Having no idea of the location, don't be surprised at all if having the
commercial users on the tower turns your permit process into a major
project.
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
On 7/18/19 7:06 PM, Matthew Kaufman wrote:
Thanks! This is useful for ballpark costing. Plus who knows what it'll cost
to permit, given its legacy status with the county.
Matthew Kaufman
On Thu, Jul 18, 2019 at 4:48 PM Charles Morrison <junkcmp@gmail.com> wrote:
Having done a 120ft 140 MPH tower last year I grabbed my costs and applied
them to your plan:
NEW PARTS 170ft 130MPH 55G 4-guy levels no insulators
$2500 for new Rohn anchor rods GAC5755TOP $825 ea +ship
$400 rebar -pickup
$200 lumber -pickup
$6000 17 new 55G sections +ship (Find used and save 50%, but
life is reduced.)
$1500 All other Rohn parts BPC55G APL55G (4) GA55GD +ship
$ 315 700 ft 5/16" EHS $0.45/ft +ship
$ 475 1575 ft 1/4" EHS $0.30/ft +ship
$ 48 6 5/16" Guy grips / Big Grips $8 ea +ship
$ 108 18 1/4" Guy grips / Big Grips $6 ea +ship
$ ~500 Thimbles, Shackles, End sleeves/ice clips. +ship
$ 200 Bolt cutters pickup
$ 425 12 3/4TBE&J Galvanized Turnbuckles $35 ea +ship
$ 100 Safety Wire & parts +ship
$ ??? Grounding +ship
You build guywires 2-3 days 1 man.
Tower crew: Remove ants & cables
Tower crew: Demo tower ( release 1 guy) cut up for scrap, (You could
do all of this & haul away)
$500-1000 One day anchor hole prep $500-1000 Rohn AB3
Build rebar cages 1 man 2-3 days
$ ??? 6-to-8 yds 4000 psi concrete +ship
Tower crew: Erect tower
Tower crew: Install new feedlines and old antennas
=============
Totals:
New Parts discounted retail $13000 + Tower crew ($5000-$10000) + new
feedlines and associate parts + backhoe + shipping + concrete
+ your free labor listed above.
Guess: $25000 to $35000
-Charlie N1RR
On Thu, Jul 18, 2019 at 7:01 PM Matthew Kaufman <matthew@matthew.at>
wrote:
Hoping to gather some community wisdom before embarking on a tower
replacement.
I have a 2.5 acre property on a slope with what I believe to be a Rohn 55
tower that was installed as a commercial paging transmitter tower in 1971
at 150 feet, then extended sometime in the 1980s to 170 feet when they
switched from VHF to UHF and then 900 MHz paging. (The top (5th) guy level
was quite clearly added using an existing hole on the anchor and a
strandvise instead of the big grips that were used for the other guys.)
The tower has withstood at least one lightning strike, the 1989 Loma
Prieta
earthquake, and numerous storms,... but the guys are getting very rusted,
the tower is rusting (despite a coating of zinc-rich paint a couple years
ago), and the guy anchors are in unknown condition (though visually "ok").
I'm not sure how long a tower should last, but it can't possibly be
"forever".
Two of the guy anchor locations are just above the tower elevation, the
third is some tens of feet lower. Each guy anchor has a metal rod that
extends 3+ feet unprotected through dirt and then into a concrete block .
The tower has a pier pin base on concrete which is below ground level, so
is in a bit of a well with retaining blocks around it (had been buried
under the earth when I acquired the property and tower).
I have the following limitations:
1. I want to have minimal downtime - the tower has a couple of
heavily-used
ham repeaters, a commercial repeater, and a wireless ISP on it.
2. The county would never issue a permit for a tower like this today...
the
property has a use permit for the tower, specified as "18 inch face" and a
drawing of its approximate location on the property. So I need to somehow
permit this work as "replacement in kind". A new tower would be limited to
53 feet in this zoning district, with a possible variance available to 78
feet... the trees are taller than that.
3. I have no construction drawings for the guy anchors or the tower base,
and have no way of nondestructively testing the strength of the guy anchor
rods.
4. I'd like to ensure that the tower can support the existing and future
microwave dish loads, and reduce the twist both for those and the fire
detection cameras I have up top... so maybe should go to star guying?
So... I need to choose a tower that is roughly 18" face width (possibly
just Rohn 55 again), and install it at (if I trust the foundation) or near
the existing tower location, with presumably new guy anchors that must be
near but not at the existing anchor locations (to minimize downtime), and
do as much of the removal and installation as possible with a crane (or
helicopter?). I also need to not break the bank, as this is really a hobby
tower for me, where the commercial customers are mostly to pay the
utilities and property taxes.
Thoughts? Alternatives?
Matthew Kaufman, KA6SQG
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