Hi,

I have a 4 el., 5 band quad on a Yeasu rotator on a Heights Aluminum tower.
The antenna is swinging, in a fairly stiff breeze today, a total of about 20
degrees of arc. Of course that's not a problem with the width of the beam of a
4 el quad, but the 24 el 2 meter antenna I plan to add might have an issue with
that much swing. I forget which model Yeasu rotator it is, but it is supposed
to be big enough for the 4 el. quad (30 ft boom). G450? I think?

Anyway, is 20 degrees in a stiff wind too much? Can I expect the rotator to
fail soon over this? The tower does not appear to be twisting. The rotor base
plate doesn't seem to be moving. I don't think there's that much play in the
bolts of the masting, and the tower appears tight to the mast. I think the
play is in the rotator.

Is it common for a rotator to have that much play?

Dave Head

I have been looking at my beam also thinking it is moving too much in
the wind. It is a Yaesu rotor and a Moseley 4 element beam. Almost looks
like the 2" mast (about 5 ft.) is flexing, but I am pretty sure that
can't be. It is up 45 feet on a Universal Aluminum unguyed tower very
firmly mounted in concrete.

Dave Head wrote:
Hi,

I have a 4 el., 5 band quad on a Yeasu rotator on a Heights Aluminum tower.
The antenna is swinging, in a fairly stiff breeze today, a total of about 20
degrees of arc. Of course that's not a problem with the width of the beam of a
4 el quad, but the 24 el 2 meter antenna I plan to add might have an issue with
that much swing. I forget which model Yeasu rotator it is, but it is supposed
to be big enough for the 4 el. quad (30 ft boom). G450? I think?

Anyway, is 20 degrees in a stiff wind too much? Can I expect the rotator to
fail soon over this? The tower does not appear to be twisting. The rotor base
plate doesn't seem to be moving. I don't think there's that much play in the
bolts of the masting, and the tower appears tight to the mast. I think the
play is in the rotator.

Is it common for a rotator to have that much play?

Dave Head

Maybe its a Yeasu characteristic, but I doubt it. My biggest suspicion is
loose mounting bolts. Will have to crank it over soon and take a look.

Thanks for the info.

Dave Head

On Sat, 21 Feb 2004 16:38:40 -0500, Bill J wrote:

I have been looking at my beam also thinking it is moving too much in
the wind. It is a Yaesu rotor and a Moseley 4 element beam. Almost looks
like the 2" mast (about 5 ft.) is flexing, but I am pretty sure that
can't be. It is up 45 feet on a Universal Aluminum unguyed tower very
firmly mounted in concrete.

Dave Head wrote:
Hi,

I have a 4 el., 5 band quad on a Yeasu rotator on a Heights Aluminum tower.
The antenna is swinging, in a fairly stiff breeze today, a total of about 20
degrees of arc. Of course that's not a problem with the width of the beam of a
4 el quad, but the 24 el 2 meter antenna I plan to add might have an issue with
that much swing. I forget which model Yeasu rotator it is, but it is supposed
to be big enough for the 4 el. quad (30 ft boom). G450? I think?

Anyway, is 20 degrees in a stiff wind too much? Can I expect the rotator to
fail soon over this? The tower does not appear to be twisting. The rotor base
plate doesn't seem to be moving. I don't think there's that much play in the
bolts of the masting, and the tower appears tight to the mast. I think the
play is in the rotator.

Is it common for a rotator to have that much play?

Dave Head

Dave:

Some of the huge commercial/government system rotators have built in torsion
relief in the form of some sort of springing, but I don't think the smaller
Yaesu have such. I would really be concerned with that much slack, as the
larger the swing is, the more inertia the assembly builds up to pound the
rotator internals into dust. Plus, if that model rotator has a positive
'brake' like the HAM series, then you are in a heap of trouble, as the brake
has definitely failed. Best get it repaired before the spring winds.

--
Crazy George
Remove N O and S P A M imbedded in return address
"Dave Head" wrote in message
...
Hi,

I have a 4 el., 5 band quad on a Yeasu rotator on a Heights Aluminum
tower.
The antenna is swinging, in a fairly stiff breeze today, a total of about
20
degrees of arc. Of course that's not a problem with the width of the beam
of a
4 el quad, but the 24 el 2 meter antenna I plan to add might have an issue
with
that much swing. I forget which model Yeasu rotator it is, but it is
supposed
to be big enough for the 4 el. quad (30 ft boom). G450? I think?

Anyway, is 20 degrees in a stiff wind too much? Can I expect the rotator
to
fail soon over this? The tower does not appear to be twisting. The rotor
base
plate doesn't seem to be moving. I don't think there's that much play in
the
bolts of the masting, and the tower appears tight to the mast. I think
the
play is in the rotator.

Is it common for a rotator to have that much play?

Dave Head

On Sat, 21 Feb 2004 16:43:14 -0600, "Crazy George"
wrote:

Dave:

Some of the huge commercial/government system rotators have built in torsion
relief in the form of some sort of springing, but I don't think the smaller
Yaesu have such. I would really be concerned with that much slack, as the
larger the swing is, the more inertia the assembly builds up to pound the
rotator internals into dust. Plus, if that model rotator has a positive
'brake' like the HAM series, then you are in a heap of trouble, as the brake
has definitely failed. Best get it repaired before the spring winds.

