Going back to the late 80s, I've used two lengths of steel wire rope to connect
the 20' falling derrick to my homebrew 40' tilt-up/rotatable Field Day mast.
The mast supports a tribander and the top guys are inverted vees for 80 & 40.
It's light enough that a couple of burly dudes might be able to tilt it up/down
but I still use a winch. The cable is operated WAY below its rating. IME,
stretch is infinitessimal.
The mast uses common 1-1/4" Schedule 40 pipe, connected with modified rigid
electrical conduit couplings. 1-1/2" floor flanges serve as rotating guy rings
(they pass the pipe but not the couplings). Guys are at 20' and 35'. The base
is X-shaped, fabricated from angle stock, with a Tee fitting for the falling
derrick immediately above the bottom rotating joint. After tilting up, a short
piece of pipe + rod driven into the ground serves as a rotation limiter.
vy 73,
Bryan WA7PRC
> Date: Sat, 28 Jul 2012 22:31:20 -0700
> From: Rick Karlquist
> Subject: Re: [TowerTalk] IARU Team Stations
>
> Using steel helps, but the wire still forms a catenary
> that makes it behave as if it had some stretch.
>
> Rick N6RK
>
> On 7/28/2012 9:23 PM, Mark Pride wrote:
> > Rick,
> > The link from the top of the derrick to the tower
> (lifting component) is
> > a steel cable so practically no stretch here.
> > Regards,
> >
> > Mark, K1RX
> > *From:* Rick Karlquist
> > *Sent:* Saturday, July 28, 2012 11:18 PM
> > *Subject:* Re: [TowerTalk] IARU Team Stations
> >
> > This is obviously a successful set up, but one thing
> > that I don't like is that the derrick is rigidly
> coupled
> > to the tower. I tried this years ago and
> discovered that
> > if the rope between the tower and derrick has any
> stretch
> > in it, you can end up with a lot of strain on the
> > connection between the pieces. What I do instead
> is
> > have independent pivots for the tower and derrick.
> > Then the ropes are non critical.
> >
> > Rick N6RK
> >
> > On 7/28/2012 1:03 PM, Hector Garcia XE2K wrote:
> > > take a look
> > >
> > http://s1266.photobucket.com/albums/jj529/wrtc2014/WRTC%20Station%20Test%202012/K1RX%20Photos/
> > >
> > >
> > >
> > > also facebook
> > >
> > > http://www.facebook.com/wrtc2014
> > >
> > >
> > > J.Hector Garcia XE2K / AD6D
> > > Mexicali B.C DM22fp
> > > P.O.Box 73
> > > El Centro CA 92244-0073
> > > http://xe2k.net
> > >
> > > ________________________________
> > > From: Bud Kozloff
> > > To: towertalk@contesting.com
> > > Sent: Sat, July 28, 2012 12:52:36 PM
> > > Subject: [TowerTalk] IARU Team Stations
> > >
> > > Thinking of a "temporary" 35ft 25G Setup
> > > w/A4S on top similar to what
> > > they are doing for the 2014 temporary team
> > > stations.
> > > How are they installing the towers? Actually
> > > pouring foundations?
> > > Putting a 10ft section in a 5ft hole and
> > > digging it out afterwards?
> > > How are they installing the guys? Any
> > > info would be appreciated.
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