[TowerTalk] Tiller Details for Tramming Antennas

[Kurt Andress]

Selbrede, Bob W. wrote:Snip

> I've seen
> some references to a "tiller" attached to the antenna boom and the tram line
> to keep the attitude of the antenna correctly aligned on the trip up.  It
> seems as though a tiller device might be just what I need to keep this thing
> under control without the need for a bunch of tag lines and the people to
> man them.
>
> Has anyone taken the time to draw a sketch of the proper rigging arrangement
> necessary to do this?  If not, I'll do so after I've gotten a better handle
> on the utility of the "tram/tiller technique" for putting up large Yagis.
> I've seen numerous references to antenna tramming on the reflector over the
> last few years but I haven't found a good description of the complete
> process yet.  Any suggestions would be appreciated.  Ideally, since I don't
> have a lot of local hams to help out, I would like to turn this into a 2
> person project.  I'll post a summary later.  Thanks!
>

Hi Bob,Funny to see that we're using a yachting term this time to describe
something for antennas. But, it is a good use of the term.
Here's what I use, and many others I know.

Make a 2-3' piece of angle or channel. Drill two holes along the axis of one
face of the angle, or channel, at one end to accept a muffler clamp that fits
the center section of the boom. The other end gets one hole to accept the pin of
a shackle.
Attach the tiller to the boom as close as possible to the center, this is
usually right up against the boom - mast plate.  Attach the pull-up line to the
shackle end.

As the the antenna goes up the tram, the load on the pull-up line keeps the boom
perpendicular to the tram line (more or less). It works like a torque bar on a
tower.
The antenna will not stay perfectly aligned, but the gadget will definitely keep
it from going out of control too far. The longer the tiller the more effective
it is.
You can still put tag lines on the boom ends. Specially, if you need do do some
other antics when you get it up there.

The main complication with a tiller is that when the antenna gets near the
tower, the upper end of the tiller bottoms out in the sheave that the pull-up
line runs thru, before the mast plate is against the mast.

The most common solution is a separate lift line thru a sheave mounted above the
antenna mounting location. When the antenna gets to the top, transfer control to
the lift line and remove the tram pullup line and tram line sheave (if
necessary). Then the antenna will swing into the mast. I always leave the tiller
on the boom until it is in place. It is a great antenna control device.

We put up a 39' 40 meter antenna yesterday using a tiller. It worked just fine.
The available area around the tower didn't allow for real tight tram line, so we
had to finish the install with the lift line.
I'm sure the rest of the tram biz must have been beaten to death in the past. If
you have any other questions let me know.

73, Kurt

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