I think its supposed to have a brake. It is a Yeasu 800 DXA. Suspect loose
mounting bolts - it hasn't been up so long for the rotator to simply fail, I
think. The antenna is a Cubex 4 el, 5 band quad that is 7 sq ft and has a 30
ft boom. I think that rotator ought to handle it, as did the guy at Ham Radio
Outlet. He actually talked me up to this one, when I was going to get a 450,
but he pointed out the "K" factor, and how I needed the heavier rotator for
that long boom. Something still isn't right, tho, I think.

It could be the masting, tho. I have a 3: diameter piece that goes into the
rotator and is "pinned" there by a bolt, as well as clamped, then it goes to a
"jackshaft" that is a smaller, about 4' length of 1 3/4" stainless steel with 1
or 2 1/4" bolts thru it. That goes thru the 1 3/4" top section collar, then a
3" heavy aluminum mast slips over the stainless jackshaft and is secured with 2
quarter-inch bolts. There's probably some play in the bolts, but I don't think
there's that much. Mounting bolts on the bottom of the rotator - I think those
may be loose.

Thanks for the info.

Dave Head

Dave

Dave:

From that description, I suspect you are going to find all the bolt holes in
the tubing elongated from torque. We usually drill slightly oversize holes
for our fasteners, but in this high stress application, the holes should
start undersize so the fasteners have to be driven in and are tight from the
get-go. Also, it is necessary to select fasteners which do not have threads
where they pass through the walls of the tubes. This is often the most
difficult challenge.

--
Crazy George
Remove N O and S P A M imbedded in return address
"Dave Head" wrote in message
...

snip
It could be the masting, tho. I have a 3: diameter piece that goes into
the
rotator and is "pinned" there by a bolt, as well as clamped, then it goes
to a
"jackshaft" that is a smaller, about 4' length of 1 3/4" stainless steel
with 1
or 2 1/4" bolts thru it. That goes thru the 1 3/4" top section collar,
then a
3" heavy aluminum mast slips over the stainless jackshaft and is secured
with 2
quarter-inch bolts. There's probably some play in the bolts, but I don't
think
there's that much. Mounting bolts on the bottom of the rotator - I think
those
may be loose.

Thanks for the info.

Dave Head

Dave

On Sun, 22 Feb 2004 14:46:54 -0600, "Crazy George"
wrote:

Dave:

From that description, I suspect you are going to find all the bolt holes in
the tubing elongated from torque. We usually drill slightly oversize holes
for our fasteners, but in this high stress application, the holes should
start undersize so the fasteners have to be driven in and are tight from the
get-go. Also, it is necessary to select fasteners which do not have threads
where they pass through the walls of the tubes. This is often the most
difficult challenge.

That is certainly worth a suspicion or two. I had it tilted over a couple
months ago, after being up for a while, and inspected the bolts and found no
wear. The whole assembly was not "tight" at that time either, and I think it
was the rotor that had the play. But I'll tilt it over again and go through it
all.

Thanks,

Dave Head
K8DH

That was it. There is a 2" aluminum tube over a 1 1/4" stainless steel
"jackshaft". It's held with two 1/4" bolts. Holes thru aluminum tube were
elongated. Drilled to 3/8". Unfortunately, these aren't perfectly round,
either, since I drilled 'em with a hand drill, but I'm hoping the torque I put
on the 3/8" bolts will crush the aluminum tube into clamping on the stainless
steel. We'll see. If not, I can drill more holes thru that assembly and put
more bolts in. It seemed more solid, but next big wind, I'll have a look.

Thanks again for the tip.

Dave Head

On Sun, 22 Feb 2004 14:46:54 -0600, "Crazy George"
wrote:

Dave:

From that description, I suspect you are going to find all the bolt holes in
the tubing elongated from torque. We usually drill slightly oversize holes
for our fasteners, but in this high stress application, the holes should
start undersize so the fasteners have to be driven in and are tight from the
get-go. Also, it is necessary to select fasteners which do not have threads
where they pass through the walls of the tubes. This is often the most
difficult challenge.

Dave:

I've forgotten the exact construction you described, but I suspect you are
going to have to increase the friction between the two tubes by splitting
and clamping the outer. It sounds like the aluminum is simply too thin and
too soft to withstand that kind of torque against a small diameter fastener.

--
Crazy George
Remove N O and S P A M imbedded in return address
"Dave Head" wrote in message
...
That was it. There is a 2" aluminum tube over a 1 1/4" stainless steel
"jackshaft". It's held with two 1/4" bolts. Holes thru aluminum tube were
elongated. Drilled to 3/8". Unfortunately, these aren't perfectly round,
either, since I drilled 'em with a hand drill, but I'm hoping the torque I
put
on the 3/8" bolts will crush the aluminum tube into clamping on the
stainless
steel. We'll see. If not, I can drill more holes thru that assembly
and put
more bolts in. It seemed more solid, but next big wind, I'll have a look.

Thanks again for the tip.

Dave Head

On Sun, 22 Feb 2004 14:46:54 -0600, "Crazy George"

wrote:

Dave:

From that description, I suspect you are going to find all the bolt holes
in
the tubing elongated from torque. We usually drill slightly oversize
holes
for our fasteners, but in this high stress application, the holes should
start undersize so the fasteners have to be driven in and are tight from
the
get-go. Also, it is necessary to select fasteners which do not have
threads
where they pass through the walls of the tubes. This is often the most
difficult challenge.

That is almost as much play as I had in my system, with a 2 el 40 m beam and a
tribander, but I had a 40 ft torque tube down the tower to absorb the forces.

73s,

Evan