[TowerTalk] TA32M & Spiderbeam Push Up Mast

[EZ Rhino]

Hi Frank,

It seems like a feasible plan.  I have a little bit of experience with the SpiderMast, so I can offer some insights.

It is a well built unit, and quite solid when raised.  Its big advantage is the portability.  It fits inside an 8" square box about 4' long.  It's big downfall is the major PITA to get an antenna raised on it.  (It's also not particularly cheap).

I have set up a 5 band SpiderBeam on a 50' Spidermast at Field Day and 7QP.  The reason it is hard to erect is the increasing weight when pushing each section of mast up.  At first it isn't that bad, but it becomes increasingly heavier the taller it gets.  It becomes impossible (unless you are Mr. T or Arnold the Governator) to hold with one hand while tightening the clamps with the other to keep the section just raised in place.  It really requires two people.  Also, the mast when fully collapsed is 5-ish to 6 feet tall, which means you need to stand on a ladder placed right next to it in order to be tall enough to raise each section.  This puts you at an awkward angle leaning over to muscle each section up.  Another difficulty is when you push up a section, the entire mast wants to raise (or come off the ground) because of the close tolerances (friction) from tube to tube.  Finally, the three guys need to be continually slackened as the mast goes taller.  This is really tricky if it is windy.

My buddy devised a clever system of using a farm jack (hi lift jack) to jack up each section, making the raising somewhat easier, but creates a new set of problems that I won't go into here.  So it takes a minimum of 45 minutes to get it airborn, and then you run an SWR check and realize the antenna needs tuning and then you let it down and start all over. hihi.  One advantage is you can get it completely down in a couple minutes.

We threw in the towel after 7QP this year and pulled the trigger on a Universal aluminum tower, 4 sections, 40' tall.  With a mast it will be between 45-50 ft.  Each tower section is tapered and nests inside the largest section, making transporting it fairly easy in a pickup truck.  (4 sections weigh 85 pounds).  Currently I'm getting it ready for Field Day.  I'm building a hinged base out of 2x6's and it will be guyed (obviously) at the top.  The mast will have a hinge on the top which will allow the antenna placed on it horizontal to the ground when the tower is laying flat, then can be brought to horizontal when the tower is stood up.  We're going to use a modified falling derrick method of raising it.

Chris
KF7P






On May 28, 2010, at 12:57 , <w1nk at cox.net> wrote:

Can anyone find anything wrong with my plans?

I would love to put up my (stored) TA32M but would prefer avoiding the expense, etc of a tower.  I happen to be looking over the Spiderbeam website and came across their aluminum push up mast ("heavy duty").  The mast is 7 sections ranging from  2.75" at the bottom to 1.5" at the top.  Wall thickness is 2mm.

According to the manufacturer this mast will support the heavy duty Spiderbeam which has the following specs:
Boom: 33 ft
Turning Radius: 16 ft
Wind Load: 3.8 sq-ft
Weight: 23lbs.

According to the Mosley website, the TA32's specs are nearly identical.

The setup would be guyed (obviously) using 2 ft ground stakes (Spiderbeam's) or 4 ft ground screws (DxEngineering).  The rotor would be a base mounted HD73 (also in storage and refurbished about 15 years ago).

So, tell me my thinking is too good to be true.  Or for that matter if I have a workable setup.

Frank, W1NK
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