Rohn 25G with Ham-IV rotator

[K7LXC@aol.com]

In a message dated 96-08-02 23:50:25 EDT, you write:
>I am getting ready to install a Ham-4 rotator in a Rohn 25AG3 top section.
>The 25AG3 doesn't have enough room in the "open" area at the top of the
>section to accomodate the height of the rotator.  The rotator is too big to
>push down further into the tower and will not rotate inside the tower except
>where the tower sections join together.

Hi,  Dennis --

    I'm slightly confused by your remark about the Rohn section "not having
enough room" for mounting the rotator.  The AS25G accessory shelf/rotator
plate is adjustable as far as mounting and can be mounted in just about any
place in that section or any   section.  Is your section so short that this
is not possible?  If so, just go down the tower until you reach a convenient
spot for accessory shelf attachment.  What do you mean that the rotator is
"too big to push down the tower"?  Do you mean mounted on the accessory shelf
or what?  If you have it mounted directly below the tubes at the top of the
section, you're right but the rotator should be mounted below this point
where it CAN be installed with plenty of clearance.

 >It looks like the best place for it is at the top of the "next to top"
>section. The rotator should rotate freely there, but how do I get it in or
>out without lifting the top section and the antenna?  

  The rotator WILL fit into a 25G section without cutting anything.  With the
right combination of pushing, pulling, shoving and American slang, it WILL
pop in.  
>
>I like the idea of having the rotator 9 ft or so down in the tower.  It
>seems that the laws of physics make this spot better than right at the top
>for several reasons, but if not, I would like for someone to set me
>straight. .

    Actually, mounting the rotator farther down the tower is a good deal;
mounting it at the bottom of the tower is even better.  The reason is that
the mast acts like a spring (a big torsion bar) and absorbs much of the
twisting force before it reaches the rotator.  The practical problem is the
length of the mast and coupling it plus the additional cost.   >
>I am considering cutting out the bottom horizontal brace on one side of the
>top section, then replacing it with a piece of pipe or angle stock with 2
>U-bolts. This "temporary" brace could be swung out of the way to install or
>remove the rotor.  
>
       You don't need to cut anything; see remarks above.

73 and good luck,  Steve   K7LXC

    TOWER TECH -- professional tower supplies and services for amateurs