You better get some proper on-site help on this.
The sections can certainly be installed with a ginpole and maybe (or
probably) temporary guys, but 800 lb 20' sections require someone with
experience and the right equipment.
On 1/17/2012 6:07 PM, Doug Ronald wrote:
> I am in the process of constructing a commercial antenna for HF. The antenna
> itself is held in place by two 80' towers side-by-side with the antenna
> support going vertically between the two towers. The rotator is at ground
> level. These towers are designed to be guyed with four guys at the top of
> the 80 foot elevation. Since I am on my own putting this system together, I
> need to erect the towers in 20' sections. I have the two bottom 20' sections
> in, and I feel safe climbing up the middle of each tower. My reason for
> sending this info to this reflector is to try and get a seat-of-the-pants
> opinion on the safety of climbing the remainder of the towers as I continue
> adding the 20' sections to get the thing up without the guys installed.
> The manufacturer has off-the-record said if I must erect it piecemeal, only
> put in the lower 20' and then crane the remaining 60' in one operation where
> I would attach the guys with the crane still supporting the top sections.
> Getting a crane to the remote site where this antenna is located is
> problematic which is why I am doing it in sections. They officially sanction
> only using a 70 ton crane to erect both 80' towers fully constructed at
> ground level up to their final positions.
> I am not familiar with any other free-standing towers, so I have no
> structural reference to compare mine with; thus my invitation for opinions
> on this reflector. I have no structural design information on the towers,
> but they are triangular with 26" between the legs - no taper. Each 20'
> section weighs about 800 pounds (estimated). They are held in the concrete
> base with 1" bolts. Like I said, I'm comfortable with the stability of the
> first 20' section, but as I work up to the last section, I'm kind 'a
> concerned. Any thoughts? Am I worried about nothing here?
> -Doug Ronald
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