US Crank up Tower install question!


Mark Low:
Hello, I have just completed the final stages of my TRX-472 installation. I am using the raising fixture for bringing the tower up to vertical position. I have a 20 foot HD mast and a two element Cubex Cuad on the very top.

My qustion is about installing the rotator. I wonder if I should go ahead and raise the tower to vertical position, and crank it up just until the rotor plate is cleared and then should I climb up to the top and try to push the mast all the way up through the top until the bottom is in place for installing to the rotor? If this is the way to do it, I am afraid that I will not be able to raist the mast by hand since it is quite heavy with the beam and all.  Now in reviewing US towers installation notes, it appears to be suggesting that I lay the tower over at some angle 30 or 40 degres and sucure it their in that position. Then crank up the tower just to the point where the rotor shelf clears and then use a step ladder or something to place the rotor, but first I must push the mast up to that position. I am just afraid that it will be to much strain on the mast section when 16 feet of it is comming out of the top while it is laying over in that position. Is this the way it is supposed to be done or is it the other way I mentioned, climbing and pushing the mast up from there?


Pete Allen:
Mark, I installed the rotor, rotor shelf, thrust bearing and mast with the tower on the ground, raised my HDX55 enough to install the 4L quad, let it down on solid blocking while I put the quad and transmission lines on, and then finished raising the tower.

I would not under any circumstances suggest working on any tower in a either partially raised or partially extended position. Life is short enough, and I want to live a long time in full possession of my fingers and toes!

And one more suggestion - it's a darn good idea to get one of Amidon's or Bytemark's largest 243 mix ferrite toroids and run your rotor cable through as many times as you can as close as you can to the rotor itself. This simple procedure helps keep RF from burning pits in the direction potentiometer, necessitating a teardown to fix the rotor.

73  Pete Allen  AC5E

Thomas Hamilton:
I installed a 10/15 interlaced yagi above a 5 element 20meter on my 72 foot crank up. I installed the 15 foot mast and rotor first, then with the beast still cranked over, installed one side of the boom for each antenna with all the elements, cranking up slowly until finished, and then cranked all the way upright, rotated 180 degrees, cranked it back over, and assembled the other half of the boom and elements in likewise manner. This was all done standing on the ground. I did not have to use a ladder. The reinforced mast had no trouble holding all 140 pounds of antennas in the horizontal position.

It took a lot of planning and a couple days to accomplish but it all went together.

I would think that your 2 element quad would be an easier task utilizing my method.

I would not recommend climbing an extended tower. It is a guillotine waiting to happen.

Good luck, KA4P

Mark Low:
Thanks... That sounds like that is what I will do. However, since I have already installed the antenna and switch box with feedlines with the mast only partially extended and the rotor not installed, I probably shoud be able to just go ahead and lean the tower over as far as possible without letting the antenna touch, and try to pry the mast from the bottom up until it is fully extended. Then I can install the rotor and go back up with it.

Since the antenna will be placing downward force on the mast while leaning over, I might need to have someone support the weight to reduce friction and allow the mast to slide up through the top more easily.

I figured there should be no reason to climb a crank up tower, even in its fully nested position, but I did notice that US Tower does make a service platform to go at the top of the base section, about 24' from the ground. They also make a mast raising fixture which is just a simple hand winch and cable assembly. I thought it might be wise to later purchase those if I plan on changing things around up there.

The problem I may face is that of having not enough space to have the tower leaned over with the 20' mast and rotor in lace. That is partly why I went aahead and installed the anttena with the mast only extending out about 8'. I will need to clear a fencewhich is 40' from the tower base in the direction which the tower lays down., and the vertical elements on the Quad really make it kind of difficult.

I will bring it down again and re think it and hopefully can get it back up and completed soon. I have raised amd lowered the thing now 5 times in the last 3 days and it gets to be pretty difficult.

Thanks, Mark, N5LPT

Steve Katz:
All kinds of things you can do, and the work platform helps a lot.

What I usually do with a heavy mast/antenna combination if I have to do the work *myself* (no helpers) is to make sure the thrust bearing is tightened so nothing can slip as the tower tilts up.  Then, tie one end of a pull rope to a car bumper jack and, with all tools in my belt pouch, climb the tower.  Once I'm securely buckled up at the top of the tower (with the tower sections all nested, of course!), I pull up the car jack and position it to assist me in jacking up the mast.

I try to position myself so that I'm about eye-level with the top plate of the tower (above the rotor plate, and convenient for reaching the thrust bearing) and comfortable; then, once the jack is in place, loosen the thrust bearing, jack up the mast several inches (as high as it will jack before the jack runs out of room or something starts hitting the tower webbing), tighten the thrust bearing, move the jack higher, and go through the same exercise again.

After a few times of doing this, the mast's up as high as you want it, and the only exercise you got was climbing the first 20' of the tower and moving the jack handle up and down.

Then, I'll lower the jack using the lift rope, climb down the tower, tie on the rotor and cable end (if the rotor cable's not already strung up the tower), climb the tower, and pull up the rotor for installation.

Even with a 200-pound mast/antenna combination, I can maneuver this stuff alone provided I take my time and use the jack.  (Up to about 100 lbs, I wouldn't bother with the jack, I just try to rely on brute force and hope I don't get too tired...but if you rely on the thrust bearing to hold the mast so if you let go, it cannot slip more than a few inches, it's pretty safe.)

If you haven't done this before, remember the rotor cable has to take the same route as your coaxial cables, *outside* (not inside) the tower, preferably supported by the standoff arms.  The only place the rotor cable runs inside the tower at all is right below the rotor, where it should run up inside the smallest tower section (tied to the inside of one of the tower legs) until the very top of that section, where the cable can wrap around the leg and exit for routing back down the outside of the tower, along with your coax.  This will prevent the rotor cable from getting "pinched" as the tower retracts, when you exercise the tower.

I only mention this last item because so many hams who haven't done this before end up doing it wrong, and then waste a lot more time figuring out what to do up there....




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