[TowerTalk] newbie, Installing a 80' crank up .
GALE STEWARD
k3nd@yahoo.com
Sat, 9 Oct 1999 11:26:46 -0700 (PDT)
I agree, but it might make a dandy 80/160 shunt fed
vertical!
73, Stew K3ND
--- Tom Wagner <tomwagner@mindspring.com> wrote:
>
> Dave --
>
> You own a dangerous tower.
>
> Sorry to point this out, Dave, but your tower is not
> very strong.
> Go to http://www.ustower.com/selfsupport.html
> and look at the weights and section sizes for a US
> Tower.
> The weight of a 72' light-duty tower is 1040 lbs.
> The base
> face width is 21 5/8" . Tower strength increases
> greatly with
> face width (probably cube or 4th power - a PE would
> know).
>
> Note that the US Tower ratings are for 50 mph. The
> minimum you should design for is 70 mph. Higher
> wind
> speeds are mandated in some counties.
>
> Regarding guying a crank-up tower, it is not usually
> a good
> idea. Guys create very large downward forces. If
> you were to
> add 4 sets of guys to that tower, you would be
> expecting the
> crank-up cable to counteract the downward force of
> 12 guys --
> you better have a big cable! Note: the closer guys
> are to the
> tower, the greater the downward force for a given
> horizontal
> force.
>
> This is very blunt, Dave, but I would not erect an
> 80' crank up tower
> that was light enough for two guys to lift --
> particularly
> if the face width was only 14". This is a serious
> safety matter.
> The tower is dangerous. There are many other
> problems with
> your analysis of this project. You are not nearly
> ready to do this.
> Keep reading this reflector until you are. Towers
> can kill.
>
> Please understand that it would have been much
> easier for me
> to ignore your post, than to respond. If you do not
> believe me,
> please ask a PE. It is not my safety at risk - it's
> yours.
>
> Tom Wagner - N1MM
>
> ----- Original Message -----
> From: Dave H. <wiseguy@attitude.com>
> To: <towertalk@contesting.com>
> Sent: Friday, October 08, 1999 2:46 PM
> Subject: [TowerTalk] newbie, Installing a 80' crank
> up .
>
>
> >
> >Hi to All,
> >
> >
> >I am a new member to this fine forum of information
> "Tower Talk".
> >
> >I have just purchased a 80' crank up Tower . Dont
> know the manufacture .
> >This tower is extremely heavy (two guys can barely
> lift it off the ground)
> >it's galvanized and is in 20' telescopic lengths.it
> is made of 1" tubing,
> >the largest section is 14" x 14" x 14" (a
> triangular design) (inside ones
> >are smaller than the next 4 total= 80') The tower
> has "ears" at the top of
> >each section or tabs to connect guy wires to them.
> The tower is a ladder
> >design and cross bars are horizontal (ladder type)
> not Chris-cross . A bar
> >design,(as opposed to a (X) design.) I hear this is
> not strong like the X
> >design.
> > It can be laid over on two bolts/pins, tilt up
> into place and then one
> >would add the third pin to the base plate.
> >these bolts don't seem strong enough to do much of
> anything other than to
> >keep it into place on the 3/4' steel base plate
> which has 4 large holes at
> >the corners for the base bolts (1" I think) the use
> of 2' long "J" bolts
> >might work well here.
> >I was thinking of a 3x3x3 base pour 4" above grade,
> since the tower is not
> >of the "free standing" variety.
> >But, I live where the soil is considerably
> heavy,(California Desert) when
> >the soil is saturated it becomes terrible, and in
> the summer months it is
> so
> >hard I have to drive a spike with a large hammer in
> the ground just to put
> a
> >sprinkler in place (the type with a 7' spike on
> 'em)
> >
> >As far as placement on the property goes, I have
> enough property to locate
> >it anywhere. So, the $64K question is...do you
> guys think it should be
> AWAY
> >from the house? or, NEXT to the house? if we go
> next to the house, one set
> >of the the guys will be in the front yard. Since I
> have more than ample
> room
> >on this property for the tower and guying. If I set
> the tower away from the
> >house how far should this be? and do I run the
> cables down a nearby guy
> wire
> >or underground from base.?
> >
> >I am guying it 3 ways (120 degrees apart).
> >One of my main concerns is the degree of guying the
> antenna down. I want to
> >get away with going with 30 degrees. Should it be
> guyed at each 20' section
> >or one near the top and one set at the second
> section? which is @ 40'. I
> am
> >going to be running 10 meters, I have a 8 element
> beam by Avanti (AV-140)
> >some know it as a "Moonraker IV". (dimensions are
> 19' boom, from top to
> >bottom each element is 20' has horiz. and vert.
> elements) this antenna has
> a
> >wind load of only 5 sq.. ft. and weighs 24 pounds
> so with this factor, I
> >want this thing to last through "super cell
> storms" with no problem.
> >eventhough I live in a mild climate.
> >I would like to guy with "poles" so one can walk
> around the pole rather
> than
> >trip over ground level turnbuckles. Any comments?
> >The prevailing winds are from the NW and there can
> be gusts of what I've
> >seen in the past 11 years here of about 40 mph. So,
> would pointing or
> guying
> >a tower directly into the prevailing winds benefit
> the load better or
> should
> >I consider the placement of the guy wires first and
> formost in the
> >landscape? what about running two guys off same
> eyelet at 60 degrees into
> >the prevailing wind? or does this matter at all.?
> >Also the issue of running a solid run of guy wires,
> is it truly necessary
> to
> >break these up with insulators? I heard 22' to be
> the rule. I would think
> >just run the guys solid all the way to the tower.
> > I think the solid run of a guy is important and
> that I shouldn't worry
> >about breaking them up for ''coupling or resonance"
> issues. I just was
> >worried about the vertical elements getting too
> close to the top guys and
> >that they are metal because, The worst part is at
> the top. this antenna has
> >9' vertical elements from the boom. if I guy at the
> top eyelet, the tower
> >won't rotate. Is this solved by guying at 10' lower
> point on tower, or
> using
> >a 10' section of mast putting antenna well above
> top plate? or how is it
> >going to turn a vertical beam?
> >
> >I'll need to look into the anchors as well. What do
> you think about having
> >them at ground level with big turnbuckles on them.
> OR getting a large
> >diameter. pole as to be able to walk around the
> guys since they terminate
> >5-6' on to of the pole?Whatever type I decide on
> they will be cemented in.
> >so I need to know what dimensions of a base pour
> these "anchors" should be.
>
=== message truncated ===
=====
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