[TowerTalk] tower replacement wisdom

[Jeff Blaine]

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 at 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 at 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
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>