gear AlfaSpid from Alfa Radio.  Better torque, no brakes, electronic
control >with digital readout, computer controllable and presets.  Very
I'd agree.  There are several rotors on the market like this and although
not cheap they are worth the money.  I have a brand new Wilson which I think
is the same as the Yaesu.  I didn't have to think long about not using it.
It's a monster, but the gears are fragile.

> On the side of the tower will be another StepIR 4-el about 33' down the
tower, just above the 2nd set of guy wires.  I was planning on using
Philistran for the top set of guys and steel for the lower two guys.  Texas
Towers has been very

I used Phillistrand for all three sets.  6600# test for the top and 4400#
test for the middle and bottom sets.  If you have the chance to work with
the Phillistrand and ROHN EHS steel, I think you will see why I chose to go
with all Phillistrand.

Properly tensioned the catenary is barely visible using either the 6600#
test, or 4400# test Phillistrand where the EHS steel has a very pronounced
catenary.  I can carry 300 feet of 6600# test Phillistrand on one arm.  It
takes both to just lift a coill of 1/4" EHS.

> helpful to me in selecting these items and has most of them in stock,
except for
> the tower.  Does anyone on this reflector have any ideas where I might
find the
> tower and related parts?.
Hope you can find everything without having to wait for them to be

Roger Halstead (K8RI, EN73 & ARRL Life Member)
N833R, World's Oldest Debonair (S# CD-2)
> >Try Hill Radio in Illinois or AN Wireless who supplies Rohn equivalents.
Also >the AN Wireless self supporter would work for your loads.  Just my two
> I have already sourced the steppIR antennas.
> >These are very nice.  Gd luck, cu in the pileups, Phil  KB9CRY
> _______________________________________________
> See:  for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
> _______________________________________________
> TowerTalk mailing list


See:  for "Self Supporting Towers", "Wireless Weather 
Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions 
and ask for Sherman, W2FLA.

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