In my not certified mechanical engineer opinion, I wouldn't trust a rohn
pointy top as a tapered base. The top tube is relatively thin walled and if
I remember there is only some thing metal wrapped around the bent legs and
welded to the sides of it. to me it looks more like its designed only for
side force of a mast going through it, NOT to support the weight of
anything. I would have it professionally evaluated before trying anything
like that... also of course it would make the swaging upside down.
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
> -----Original Message-----
> From: Donald Hofmann [mailto:electroubleshooter@hotmail.com]
> Sent: Saturday, December 13, 2008 21:35
> To: w9rma@charter.net
> Subject: Re: [TowerTalk] sorry for multiple mails, but had another idea
>
>
> Thanks for the response.
>
> I live in north Texas about 70 miles north of Dallas. There is a strip of
> land from here to south of Dallas that is very unstable. We have clay and
> black gumbo that goes down as deep as 20'. In the hot Texas summers it
> drys and shrinks. Then when it rains, it swells and moves again. The
> foundation leveling companies love this area.
> I could use an inverted top section of tower as you suggested and weld a 2
> 5"16" trailer hitch ball onto it. I would then have to come up with some
> type of socket to bury in the concrete. Also welding would burn the
> galvanized finish off causing me to have to paint it every few years.
>
> I also looked at just using Rohn's single pier pin but I think that if the
> concrete foundation shifts too much it will start causing the tower to
> move out of plumb ( because the steel base plate that the tower is mounted
> on will start to contact the concrete base on the high side). Hope that
> that makes sense! In other words the guys will be holding the tower plumb
> but the concrete will move and contact the bottom of the steel plate. This
> defeats the purpose of a floating pier pin.
> (BTW my current tower installed in 1992 is out of plumb by an entire
> bubble on my torpedo level and this is at GROUND level. At the top it
> might be off 10 or more degrees.)
>
> Also I don't much like the idea of just depending on guys to hold the
> tower up. If they fail the tower comes down. If I mount the steel base
> plate on three bolts at least it won't come down.
>
> I plan on mounting the steel base a inch or more above the concrete so
> that I have plenty of room for adjustment. If need be I can "over
> engineer" it and use 3/4" bolts.
>
> You are right, Rohn sticks it too you. They are reasonable on the straight
> tower sections and give you the shaft on everything else.
>
> 73
>
> Donald W5DWH
>
>
>
> From: w9rma@charter.netTo: electroubleshooter@hotmail.comSubject: RE:
> [TowerTalk] sorry for multiple mails, but had another ideaDate: Sat, 13
> Dec 2008 15:13:03 -0600
>
>
>
>
>
>
>
> Check out some used towers and see if you can get a tower with a ball
> mount on the bottom. If you look at commercial
> Towers many are mounted this way. You might check with someone who who
> mounts towers commercially and see if they
> Make such a unit. You might call Rohn Tower and check with them. Be
> careful about ordering from Rohn they are
> Very expensive as a friend found out. (12 bolts 46",$595.00) A thought
> went through my mind. I am wondering if one
> Could weld a support collar on a over turned 25G top section and mount it
> on a ball mount..hmmmm have to think on
> That one for a while.
>
> Your idea about the plates would also work. I like that idea. I have a
> 100 ft. self supported tower in the yard behind the
> House and it sits on 12 bolts and can be adjusted if the earth ever moved.
> What part of the world do you live that the
> Earth moves? Another way to keep the tower from tilting is to have a
> broad base 4 x4x4 or is it the soil in your area?
> There you would have to ask a engineer about that for the weight of the
> tower plus concrete, cables etc.
> Ron W9RMA
>
>
>
>
>
>
> From: Donald Hofmann [mailto:electroubleshooter@hotmail.com] Sent:
> Saturday, December 13, 2008 14:16To: w9rma@charter.netCc:
> towertalk@contesting.comSubject: RE: [TowerTalk] sorry for multiple mails,
> but had another idea
>
> Thanks for the response. Referring to my current leaning tower I have
> decided that I am better off starting from scratch v.s. trying to level
> the old one for several reasons. One, if I move it I can guy it at the
> correct distance from the tower and two, I can fix the out of plumb tower.
> So my next questions: If I put in a new tower I want the base to be
> adjustable for out of plumb problems.Any thoughts on how to do this?I am
> considering the 25GSSB self supporting base plate. I propose to sink three
> 5/8" galvanized bolts into a concrete foundation. I would then put a nut
> on each bolt then the base plate and then double nuts. The idea being that
> if the ground shifts, I could loosen the guys a little, then adjust the
> nuts until plumb and then retighten the nuts. Any comments or better
> ideas?Also what size concrete base for this installation? I can't find out
> what Rohn recommends for this base plate. Thanks> From: w9rma@charter.net>
> To: electroubleshooter@hotmail.com> Subject: RE: [TowerTalk] sorry for
> multiple mails, but had another idea> Date: Sat, 13 Dec 2008 11:43:57 -
> 0600> > Don:> First of all if you have a fifty foot tower you only have to
> be 80% for your> guy points that is if they go to the ground. If you move
> the guy points up> 4' that means can can come closer to the tower by a few
> points. Second I> used commercial garage coil spring rollers that had been
> taken out of> service and get thrown away.> I put them 4' in the ground
> cemented in with about a yard of concrete and> also fill the tube with
> cement. I well on tabs for the turnbuckles to> attach too.> > The towers
> which some are over 75' ft. have gone through tornados with winds> from>
> 90 - 110 mph and only the mast has bent. Poor choice of mast (water pipe)>
> Use a good mast such as moleychromium. Expensive but worth it in the long>
> run.> Ron W9RMA> > -----Original Message-----> From: towertalk-
> bounces@contesting.com> [mailto:towertalk-bounces@contesting.com] On
> Behalf Of Donald Hofmann> Sent: Friday, December 12, 2008 18:40> To: 'jim
> Jarvis'> Cc: towertalk@contesting.com> Subject: Re: [TowerTalk] sorry for
> multiple mails, but had another idea> > I was thinking that the top plate
> would act as a stabilizer to keep the> tower from twisting, similar to a
> "star" assembly.> > > -----Original Message-----> From: jim Jarvis
> [mailto:jimjarvis@optonline.net] > Sent: Friday, December 12, 2008 6:13
> PM> To: Donald Hofmann> Subject: sorry for multiple mails, but had another
> idea> > > You know, for guy attachment, you can just form a loop and drop
> it over> a > tower leg, as you erect things? You may WANT the flat top, as
> a place> to> stand--but you don't need it for guy attachment.> > sorry for
> the fragmented responses, but I've been juggling waaaay too> many> balls
> here, this week. > > n2ea> > > Jim Jarvis, MBA> President - Executive
> Coach> The Morse Group, LLC> 732 548 5573 office 908 410 9130 cell>
> www.themorsegroup.net> > People-Process-Strategy: Achieving Results in a
> Changing World> > > No virus found in this incoming message.> Checked by
> AVG - http://www.avg.com > Version: 8.0.176 / Virus Database:
> 270.9.16/1843 - Release Date: 12/12/2008> 9:02 AM> >
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